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SynC · Editorial revision

Medium-Voltage Variable Frequency Drives

Revision1
EditedOct 17, 2026
StatusCurrent
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Current revision. This is editorial revision 1, the current text of this standard. Read it on the standard's page.

SynC Standards Team — Specifier (Platform Standards) ✓ OfficialDiscloses employment SynC (SynC Platform Team)
Initial publication

1 Scope

NOTE This standard governs variable frequency drives procured as separate lineups and field-connected to three-phase motors rated above 600 V, at motor voltages from 2.3 kV through 13.8 kV, on the pumps, blowers, compressors, fans, and conveyors of water, wastewater, industrial, and power facilities. (1.1)
NOTE A medium-voltage drive is a lineup rather than a box: an input section with its isolation and fusing, an input transformer that is most often part of the lineup, a power conversion section whose topology decides the harmonic performance, the output waveform, and the footprint, a cooling system, a control section, and, where selected, a bypass that is itself a medium-voltage motor controller. This standard decides each of those as its own field, because they are bought together but chosen separately. (1.2)
NOTE The following are governed elsewhere and are outside this standard: (1.3)
  • drives rated 600 V and below, under Low Voltage Variable Frequency DrivesLow-Voltage Variable Frequency DrivesResolves to the current adopted revision.sync/low-voltage-variable-frequency-drives for process and industrial service and HVAC Variable Frequency DrivesHVAC Variable Frequency DrivesResolves to the current adopted revision.sync/hvac-variable-frequency-drives for building air and hydronic equipment
  • drives furnished integral to packaged equipment, whose drive requirements belong to the standard governing that equipment
  • the motor rated above 600 V, which is not yet owned by a SynC standard; this standard states what the drive imposes on the motor and the motor standard, when written, states what the motor withstands
  • the stand-alone medium-voltage motor controller or starter that is not part of a drive lineup, which is not yet owned by a SynC standard; the controller and the reduced-voltage starter furnished in the drive lineup as its input isolation or its bypass are this standard's
  • the shielded medium-voltage cable between the drive and the motor and its terminations, under Medium Voltage CablesMedium-Voltage CablesResolves to the current adopted revision.sync/medium-voltage-cables; this standard states the output-side conditions that cable has to meet
  • the switchgear that feeds the drive and the feeder breaker in it, under Medium Voltage SwitchgearMedium Voltage SwitchgearResolves to the current adopted revision.sync/medium-voltage-switchgear
  • a conventional step-down transformer ahead of the drive that is not a multi-winding rectifier transformer of the drive system, under Medium Voltage TransformersMedium-Voltage Distribution TransformersResolves to the current adopted revision.sync/medium-voltage-transformers
  • power-factor correction capacitors, under Power System CapacitorsPower-Factor Correction CapacitorsResolves to the current adopted revision.sync/power-system-capacitors
  • the programmable controller that commands the drive and the network that carries the command, under Programmable Logic ControllersProgrammable Logic ControllersResolves to the current adopted revision.sync/programmable-logic-controllers and Process Control NetworksProcess Control NetworksResolves to the current adopted revision.sync/process-control-networks
  • the short-circuit, coordination, and arc-flash studies, under Short Circuit StudyShort-Circuit StudyResolves to the current adopted revision.sync/short-circuit-study, Protective Coordination StudyProtective Device Coordination StudyResolves to the current adopted revision.sync/protective-coordination-study, and Arc Flash StudyArc-Flash Hazard AnalysisResolves to the current adopted revision.sync/arc-flash-study
  • the harmonic and power-quality study of the facility, which is not yet owned by a SynC standard; this standard states the limits and requires the manufacturer's harmonic analysis of the drives it furnishes
  • the room that houses the lineup, under Electrical RoomsElectrical RoomsResolves to the current adopted revision.sync/electrical-rooms, and the concrete pad as a structure, under Concrete PadsConcrete Equipment PadsResolves to the current adopted revision.sync/concrete-pads
1.4 The horsepower, rated speed, full-load current, and voltage of each driven motor, and the number of drives, shall be as indicated on the motor and drive schedule.
1.5 The drive location, the orientation of the lineup, and the position of a separately mounted input transformer shall be as indicated on the electrical room layout or the site electrical plan.
1.6 The Contractor shall coordinate the supply cable, the motor cable, the upstream feeder breaker, the room, the pad, and the grounding of the lineup with the standards named in this section before the drive is released for manufacture.

2 Referenced Standards

2.1 Equipment, materials, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
2.2 Where the contract documents, the serving utility's requirements, the Authority Having Jurisdiction, or two referenced standards impose conflicting requirements, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
Standard Title
UL 347A Medium Voltage Power Conversion Equipment
UL 347 Medium-Voltage AC Contactors, Controllers, and Control Centers
IEEE 519 Standard for Harmonic Control in Electric Power Systems
IEEE 1566 Standard for Performance of Adjustable-Speed AC Drives Rated 375 kW and Larger
IEEE C57.18.10 Standard Practices and Requirements for Semiconductor Power Rectifier Transformers
IEEE C57.12.01 General Requirements for Dry-Type Distribution and Power Transformers
IEEE C57.12.00 General Requirements for Liquid-Immersed Distribution, Power, and Regulating Transformers
IEEE C37.20.7 Guide for Testing Switchgear Rated Up to 52 kV for Internal Arcing Faults
IEEE C62.22 Guide for the Application of Metal-Oxide Surge Arresters for Alternating-Current Systems
IEC 61800-4 Adjustable Speed Electrical Power Drive Systems, Part 4: General Requirements, Rating Specifications for AC Power Drive Systems Above 1000 V AC
NEMA MG 1 Motors and Generators (Part 31, Definite-Purpose Inverter-Fed Polyphase Motors)
NEMA 250 Enclosures for Electrical Equipment (1000 Volts Maximum)
NFPA 70 National Electrical Code (Article 110 Part III, Article 430 Part XI, and Article 495, numbered Article 490 in editions before 2023)
NFPA 70E Standard for Electrical Safety in the Workplace
ANSI/NETA ATS Standard for Acceptance Testing Specifications for Electrical Power Equipment and Systems
ASCE 7 Minimum Design Loads and Associated Criteria for Buildings and Other Structures (Chapter 13)
ICC-ES AC156 Acceptance Criteria for Seismic Certification by Shake-Table Testing of Nonstructural Components

3 Submittals

3.1 Action Submittals

3.1.1 The Contractor shall submit the following for review before any drive is released for manufacture:
  • a lineup outline drawing showing every section in plan and elevation, the shipping splits, the weight and center of gravity of each shipping section, the lifting provisions, the anchor pattern, the cable entry areas, the cooling air intake and discharge or the coolant connections, and the clearances the manufacturer requires around the lineup
  • a one-line diagram of the lineup showing the input isolation and fusing, the input transformer with its winding arrangement, the rectifier, the inverter, the output filter, the bypass, every contactor, and every instrument transformer, with the rating of each
  • a ratings sheet stating the supply voltage, the motor voltage, the continuous output current, the overload capability, the short-circuit current rating of the lineup, the BIL of the input section, the efficiency at rated load, the heat rejected to the room at rated load, and the sound pressure level
  • the input transformer data: rated kVA, winding arrangement and phase shift, impedance, insulation system and temperature rise, losses, and the harmonic current loading it is designed for
  • the harmonic analysis required under Harmonic Performance
  • the output-side analysis required under Output Side and Motor Compatibility, stating the peak voltage, the rate of voltage rise, and the common-mode voltage at the motor terminals for the installed cable length, and the motor cable length the drive accepts without an output filter
  • the bypass scheme schematic, the sequence of operation, and the interlock diagram, where a bypass is selected
  • the motor protection scheme, the protective functions provided, and the proposed settings
  • control and communication wiring diagrams showing every hardwired input and output, the network interface, and the control power source
  • the derating calculation for ambient temperature and altitude where either exceeds the drive's standard rating basis
  • the seismic qualification certificate for the lineup as configured, where seismic qualification is required
  • the nameplate schedule listing the text to appear on the lineup and section nameplates
Action Submittal Packagecheckbox
☑ Lineup outline drawing
☑ Lineup one-line diagram
☑ Ratings sheet
☑ Input transformer data
☑ Harmonic analysis
☑ Output-side analysis and cable length limit
☐ Bypass scheme schematic and sequence of operation
☑ Motor protection scheme and proposed settings
☑ Control and communication wiring diagrams
☐ Ambient and altitude derating calculation
☐ Seismic qualification certificate
☑ Nameplate schedule
3.1.2 A drive shall not be released for manufacture until the action submittals covering it have been reviewed and returned.

3.2 Informational Submittals

3.2.1 The Contractor shall submit the following with or before the action submittals:
  • the manufacturer's qualification statement required under Quality Assurance
  • the listing or certification evidence required under Quality Assurance
  • the factory test procedure, where a witnessed factory test is selected in the datasheet
  • the field testing firm's qualification statement and the proposed field test procedure for the lineup
  • the motor manufacturer's written acceptance of the drive output conditions stated in the output-side analysis
  • the manufacturer's written statement of the discharge time of the stored energy in the power cells or the DC link after the input is opened
Informational Submittal Packagecheckbox
☑ Manufacturer qualification statement
☑ Listing or certification evidence
☐ Factory test procedure
☑ Field testing firm qualification and test procedure
☑ Motor manufacturer's acceptance of the drive output conditions
☑ Stored-energy discharge time statement

3.3 Closeout Submittals

3.3.1 The Contractor shall submit the following before the drive is accepted:
  • the certified factory test report for the lineup and for the input transformer, identified by serial number
  • the field acceptance test report for the lineup, giving every measured value, the acceptance criterion applied, and the tester's determination
  • the startup report recording the measured supply voltage, the measured harmonic current and voltage distortion at the compliance point, the motor current and speed at each test point, and every vibration-related skip band programmed
  • the final programmed parameter settings for each drive, printed and as the manufacturer's electronic configuration file
  • the as-left settings of every protective function and of the separate motor protection relay where one is furnished
  • record drawings reflecting every field change to the arrangement, the wiring, and the settings
  • the arc-flash incident energy labels installed, with the study revision they were taken from
  • operation and maintenance data covering the lineup, the input transformer, the cooling system, and every protective device, with the parameter reference and the fault code reference
  • the training record listing the sessions held, the attendees, and the material covered
  • the warranty certificate identifying the lineup serial numbers and the warranty commencement date
  • a signed receipt from the Owner for the spare parts delivered
Closeout Submittal Packagecheckbox
☑ Factory test reports
☑ Field acceptance test report
☑ Startup report with harmonic measurements and skip bands
☑ Final parameter settings, printed and as an electronic configuration file
☑ As-left protective settings
☑ Record drawings
☐ Arc-flash label record
☑ Operation and maintenance data
☑ Training record
☑ Warranty certificate
☑ Spare parts receipt

4 Quality Assurance

4.1 Manufacturer Qualifications

4.1.1 The drive shall be produced by a manufacturer that has furnished medium-voltage drives of the topology and voltage class selected for not less than the period indicated in the datasheet.
Manufacturer Production Experiencerange
years
351020
Default: Not less than 5 years
4.1.2 The manufacturer shall maintain a factory-trained field service organization able to reach the site, and shall state the location of the nearest such office in the qualification statement.
4.1.3 The manufacturer shall commit in writing to supplying replacement power cells, control boards, and firmware support for the drive platform for not less than ten years from the date of shipment.
NOTE A medium-voltage drive platform outlives the semiconductor generation it was built on, and the Owner who cannot buy a replacement power cell in year eight owns a lineup that is retired by one failed cell. The support commitment is what the Owner holds when that day comes. (4.1.4)

4.2 Listing and Certification

4.2.1 The listing basis of the lineup shall be as indicated in the datasheet.
Lineup Listing Basisradio
● Listed to UL 347A by a Nationally Recognized Testing Laboratory
○ Field evaluation and label by a Nationally Recognized Testing Laboratory
NOTE UL 347A is the safety standard written for medium-voltage power conversion equipment, and a lineup listed to it is accepted by an Authority Having Jurisdiction without further evaluation. A field evaluation is the route for a drive built outside a listed platform, a drive of a topology the manufacturer has not had listed, or a lineup modified for the project beyond its listing, and it is performed on the installed equipment at the site, so a deficiency found there is corrected after delivery. (4.2.2)
4.2.3 The integral medium-voltage contactor, the fused isolating switch where it incorporates a contactor, and the bypass controller shall comply with UL 347.
4.2.4 The drive shall comply with IEEE 1566 for the performance parameters that standard defines, and the manufacturer shall state in the ratings sheet which performance class of IEEE 1566 the drive meets for each parameter.
NOTE IEEE 1566 is the one North American standard that defines how a large drive's performance is stated: its overload, its speed and torque regulation, its ride-through, its efficiency basis, and its tests. Two drives whose catalog claims look alike are compared only when both are stated on that basis. (4.2.5)
4.2.6 The input transformer shall comply with IEEE C57.18.10 for its rating, its harmonic loading, and its tests, and with IEEE C57.12.01 for a dry-type unit or IEEE C57.12.00 for a liquid-immersed unit for everything IEEE C57.18.10 does not address.

4.3 Field Testing Firm

4.3.1 Field acceptance testing of the lineup shall be performed by the firm indicated in the datasheet.
Field Acceptance Testing Firmradio
○ Independent testing firm accredited to ANSI/NETA ATS
○ Manufacturer's field service organization
○ Independent testing firm for the electrical tests and the manufacturer for the functional tests
NOTE An independent firm has no stake in whether the lineup passes and reports against a published acceptance standard; the manufacturer's organization knows the power cells, the control, and the bypass sequence best and is already on site for startup; a split program gives the insulation, connection, transformer, and relay tests to the firm whose instruments and criteria are built for them and gives the drive's functional tests to the party that can reprogram the drive when a test finds something. Which the Owner wants depends on whether a report from the party who built the equipment would satisfy the Owner's insurer and the Authority Having Jurisdiction, and on who is on site when. (4.3.2)
4.3.3 The field testing firm shall be qualified in accordance with Electrical Acceptance TestingElectrical Acceptance TestingResolves to the current adopted revision.sync/electrical-acceptance-testing, and its technicians shall hold a current certification for medium-voltage equipment testing from NETA or from the manufacturer of the equipment tested.

5 Environmental and Service Conditions

5.1 Ambient Temperature

5.1.1 The drive shall deliver its rated continuous output current at the design ambient temperature of the room indicated in the datasheet.
Indoor Design Ambient Temperaturerange
°C
30404550
Default: Not less than 40 °C
NOTE The rating basis of IEC 61800-4 and of IEEE 1566 is a 40 °C maximum ambient, so a 40 °C design ambient is the condition at which the nameplate applies without correction; a higher value buys margin for a room whose ventilation cannot hold that ambient with the drive at rated load, at the cost of a larger drive or a liquid-cooled one for the same nameplate. (5.1.2)
5.1.3 Where the lineup is installed outdoors in its own housing and Site Ambient Temperature MaximumSite Ambient Temperature MaximumParameterEach project supplies its own value.site-ambient-temperature-maximum exceeds 40 °C, the manufacturer shall derate the drive and the input transformer in accordance with its published factors and shall state the derated ratings in the ratings sheet.
5.1.4 Where the lineup is installed outdoors or in an unconditioned space, the enclosure space heaters shall be sized to hold the interior of every section above the dew point at Site Ambient Temperature MinimumSite Ambient Temperature MinimumParameterEach project supplies its own value.site-ambient-temperature-minimum, and shall be supplied from a circuit that stays energized with the drive input open.
NOTE A power cell that cools below the dew point of the air trapped around it condenses water onto a printed circuit board carrying several kilovolts, and the first energization after a cold night is when that is discovered. (5.1.5)

5.2 Altitude

5.2.1 The drive, its input transformer, and its input section shall be derated for AltitudeAltitudeParameterEach project supplies its own value.altitude in accordance with the manufacturer's published correction factors where the altitude exceeds 3,300 ft, for both dielectric clearance and cooling, and the derated ratings shall be stated in the ratings sheet.
5.2.2 Ambient temperature derating and altitude derating shall be applied cumulatively where both conditions apply.
NOTE Air thins with altitude, which reduces both the dielectric strength of the air clearances in a lineup whose bus and power cells stand at several kilovolts and the convective cooling that sets the output current, so a lineup rated at sea level carries less current and less insulation margin at elevation than its nameplate states. (5.2.3)

5.3 Seismic Qualification

5.3.1 The seismic qualification of the lineup shall be as indicated in the datasheet.
Seismic Qualificationselect
Not required
Shake-table qualification per ICC-ES AC156 with component importance factor 1.0
Shake-table qualification per ICC-ES AC156 with component importance factor 1.5
Qualification by analysis per ASCE 7 Chapter 13
Derived — Seismic Design CategorySeismic Design CategoryParameterEach project supplies its own value.seismic-design-category and the component importance factor ASCE 7 Chapter 13 assigns to the lineup (by default)
5.3.2 Where seismic qualification is required, it shall be performed in accordance with the seismic provisions of Adopted Building CodeAdopted Building CodeParameterEach project supplies its own value.adopted-building-code and ASCE 7 Chapter 13, and shall cover the lineup in the configuration shipped, including the input transformer where it is part of the lineup, the heaviest arrangement of power cells, and the cooling equipment.
NOTE Whether the lineup must be qualified follows from the seismic design category, and whether it must remain operable after the design earthquake, rather than merely stay anchored, follows from the component importance factor; neither is decided within this standard. (5.3.3)

6 Drive Ratings

6.1 Supply Voltage and Frequency

6.1.1 The nominal supply voltage at the drive input terminals shall be as indicated in the datasheet.
Supply Voltage at the Drive Inputrange
kV
2.44.164.86.97.2111212.4713.213.8
Per drawings — the one-line diagram (deferred by default)
NOTE The supply voltage and the motor voltage are two decisions: a drive with an integral input transformer accepts a supply at one voltage class and delivers an output at another, so a 13.8 kV distribution system drives a 4.16 kV motor through the drive's own transformer with no separate step-down. Where the supply is above 13.8 kV, the step-down to the drive input is a transformer under Medium Voltage TransformersMedium-Voltage Distribution TransformersResolves to the current adopted revision.sync/medium-voltage-transformers. (6.1.2)
6.1.3 The supply frequency shall be as indicated in the datasheet.
Supply Frequencyradio
● 60 Hz
○ 50 Hz
6.1.4 The drive shall carry a supply voltage variation of plus or minus 10 percent of nominal and a frequency variation of plus or minus 5 percent without tripping or requiring operator intervention, and the manufacturer shall state in the ratings sheet the output available at the low end of that range.
6.1.5 The Contractor shall confirm the nominal supply voltage, the system grounding, and the available fault current at the drive input with the short-circuit study performed under Short Circuit StudyShort-Circuit StudyResolves to the current adopted revision.sync/short-circuit-study before the drive is released for manufacture, and shall report any difference from the one-line diagram to the Engineer of Record.

6.2 Motor Voltage Class

6.2.1 The rated voltage of the motor the drive delivers to shall be as indicated in the datasheet.
Motor Voltage Classrange
kV
2.32.43.344.164.866.66.9101113.213.8
NOTE The motor voltage is decided with the motor, the cable, and the topology in view rather than against the supply. A 4.16 kV motor is the class the widest range of drive topologies deliver directly and the class most pump and fan motors through a few thousand horsepower are wound for; a 2.3 kV motor is the class of older plants and of some compressors, and the lowest class a medium-voltage drive serves; a 6.6 kV or 6.9 kV motor halves the current of a 4.16 kV motor of the same rating and is the class large blowers and compressors are wound for where the cable run is long; a 13.8 kV motor is wound for the very largest machines and is delivered directly only by a cascaded multilevel drive with enough cells in series, or through an output transformer from a lower-voltage inverter. Each class is built, and which one a project wants follows from the motor it is buying, so this field carries no default. (6.2.2)
6.2.3 A drive that delivers a motor voltage above its inverter's native voltage through an output transformer shall be furnished with that transformer as part of the lineup, rated for the drive's output waveform at every speed in the operating range.

6.3 Output Current and Overload Duty

6.3.1 The continuous output current of the drive at the selected duty, after any ambient temperature and altitude derating, shall be not less than the nameplate full-load current of the connected motor.
6.3.2 The overload duty of the drive shall be as indicated in the datasheet.
Overload Dutyradio
● Variable torque, 110 percent of rated current for 60 seconds
○ Constant torque, 150 percent of rated current for 60 seconds
NOTE Centrifugal pumps, blowers, fans, and compressors load their shaft along the cube of speed and present no starting torque demand, so the variable torque overload covers their acceleration and their transients, and they are the loads nearly every medium-voltage drive in a water, wastewater, or power plant serves. A conveyor, a reciprocating compressor, a positive displacement blower, an extruder, or a mill loads the shaft at every speed and draws on the constant torque rating, which is bought with a larger inverter for the same motor. (6.3.3)
6.3.4 The drive shall deliver the motor's rated torque continuously from the lowest operating speed to the rated speed without a separate blower on the motor, unless the motor manufacturer's acceptance submitted under Informational Submittals states a minimum continuous speed and the drive is programmed to that minimum.
6.3.5 Regeneration capability shall be as indicated in the datasheet.
Regeneration Capabilityradio
● Not required, motoring only
○ Four-quadrant regenerative, returning braking energy to the supply
NOTE A pump or a fan stops by coasting, and a drive that only motors lets it; a conveyor on a decline, a downhill belt, a large fan that must stop within a set time, or a machine that reverses under load has energy to put somewhere, and a regenerative drive returns it to the supply instead of into a resistor. Regeneration follows from the topology selected under Power Conversion Topology: a current-source drive and an active front end regenerate as built, and a diode-fed voltage-source drive does not. (6.3.6)

6.4 Short-Circuit Current Rating

6.4.1 The short-circuit current rating of the lineup, including the input section, the input transformer where it is part of the lineup, and the bypass, shall be as indicated in the datasheet.
Lineup Short-Circuit Current Ratingrange
kA
12.516202531.5405063
Derived — the available symmetrical fault current at the drive input terminals established by the short-circuit study, with the momentary, fault-closing, and interrupting ratings of the input section each not less than the corresponding duty (by default)
NOTE The study establishes the duty and the lineup is rated to it, so the field records a consequence of the one-line diagram rather than a preference; a fused input section carries a momentary and a fault-closing rating with the fuses interrupting the fault, and a contactor input section carries the same with the fuses coordinated to protect the contactor. (6.4.2)
6.4.3 The short-circuit current rating shall be established for the lineup as tested under its listing or certification, and shall not be established by combining the ratings of its components on paper.

6.5 Input Insulation Level

6.5.1 The basic impulse insulation level of the input section shall be as indicated in the datasheet.
Input Section BILrange
kV
607595110
Derived — the supply voltage at the drive input and AltitudeAltitudeParameterEach project supplies its own value.altitude, per the voltage classes of UL 347 for the input section (by default)
6.5.2 The input section shall be furnished with metal-oxide surge arresters at the incoming terminals, applied in accordance with IEEE C62.22 to protect the input transformer winding and the rectifier, where the datasheet selects them under Input Section Provisions.

6.6 Efficiency at Rated Load

6.6.1 The efficiency of the lineup at rated load and rated speed, measured from the supply terminals to the motor terminals and including the input transformer, the output filter, and the cooling system auxiliaries, shall be not less than the value indicated in the datasheet.
Lineup Efficiency at Rated Loadrange
%
94959696.59797.59898.599
NOTE The efficiency figure that matters is the one that includes the transformer, because a manufacturer that states the inverter alone states a number two points higher than the lineup delivers. A cascaded multilevel drive with its integral transformer lands near 96 percent at rated load, a voltage-source drive with a separate transformer near 96 to 97 percent for the pair, and a current-source drive with its reactor and transformer in a comparable range; the difference across topologies at rated load is a point or so, and the difference between a stated and an unstated transformer is larger than that. The value a project wants follows from the energy price and the hours the drive runs near rated load, so this field carries no default. (6.6.2)
6.6.3 The manufacturer shall report the lineup efficiency at 100, 75, 50, and 25 percent of rated speed on a variable torque load in the ratings sheet, on the measurement basis IEEE 1566 defines.
6.6.4 The heat rejected to the room at rated load, stated in the ratings sheet, shall be the difference between the input power and the output power at rated load less any heat removed by a liquid cooling loop, and the Contractor shall furnish that figure to the mechanical trade before the room ventilation or cooling design is fixed.

6.7 Sound Pressure Level

6.7.1 The sound pressure level of the lineup at rated load, measured at 1 m from the enclosure surface at the position of highest reading, shall not exceed the value indicated in the datasheet.
Sound Pressure Level at 1 mrange
dBA
657075808590
NOTE An air-cooled lineup's sound is its fans, and a lineup at rated load with its fans at full speed stands near 80 to 85 dBA at 1 m; a liquid-cooled lineup is quieter at the enclosure and moves the fan noise to the heat exchanger. The value a project wants follows from where the lineup stands and who works beside it: an electrical room that is entered to inspect and leave tolerates a level a control room or an occupied plant floor does not. (6.7.2)

7 Power Conversion Topology

7.1 Topology Selection

7.1.1 The power conversion topology shall be as indicated in the datasheet.
Power Conversion Topologyselect
Cascaded H-bridge multilevel voltage-source inverter with integral multi-winding phase-shifting transformer
Neutral-point-clamped multilevel voltage-source inverter
Current-source pulse-width-modulated inverter
Load-commutated inverter for a synchronous motor
NOTE A cascaded H-bridge drive stacks low-voltage power cells in series on each output phase, each cell fed from its own secondary winding of a multi-winding transformer whose phase shifts cancel the input harmonics; it delivers a near-sinusoidal output with a low voltage step and a low common-mode voltage, which is what lets it feed a standard motor over a long cable without an output filter, and it is built directly at every motor voltage class in this standard by adding cells. It is the largest lineup for a given rating because the transformer is inside it, its transformer is its single most expensive component, and a failed cell is bypassed and the drive keeps running at reduced voltage where cell bypass is furnished. (7.1.2)
NOTE A neutral-point-clamped drive synthesizes the output from a small number of high-voltage devices switching between a few levels, so it is the smallest and lightest inverter for its rating and the one most often fed from a separately mounted transformer or, on a 4.16 kV supply, from a 12-pulse or 24-pulse rectifier in the lineup. Its output voltage steps are larger than a cascaded drive's, so it imposes more voltage stress and a higher common-mode voltage on the motor and usually carries an output filter beyond a short cable, and its native output is 2.3 kV through 4.16 kV, with higher motor voltages reached through an output transformer. (7.1.3)
NOTE A load-commutated inverter is a thyristor drive whose inverter is commutated by the back EMF of a synchronous motor, so it is applied only to a synchronous machine and needs that machine's excitation system to run. It is the lowest-cost topology at the very largest ratings, tens of thousands of horsepower, and it draws a 6-pulse or 12-pulse input current with the harmonics that implies, produces torque pulsations at low speed that a large compressor or fan train is checked against, and delivers no torque at standstill without a pulsed starting mode. (7.1.5)
7.1.6 A load-commutated inverter shall be applied only to a synchronous motor, and the drive manufacturer shall coordinate the motor's excitation system, its damper winding, and its torsional response with the motor manufacturer before the drive is released for manufacture.
7.1.7 Where a cascaded H-bridge drive is selected, power cell bypass shall be as indicated in the datasheet.
Power Cell Bypassradio
○ Not furnished
● Automatic bypass of a failed cell with continued operation at reduced output voltage
7.1.8 Where power cell bypass is furnished, the drive shall rebalance the output voltages across the remaining cells, shall alarm the bypassed cell, and shall state in the ratings sheet the output voltage available with one cell bypassed on each phase.
NOTE A bypassed cell shorts itself out of the series string and the drive runs on with the voltage the remaining cells can make, which on a pump or a fan is a few percent less speed until the cell is replaced at a planned stop rather than a trip at an unplanned one. (7.1.9)

7.2 Power Cell Construction and Replacement

7.2.1 Each power cell or power module shall be removable and replaceable from the front of the lineup, with the drive de-energized and the stored energy discharged, by one or two persons without a crane and without disturbing an adjacent cell.
7.2.2 Every power cell or power module of the same rating in the lineup shall be interchangeable, and a replacement cell shall need no factory adjustment to be put into service.
7.2.3 Every semiconductor device in the power conversion section shall be protected against a device failure by a means the manufacturer states in the product data, and the drive shall report which device or cell has failed at the operator interface.

8 Input Transformer

8.1 Transformer Arrangement

8.1.1 The arrangement of the input transformer shall be as indicated in the datasheet.
Input Transformer Arrangementradio
○ Integral to the drive lineup
○ Separately mounted and cable-connected to the drive
NOTE An integral transformer is part of the drive's listing, its throat, its cooling, and its warranty, and it adds the transformer's footprint and heat to the room the drive stands in; a separately mounted transformer stands where the room, the yard, or the vault needs it, is cooled apart from the drive, and lets a liquid-immersed unit carry the drive's rectifier load outdoors, at the cost of a medium-voltage cable or bus between the two and a second party to call when the transformer and the drive disagree. The cascaded multilevel topology is built around its integral transformer and is not furnished without one; the other topologies are furnished either way. (8.1.2)
8.1.3 The construction of the input transformer shall be as indicated in the datasheet.
Input Transformer Constructionradio
○ Dry-type
○ Liquid-immersed
NOTE A dry-type transformer has no liquid to contain or to burn and is the construction every integral transformer and nearly every indoor separately mounted transformer is built with; a liquid-immersed transformer is smaller, lower in loss, and sealed against its environment, and it is the construction a separately mounted transformer standing outdoors or in a vault is built with, bringing the fire-point and spill-containment obligations of its liquid. (8.1.4)
8.1.5 A liquid-immersed input transformer shall be separately mounted, and an integral transformer shall be dry-type.

8.2 Multi-Winding Rectifier Transformer

8.2.1 Where the input transformer is a multi-winding transformer whose secondary windings feed the rectifiers of the drive, whether integral or separately mounted, it shall be furnished by the drive manufacturer as part of the drive system, designed to IEEE C57.18.10 for the rectifier connection, the phase shifts, and the harmonic currents of the drive it feeds.
8.2.2 The multi-winding transformer shall be rated to carry the drive's rated input current with the harmonic spectrum the rectifier draws, continuously at the design ambient temperature, without exceeding the temperature rise of its insulation system, and the manufacturer shall state the harmonic loading basis in the input transformer data.
8.2.3 The transformer shall carry an electrostatic shield between the primary and the secondary windings, grounded to the lineup ground bus.
8.2.4 The multi-winding transformer shall be furnished with winding temperature sensing on each phase, with an alarm and a trip wired to the drive control, and with the taps the manufacturer's standard design provides.
NOTE A multi-winding rectifier transformer is a transformer and something more: its phase shifts are the harmonic cancellation of the drive, its secondaries are rated for the pulsed current of the cells, and its impedance limits the fault current a cell failure draws, so a transformer bought from a general transformer catalog to a kVA and a voltage does not do the job. That is why it is the drive manufacturer's to furnish, and why a conventional step-down transformer ahead of the drive, which is a transformer and nothing more, belongs to Medium Voltage TransformersMedium-Voltage Distribution TransformersResolves to the current adopted revision.sync/medium-voltage-transformers. (8.2.5)
8.2.6 Where the drive is fed through a conventional two-winding transformer that is not a rectifier transformer of the drive system, that transformer shall comply with Medium Voltage TransformersMedium-Voltage Distribution TransformersResolves to the current adopted revision.sync/medium-voltage-transformers, and the drive manufacturer shall state in the input transformer data the K-factor rating or the harmonic derating that transformer needs to carry the drive's input current.

9 Harmonic Performance

9.1 Harmonic Mitigation

9.1.1 The harmonic mitigation of the drive's input shall be as indicated in the datasheet.
Harmonic Mitigationselect
12-pulse multi-winding rectification
18-pulse multi-winding rectification
24-pulse multi-winding rectification
30-pulse or higher multi-winding rectification
Active front end
NOTE Multi-pulse rectification cancels input harmonic orders by feeding parallel rectifier bridges from transformer secondaries shifted in phase: 12-pulse leaves the 11th and 13th orders and the orders above them, 18-pulse leaves the 17th and 19th, 24-pulse the 23rd and 25th, and a cascaded drive with many cells reaches 30-pulse and beyond, at which point the input current distortion is a few percent with no filter at all. The pulse count is a property of the topology and the transformer: a cascaded H-bridge drive's pulse count is set by its cell count per phase, so a 4.16 kV drive with three cells per phase is an 18-pulse drive and a 13.8 kV drive with nine cells per phase is a 54-pulse drive, while a neutral-point-clamped or current-source drive is 12-pulse or 24-pulse by its transformer. An active front end replaces the diode or thyristor bridge with a switched stage that synthesizes near-sinusoidal input current, holds the input power factor near unity, and regenerates, at a higher cost than a multi-pulse rectifier of the same rating and with a line-side switching emission a diode bridge does not have. (9.1.2)
9.1.3 Where the selected harmonic mitigation is a property of the topology selected under Power Conversion Topology, the manufacturer shall state the pulse count of the drive furnished in the ratings sheet, and the two selections shall agree.
9.1.4 Where an active front end is selected, the drive shall regulate the input displacement power factor to not less than 0.98 from 25 percent to 100 percent of rated load.
9.1.5 A multi-pulse drive without an active front end shall draw an input displacement power factor of not less than 0.95 from 25 percent to 100 percent of rated load.

9.2 Compliance Point and Distortion Limits

9.2.1 The point at which harmonic compliance is evaluated shall be as indicated in the datasheet.
Harmonic Compliance Pointradio
○ Point of common coupling with the serving utility
○ Medium-voltage bus serving the drive
○ Drive input terminals
NOTE IEEE 519 sets its limits at the point of common coupling with the utility, where the facility's load as a whole is seen, and compliance there is what the utility's interconnection agreement asks for; a limit applied at the medium-voltage bus serving the drive protects the other loads on that bus, the generators that parallel with it, and the capacitors connected to it, and is the point a plant with its own generation or a sensitive process holds the drive to; a limit applied at the drive input terminals is the strictest, because the drive alone must meet it with no diversity from other loads, and it is the point a drive on a weak or generator-fed source is held to. The choice follows from who the distortion harms, so this field carries no default. (9.2.2)
9.2.3 The current total demand distortion at the compliance point, with the drive at rated load and every other drive furnished under this standard at its rated load, shall not exceed the limit indicated in the datasheet.
Total Demand Distortion Limit at the Compliance Pointrange
%
58121520
Derived — the ratio of available short-circuit current to maximum demand load current at the compliance point, per the current distortion limits of IEEE 519 (by default)
NOTE IEEE 519 sets the current distortion limit as a function of the ratio of the available short-circuit current to the maximum demand load current at the compliance point: a weak point, with that ratio below 20, carries a 5 percent limit, and a stiffer point carries 8, 12, 15, or 20 percent as the ratio rises. The limit is a property of the compliance point rather than of the drive, which is why it is derived from the study's figures rather than chosen, and why a project that wants a tighter limit than the table gives enters it here. (9.2.4)
9.2.5 The voltage total harmonic distortion at the compliance point shall not exceed 5 percent for a compliance point above 1 kV through 69 kV, or 8 percent for a compliance point at 1 kV and below, and no individual harmonic order shall exceed the individual limit IEEE 519 assigns to that voltage.
9.2.6 The Contractor shall confirm the available short-circuit current and the maximum demand load current at the compliance point from the short-circuit study performed under Short Circuit StudyShort-Circuit StudyResolves to the current adopted revision.sync/short-circuit-study and from the facility's load data, and shall furnish both to the drive manufacturer for the harmonic analysis.

9.3 Manufacturer's Harmonic Analysis

9.3.1 The drive manufacturer shall submit a harmonic analysis of every drive furnished under this standard, computed at the compliance point with the available short-circuit current and the maximum demand load current furnished to it, showing the current distortion by order through the 50th, the total demand distortion, and the voltage distortion, with every drive at rated load and at 50 percent speed.
9.3.2 The harmonic analysis shall include the drives furnished under this standard, every other nonlinear load the Contractor identifies to the manufacturer, and the effect of every power-factor correction capacitor and filter connected at or below the compliance point, and an analysis of the drives one at a time shall not be accepted in its place.
9.3.3 Where the harmonic analysis shows that the selected harmonic mitigation does not meet the limits at the compliance point, the Contractor shall report the shortfall to the Engineer of Record before the drive is released for manufacture, and the mitigation shall not be changed without the Engineer of Record's acceptance in writing.
NOTE A harmonic study of the facility as a whole is a power-quality study and not the drive manufacturer's work, and the analysis required here is of the drives the manufacturer furnishes, computed with the facility figures it is given. Where the facility has a harmonic study of its own, the two are reconciled by the Engineer of Record; where it does not, the manufacturer's analysis is the only one there is, which is why it has to include every nonlinear load it is told about. (9.3.4)

10 Output Side and Motor Compatibility

10.1 Output Waveform and the Motor Insulation Basis

10.1.1 The drive manufacturer shall state in the output-side analysis the peak voltage at the motor terminals, the rise time of that voltage, and the common-mode voltage imposed on the motor winding with respect to ground, for the topology furnished, the output filter selected, and the motor cable length as indicated on the conduit and cable schedule.
10.1.2 The peak voltage at the motor terminals shall not exceed 2.04 times the motor's rated line-to-line voltage, and the rise time of that voltage shall be not less than 1 µs, which are the limits NEMA MG 1 Part 31 sets for a definite-purpose inverter-fed motor rated above 600 V, unless the motor manufacturer's acceptance submitted under Informational Submittals accepts a greater stress in writing.
10.1.3 Where the common-mode voltage the drive imposes on the motor winding exceeds the level the motor manufacturer accepts in writing, the drive shall be furnished with a common-mode filter, an output transformer, or another means the manufacturer states, so that the accepted level is not exceeded.
NOTE The motor rated above 600 V is not owned by a SynC standard, and this article states what the drive imposes on it rather than what it withstands: the drive manufacturer states the stress at the terminals, the motor manufacturer states in writing that its insulation system carries that stress, and the Contractor holds both statements before either is released. NEMA MG 1 Part 31 gives the limits a definite-purpose inverter-fed motor above 600 V is built to, and a motor built to Part 31 is the basis against which the drive's output is judged where no other acceptance exists. (10.1.4)
NOTE A voltage-source inverter switches its output between levels in a fraction of a microsecond, and each edge travels down the cable and partially reflects at the motor terminals, where the cable's and the winding's surge impedances differ; a cascaded drive with many small steps and a current-source drive with a capacitor-smoothed output impose a fraction of the stress a three-level inverter does over the same cable. The common-mode voltage, the voltage of the winding neutral with respect to ground, is a separate stress that the phase-to-phase waveform does not show, and on a topology that does not cancel it the winding's ground insulation sees it on every switching cycle. (10.1.5)

10.2 Output Filter

10.2.1 The output filter furnished between the drive and the motor shall be as indicated in the datasheet.
Output Filterselect
None
dv/dt filter
Sine-wave filter
NOTE No filter is the arrangement of a cascaded drive on nearly any cable and of a current-source drive, whose outputs are already within the motor's limits, and of a three-level drive on a cable shorter than the length the manufacturer publishes for the motor's insulation; a dv/dt filter slows the rate of voltage rise and clips the terminal peak so that a three-level drive meets the Part 31 limits over a cable beyond that length, at a few percent of the drive's cost and almost no loss; a sine-wave filter reconstructs a sinusoidal voltage at the motor, which removes the switching stress entirely, lets a motor of unverified insulation or an existing motor run on the drive, and permits the longest cable, at the largest cost, a loss of a percent or so, and a footprint of its own. The filter follows from the topology, the cable length, and the motor's insulation, so this field carries no default. (10.2.2)
10.2.3 The output filter shall be furnished by the drive manufacturer as part of the lineup, listed or certified with it, and rated for the drive's output frequency range and the motor cable length as indicated on the conduit and cable schedule.
10.2.4 Where the installed motor cable length exceeds the length the drive manufacturer states in the output-side analysis as acceptable without a filter, an output filter shall be furnished whether or not the datasheet selects one, and the Contractor shall report the change to the Engineer of Record.

10.3 Output Cable Conditions

10.3.1 The cable between the drive output terminals and the motor shall comply with Medium Voltage CablesMedium-Voltage CablesResolves to the current adopted revision.sync/medium-voltage-cables, and shall in addition be rated by its manufacturer for continuous operation at the peak voltage, the rate of voltage rise, and the common-mode voltage the drive imposes as stated in the output-side analysis.
10.3.2 The output cable shall be shielded, with the shield grounded at the drive output ground bus and at the motor terminal box, and shall be installed as three single-conductor cables in one raceway or as one three-conductor cable so that the three phases share a common magnetic path.
10.3.3 The drive output terminals, the output filter, and the output cable shall be rated for the drive's output frequency range, including the harmonic content of the output waveform at the lowest operating speed.
NOTE Three phase conductors in separate raceways carry an unbalanced high-frequency flux through the steel between them, which heats the raceway and raises the common-mode current, and a shield grounded at one end only leaves the far end at a voltage the switching edge sets; both are output-side conditions the cable standard does not know about, which is why they are stated here for the cable to meet. (10.3.4)

10.4 Motor Bearing and Shaft Currents

10.4.1 The drive manufacturer shall state in the output-side analysis whether the drive's common-mode voltage calls for an insulated bearing, a shaft grounding device, or both on the motor, and the Contractor shall furnish that statement to the motor supplier before the motor is released for manufacture.
NOTE Bearing protection is a motor feature and the motor is not owned by a SynC standard, so this standard requires only that the drive manufacturer state what its output calls for; a cascaded drive's common-mode voltage is low enough that many motors on it carry no shaft protection, and a three-level drive's is high enough that the motor on it usually carries an insulated non-drive-end bearing at least. (10.4.2)

11 Speed Range and Dynamic Performance

11.1 Operating Speed Range

11.1.1 The drive shall operate the motor continuously at any speed from the lowest operating speed to the highest operating speed indicated in the datasheet.
Lowest Operating Speedrange
%
10202530405060
Highest Operating Speedrange
%
100105110115120
NOTE The lowest speed is a property of the driven machine and the system it serves rather than of the drive: a pump on a system whose head is mostly static delivers nothing below the speed at which its shutoff head meets the static head, a fan with a stall region is kept above it, and a self-ventilated motor is kept above the speed at which its own fan no longer cools it at rated torque, which the motor manufacturer's acceptance states. The value follows from those limits, so this field carries no default. (11.1.2)
11.1.3 Where the highest operating speed exceeds 100 percent of the motor's rated speed, the Contractor shall obtain the written confirmation of the motor manufacturer and of the driven equipment manufacturer that the rotor, the bearings, the coupling, and the impeller or rotor of the driven machine are rated for the elevated speed.
11.1.4 The drive shall provide not fewer than three programmable skip bands, each with an adjustable center frequency and bandwidth, and the resonant speeds identified at startup shall be programmed as skip bands before the drive is placed in service.

11.2 Speed and Torque Regulation

11.2.1 The motor control method shall be as indicated in the datasheet.
Motor Control Methodselect
Open-loop volts-per-hertz control
Sensorless vector control
Closed-loop vector control with a shaft encoder
NOTE Volts-per-hertz control sets the output voltage in proportion to frequency and is all a centrifugal pump or fan needs, with no motor model and nothing to tune; sensorless vector control estimates the motor's flux and torque from its currents and holds speed within a fraction of a percent and torque at low speed, which a conveyor, an extruder, or a compressor that must start against load calls for; closed-loop vector control adds an encoder on the motor shaft and holds speed and torque to the tightest regulation, down to standstill, at the cost of an encoder on a medium-voltage motor and the cable and the feedback card that serve it. (11.2.2)
11.2.3 The drive shall hold the motor speed within the regulation band IEEE 1566 assigns to the control method furnished, and the manufacturer shall state the band in the ratings sheet.
11.2.4 The drive shall provide independently adjustable acceleration and deceleration ramp times from 1 second to not less than 600 seconds, with a selectable linear or S-curve profile, and the ramp times shall be set at startup for the installed load.
11.2.5 The drive shall limit output current electronically so that a sudden load increase reduces speed rather than tripping the drive, and shall trip only where the current remains outside its limit after that reduction.

11.3 Power Loss Ride-Through and Restart

11.3.1 On loss of the supply, the drive shall ride through an interruption of not less than the duration indicated in the datasheet without tripping, by sustaining its control from stored energy and, where selected, by regenerating from the load inertia.
Power Loss Ride-Through Durationrange
seconds
0.10.20.5125
NOTE A ride-through measured in a few tenths of a second covers the utility's reclosing and the voltage dips a nearby fault produces, and is what the drive's own stored energy gives; a ride-through measured in seconds is bought by letting the drive's control stay alive while the inverter regenerates from the spinning load, and is what a plant whose process cannot tolerate a restart asks for on a high-inertia fan or blower. The value follows from the process and the supply, so this field carries no default. (11.3.2)
11.3.3 Where the supply returns within the ride-through duration, the drive shall resynchronize to the still-rotating motor and resume at the commanded speed without a stop.
11.3.4 Where the supply is lost for longer than the ride-through duration, the drive shall stop, and the automatic restart behavior shall be as indicated in the datasheet.
Automatic Restart After a Supply Lossradio
○ Enabled with flying restart onto the rotating motor
○ Disabled with manual restart required
NOTE An automatic restart puts a pump or a fan back in service without an operator, which a remote station or a process that must not stop wants, and it restarts a machine nobody is watching, which a plant with people near the driven equipment or a process that must be sequenced back into service does not; the flying restart that makes the automatic restart safe for the machine measures the residual rotation first and resumes at that speed. Which a project wants follows from the process, so this field carries no default. (11.3.5)
11.3.6 Where automatic restart is enabled, the restart delay, the number of attempts, and the attempt window shall be adjustable, the drive shall lock out after the configured number of attempts, and the restart shall be reconciled with the sequence of operations of the controller under Programmable Logic ControllersProgrammable Logic ControllersResolves to the current adopted revision.sync/programmable-logic-controllers so that the drive and the controller do not command conflicting restarts.

12 Cooling

12.1 Cooling Method

12.1.1 The cooling method of the lineup shall be as indicated in the datasheet.
Cooling Methodradio
○ Air-cooled
○ Liquid-cooled with a heat exchanger
NOTE An air-cooled lineup draws room air through its power cells and its transformer with redundant fans and puts every watt it loses, two to four percent of the drive's rating, into the room, which the room's ventilation or cooling then has to carry away; it is the arrangement of nearly every drive through a few thousand horsepower and needs nothing but a room that can take the heat. A liquid-cooled lineup circulates a deionized coolant through the power cells and rejects the heat through a heat exchanger to the outdoors or to plant water, so the room carries a fraction of the loss, the lineup is smaller and quieter, and the power cells run cooler; it brings a pump, a coolant loop, a deionizer, and a heat exchanger to maintain, and it is bought where the rating is large, the room is small or hot, or the heat is worth recovering. (12.1.2)
12.1.3 Where air cooling is selected, the lineup shall be furnished with redundant cooling fans arranged so that the drive carries its rated output with any one fan out of service, with a fan failure alarmed at the operator interface, and with every fan replaceable from outside the enclosure or from the front of the lineup without de-energizing the drive.
12.1.4 Where air cooling is selected, the air intake shall be furnished with replaceable filter media accessible without de-energizing the drive, and the drive shall alarm a differential pressure across the filter that indicates a fouled filter.
12.1.5 Where air cooling is selected, the discharge arrangement of the cooling air shall be as indicated in the datasheet.
Cooling Air Dischargeradio
● Discharged into the room
○ Ducted from the lineup to the outdoors or to a return plenum
NOTE A ducted discharge takes the drive's losses out of the room through a plenum bolted to the top of the lineup, so the room's cooling is sized for the people and the other equipment rather than for the drive, at the cost of a duct, a damper, and a fan arrangement the mechanical trade designs and the drive's fans are selected for. Where several large drives share one room, the duct is what keeps the room from being sized by the drives. (12.1.6)

12.2 Liquid Cooling System

NOTE Requirements in this article apply where the datasheet selects liquid cooling. (12.2.1)
12.2.2 The liquid cooling system shall be furnished by the drive manufacturer as part of the lineup, with redundant coolant pumps, a deionizer, a coolant conductivity monitor, a flow switch, a leak detector in every section carrying coolant, and a coolant temperature control, each alarmed at the operator interface.
12.2.3 The heat rejection of the liquid cooling system shall be as indicated in the datasheet.
Liquid Cooling Heat Rejectionradio
○ Liquid-to-air heat exchanger furnished with the lineup
○ Liquid-to-liquid heat exchanger to plant cooling water
○ Liquid-to-air heat exchanger mounted outdoors
NOTE A liquid-to-air exchanger in the lineup rejects the heat to the room through its own fans, so the room still carries the loss and the gain is cooler power cells and a smaller enclosure; a liquid-to-liquid exchanger passes the heat to plant cooling water, which removes it from the room entirely and depends on that water being available, clean, and at a temperature the exchanger was sized for whenever the drive runs; an outdoor liquid-to-air exchanger removes the heat from the building through a coolant loop to a remote unit, which the mechanical trade routes and insulates and which freezes in winter unless the loop is protected. (12.2.4)
12.2.5 Where a liquid-to-liquid heat exchanger is selected, the plant cooling water flow, temperature, pressure, and quality at the exchanger shall be as indicated on the mechanical equipment schedules, and the drive manufacturer shall confirm in the submittal that the exchanger is sized for them.
12.2.6 Where any part of the coolant loop is outdoors or in an unconditioned space, the coolant shall be protected against freezing at Site Ambient Temperature MinimumSite Ambient Temperature MinimumParameterEach project supplies its own value.site-ambient-temperature-minimum.
12.2.7 The drive shall reduce its output or shall stop, as the manufacturer states in the product data, on loss of coolant flow, on coolant conductivity above the manufacturer's limit, or on coolant temperature above the manufacturer's limit, and each condition shall be alarmed before the drive acts on it.

13 Enclosure

13.1 Enclosure Type

13.1.1 The enclosure type of the lineup shall be as indicated in the datasheet.
Enclosure Typeselect
Type 1 ventilated
Type 1 gasketed with filtered intake
Type 12 with a closed-loop air-to-air heat exchanger
Type 3R non-walk-in outdoor enclosure
Type 3R walk-in outdoor housing
NOTE A dry, conditioned electrical room is where a medium-voltage drive stands on nearly every project, and a ventilated Type 1 enclosure is the construction built for it; the gasketed and filtered construction keeps out the dust of an unconditioned plant space while still breathing room air; a Type 12 enclosure is sealed and cooled through an air-to-air heat exchanger or a liquid loop, which is the construction of a drive standing in a dusty or corrosive process area; a Type 3R enclosure is the outdoor construction, and a walk-in housing puts the working space in front of the lineup inside a weatherproof aisle so that it can be operated and serviced in any weather, at the cost of a structure, while a non-walk-in enclosure's working space is the pad in front of it. (13.1.2)
13.1.3 Where the lineup is installed outdoors, the enclosure shall be Type 3R at minimum, with rain hoods over every ventilation opening, a drip shield over every door, thermostatically controlled space heaters in every section, and lighting and a convenience receptacle in a walk-in housing.
13.1.4 Where the lineup is installed in a space subject to dust, dripping liquid, or a corrosive atmosphere, the enclosure shall be Type 1 gasketed with filtered intake at minimum, and Type 12 where the atmosphere carries conductive dust or corrosive vapor.
13.1.5 Where the lineup is installed within reach of salt air, chemical fallout, or de-icing spray, the enclosure shall be of a corrosion-resistant construction the manufacturer certifies for that exposure, and the finish shall be stated in the product data.
NOTE A medium-voltage drive breathes more air than any other piece of electrical equipment in the room, and a filter or a heat exchanger is the only thing between the room's dust and a power cell at several kilovolts. The enclosure type is the decision that sets what the drive breathes, and the cooling method under Cooling sets how much. (13.1.6)

13.2 Enclosure Construction and Access

13.2.1 The lineup shall be a dead-front, metal-enclosed, free-standing assembly with every medium-voltage compartment barriered from every low-voltage control compartment, with the control compartment accessible with the drive energized and the medium-voltage compartments accessible only with the input isolated, the stored energy discharged, and the interlocks under Input Section satisfied.
13.2.2 Every door giving access to a medium-voltage compartment shall be interlocked with the input isolation so that it cannot be opened with the input closed, and the input cannot be closed with the door open, with a tool-operable defeat for authorized testing, in accordance with the access provisions NFPA 70 requires for equipment over 1000 V.
13.2.3 Each medium-voltage compartment shall be furnished with a capacitive voltage indicator visible with the door closed, showing the presence of voltage on each phase.
13.2.4 The lineup shall be furnished with a ground bus running its full length, bonded to every section, to the input transformer enclosure or tank, and to every output filter and bypass section, with a ground connection point at each end sized for the grounding electrode conductor as indicated on the grounding details.
13.2.5 The finish system and color of the painted steel enclosure shall be as indicated in the datasheet.
Enclosure Finish Colorselect
ANSI 61 light gray
ANSI 49 medium gray
ANSI 70 sky gray
Custom color matched to a sample furnished by the Owner
NOTE ANSI 61 is the color of indoor electrical equipment and the color the drive, the switchgear beside it, and the motor control centers in the same room are finished in unless a plant standard says otherwise, so the lineup in that color reads as part of the room; the other grays are plant standards and a custom color is matched where the Owner's fleet carries one. (13.2.6)
13.2.7 The manufacturer shall state the finish system and its dry film thickness in the product data, and a separately mounted input transformer shall be finished to match the lineup.

13.3 Arc-Resistant Construction

13.3.1 Arc-resistant construction of the lineup shall be as indicated in the datasheet.
Arc-Resistant Constructionselect
Not required
Type 1 accessibility per IEEE C37.20.7
Type 2 accessibility per IEEE C37.20.7
NOTE Arc-resistant construction directs the products of an internal arcing fault away from the front of the lineup, and Type 2 extends that protection to the sides and the rear; on a medium-voltage lineup the incident energy is high enough that arc-resistant construction is often what brings the labeled personal protective equipment category to a workable level at the operator interface, and it adds a plenum, reinforced doors, and pressure-relief flaps that raise the height and the cost of the lineup and that must discharge somewhere the room can accept. It is offered on some drive platforms and not on others, and the input section is the part of the lineup most often built to it where the power cells are not. (13.3.2)
13.3.3 Where arc-resistant construction is selected, the lineup shall have been tested to IEEE C37.20.7 in the configuration furnished, the manufacturer shall state in the product data which sections of the lineup the tested protection covers, and the exhaust plenum and its discharge location shall be shown on the shop drawings and coordinated with Electrical RoomsElectrical RoomsResolves to the current adopted revision.sync/electrical-rooms.
NOTE Arc-resistant construction does not lower the incident energy at a section whose door is open, and the boundary of the tested protection is the boundary between the sections it covers and the sections it does not, which on a drive lineup is a line the manufacturer draws rather than one the room can see. (13.3.4)

14 Input Section

14.1 Input Isolation and Fusing

14.1.1 The input isolation of the drive shall be as indicated in the datasheet.
Input Isolationselect
Integral fused isolating switch
Integral medium-voltage vacuum contactor with current-limiting fuses
Upstream feeder circuit breaker alone
NOTE An integral fused isolating switch gives a visible, lockable break at the drive with current-limiting fuses that protect the input transformer and the rectifier, and it is operated with the drive stopped and the upstream breaker open, so it isolates and protects but does not switch; an integral vacuum contactor with fuses adds a switching device the drive control operates, which disconnects the drive on a fault without tripping the upstream breaker, gives the bypass a contactor to transfer through, and brings a controller under UL 347 into the lineup; the upstream feeder breaker alone leaves isolation and protection to the switchgear under Medium Voltage SwitchgearMedium Voltage SwitchgearResolves to the current adopted revision.sync/medium-voltage-switchgear, which is the smallest input section and depends on that breaker being dedicated to the drive, reachable to lock out, and relayed to protect the transformer. The choice follows from how the drive will be isolated for the cell replacement its maintenance consists of, and from whether a bypass needs a contactor, so this field carries no default. (14.1.2)
14.1.3 Where an integral fused isolating switch is selected, it shall be a three-pole, gang-operated, load-interrupter or non-load-break switch as the manufacturer's listing provides, with a viewing window through which the position of every blade can be verified with the door closed, mechanical position indication at the handle, a handle lockable in the open and closed positions accepting not fewer than three padlocks, and, where the switch is not rated for load-break duty, an interlock with the upstream breaker so that the switch cannot be operated with the breaker closed.
14.1.4 Where an integral vacuum contactor is selected, it shall comply with UL 347, shall be rated for the drive's input current and for the fault-closing duty established under Short-Circuit Current Rating, and shall be protected by current-limiting fuses coordinated by the manufacturer to protect the contactor and the input transformer, with the fuse ratings stated in the submittal and not changed in the field.
14.1.5 Where the upstream feeder circuit breaker alone is selected, the Contractor shall confirm that the breaker shown on the one-line diagram is dedicated to the drive, is lockable open, and is relayed to protect the input transformer, and shall report any shortfall to the Engineer of Record before the drive is released for manufacture.
14.1.6 Where current-limiting fuses are furnished in the input section, each fuse shall carry a blown-fuse indicator visible with the door closed, and the drive shall trip and alarm on a blown fuse so that the input transformer does not run single-phased.
14.1.7 The input section provisions shall be as indicated in the datasheet.
Input Section Provisionscheckbox
☐ Integral grounding switch, interlocked with the input isolation and the upstream breaker
☑ Key interlock with the upstream feeder breaker
☑ Metal-oxide surge arresters at the incoming terminals
☑ Capacitive voltage indicators on the incoming terminals
☐ Infrared inspection windows at the incoming cable terminations
☐ Input current and voltage metering displayed at the operator interface
NOTE A grounding switch grounds the de-energized input bus and the transformer winding before cell replacement begins and depends on its interlocks to keep it off an energized bus; a key interlock with the upstream breaker makes the drive's isolation and the breaker's lockout one procedure; surge arresters protect the transformer winding and the rectifier against surges arriving on the supply cable, with protective margin applied per IEEE C62.22; capacitive voltage indicators give the person at the door a check of the bus state before the interlocks are defeated for testing. (14.1.8)

14.2 Incoming Connection

14.2.1 The incoming connection to the lineup shall be as indicated in the datasheet.
Incoming Connectionradio
● Shielded cable terminated in an incoming cable compartment
○ Medium-voltage bus duct through an entry flange furnished with the lineup
NOTE A cable connection is the connection of nearly every drive, because the feeder from the switchgear is a cable and the drive stands where the cable can reach; a bus duct connection receives a medium-voltage bus duct under Medium Voltage Bus DuctMedium-Voltage Metal-Enclosed BusResolves to the current adopted revision.sync/medium-voltage-bus-duct from switchgear that stands close by, through a flange the drive manufacturer furnishes and the bus duct manufacturer mates to, and it is bought where the drive's input current is higher than cable serves economically or where the room has no route for a cable. (14.2.2)
14.2.3 Where a cable connection is selected, the incoming cable compartment shall be sized to receive the number and size of supply cables as indicated on the one-line diagram and the conduit and cable schedule, with space to make up a termination on each cable without bending the cable below its minimum radius, and the terminations shall comply with Medium Voltage CablesMedium-Voltage CablesResolves to the current adopted revision.sync/medium-voltage-cables.
14.2.4 The incoming cable compartment shall be furnished with a grounding provision for the cable shields and for a portable grounding set, and with a barrier between the cable compartment and the switch, contactor, or transformer compartment.
14.2.5 Where a bus duct connection is selected, the drive manufacturer shall furnish the entry flange, the bus stubs, and the flexible connectors at the lineup, rated for the lineup's continuous current and short-circuit current rating, and shall furnish the certified flange drawing to the bus duct manufacturer before either is released for manufacture.
14.2.6 The incoming cable entry shall be as indicated in the datasheet.
Cable Entryradio
○ Top entry
○ Bottom entry
○ Top and bottom entry
Per drawings — the electrical plans (deferred by default)

15 Bypass

15.1 Bypass Arrangement

15.1.1 The bypass arrangement shall be as indicated in the datasheet.
Bypass Arrangementselect
No bypass
Contactor bypass, full-voltage across the line
Contactor bypass through a medium-voltage reduced-voltage solid-state starter
Synchronous transfer of several motors between the drive and the line
NOTE No bypass is the arrangement of most medium-voltage drives, because a drive failure on a station with a standby pump or a fan with a spare is a maintenance event, and a bypass preserves none of the reason the drive was bought. A full-voltage contactor bypass puts the motor across the line through an output contactor and a bypass contactor, so the motor runs at one speed when the drive is out, and every bypass start is an across-the-line start of a medium-voltage motor, with the inrush, the voltage dip, and the mechanical shock that implies, which the supply and the driven machine have to tolerate. A bypass through a reduced-voltage solid-state starter adds a thyristor starter in the lineup that ramps the motor to full speed in bypass, which limits the inrush and the shock at the cost of a second medium-voltage controller and its own protection. A synchronous transfer scheme uses one drive to start several motors in turn, synchronizing each to the line and transferring it across with no inrush, then picking up the next; it is the arrangement of a station with several large pumps of which one at a time is speed-controlled and the rest run at full speed, and it is a controls and switching scheme the drive manufacturer engineers for the project. The choice follows from what the plant needs the motor to do when the drive is out and from how many motors share the drive, so this field carries no default. (15.1.2)
15.1.3 Where a bypass is selected, the output contactor, the bypass contactor, and the reduced-voltage starter where one is furnished shall comply with UL 347, shall be furnished by the drive manufacturer as sections of the lineup, and shall be rated for the motor's full-load current, its locked-rotor current for the duration of an across-the-line or reduced-voltage start, and the fault-closing duty established under Short-Circuit Current Rating.
15.1.4 Where a bypass is selected, mechanical and electrical interlocks shall prevent the drive output contactor and the bypass contactor from being closed at the same time, and the interlock arrangement shall fail so that a control failure or a wiring error cannot connect the line to the drive output terminals.
15.1.5 Where a bypass is selected, the motor shall be protected in bypass by a motor protection relay independent of the drive, set for the motor's across-the-line full-load current, and the relay's trip shall open the bypass contactor.
NOTE The drive's protection is in the drive's output path and does nothing once the motor is fed from the bypass contactor, so the bypass circuit needs its own protection, set for across-the-line current rather than for the current the motor draws at part speed. Where a separate motor protection relay is selected under Motor Protection, one relay serves both paths; where the drive's integral protection is selected, the bypass brings the relay the drive did not. (15.1.6)
15.1.7 Where a synchronous transfer scheme is selected, the drive manufacturer shall furnish the output contactors, the line contactors, the synchronizing control, and the sequence for every motor in the scheme, shall state the transfer sequence in the submittal, and shall demonstrate every transfer and every retransfer at startup.

15.2 Bypass Transfer Control

15.2.1 Where a bypass is selected, the bypass transfer initiation shall be as indicated in the datasheet.
Bypass Transfer Initiationselect
Not applicable, no bypass
Manual transfer by operator selection at the lineup
Automatic transfer on drive fault with manual return to drive operation
Automatic transfer on drive fault with automatic return to drive operation
NOTE A manual transfer leaves the decision to put a medium-voltage motor across the line to a person, who can confirm that the supply, the machine, and the process will take the start; an automatic transfer on fault keeps the process running without that person, at the cost of an unattended across-the-line start whenever the drive trips; a manual return keeps the motor in bypass until someone has looked at the fault, and an automatic return puts the drive back in service unattended, which on an intermittent fault cycles the motor between the two with an across-the-line start each time. The choice follows from whether the process can wait for a person and whether the machine can take a repeated start, so this field carries no default. (15.2.2)
15.2.3 Where automatic transfer is selected, the transfer shall wait for the motor to coast to a standstill or shall be synchronized to the rotating motor as the manufacturer's scheme provides, and the drive shall report the fault and the bypass status to the controller as separate points.
15.2.4 Where a manual return is selected, return from bypass to drive operation shall require a reset at the lineup after the fault has been cleared.

16 Motor Protection and Protective Functions

16.1 Motor Protection

16.1.1 The motor protection shall be as indicated in the datasheet.
Motor Protectionradio
○ Integral to the drive, with the drive's thermal model and its motor temperature inputs
○ Separate multifunction motor protection relay in the lineup
NOTE The drive's integral protection models the motor's heating from the current it supplies, accepts the motor's temperature sensors, and trips the drive, which protects the motor whenever the drive is feeding it and nothing else; a separate multifunction relay measures the motor circuit with its own current transformers, protects the motor in bypass as well as on the drive, carries the differential, ground, and starts-per-hour functions a large motor's protection scheme is built around, and trips the input contactor or the upstream breaker rather than the drive alone, at the cost of the relay, its instrument transformers, and its settings. A drive with no bypass on a motor the plant does not treat as critical runs on the drive's protection; a large or critical motor, a motor with a bypass, or a plant whose protection scheme is relay-based carries the relay. (16.1.2)
16.1.3 Where the drive's integral protection is selected, it shall provide motor thermal overload protection with a thermal model compensated for reduced motor cooling at low speed and retained through a power cycle, motor overcurrent and ground fault protection, phase unbalance protection, stall protection, and inputs for not fewer than six motor winding and bearing resistance temperature detectors with an alarm and a trip level for each.
16.1.4 Where a separate motor protection relay is selected, it shall provide the functions indicated in the datasheet.
Motor Protection Relay Functionscheckbox
☑ Thermal overload (49) with resistance temperature detector inputs
☑ Phase overcurrent (50/51)
☑ Ground overcurrent (50G/51G)
☑ Phase unbalance and negative sequence (46)
☑ Locked rotor and acceleration time (48/51LR)
☐ Loss of load (37)
☑ Starts per hour and restart inhibit (66)
☐ Motor differential (87M)
16.1.5 Where a separate motor protection relay is selected, its current transformers shall be furnished in the lineup on the drive output or on the motor circuit so that the relay measures the motor current on the drive and in bypass alike, and its settings shall be applied from the coordination study performed under Protective Coordination StudyProtective Device Coordination StudyResolves to the current adopted revision.sync/protective-coordination-study.
NOTE Where the feeder breaker in the switchgear under Medium Voltage SwitchgearMedium Voltage SwitchgearResolves to the current adopted revision.sync/medium-voltage-switchgear is relayed to protect the motor, the motor protection functions in that switchgear are that standard's; where the drive protects the motor, by its integral protection or by a relay in the lineup, the functions are this standard's. A motor protected from both places is protected by two relays set against each other, and the one-line diagram is where the split is drawn. (16.1.6)
16.1.7 The Contractor shall confirm with the Engineer of Record which arrangement the one-line diagram shows before the motor protection settings are submitted, so that the motor is protected once.

16.2 Drive Protective Functions

16.2.3 The drive shall distinguish an alarm, under which the drive keeps running and reports the condition, from a trip, under which it stops, and the manufacturer shall state in the product data which conditions produce each and which thresholds are adjustable.
NOTE An output ground fault on a medium-voltage motor circuit is the fault the drive sees first, because the drive's output is not referenced to ground the way the supply is, and a drive that trips on it protects a winding that a relay on the input would never see. The fault record with the operating snapshot is what separates a cooling failure from a fouled filter from a room that ran hot, after the fact and without reproducing the condition. (16.2.4)

17 Control Power, Operator Interface, and Communications

17.1 Control Power

17.1.1 The control power source of the drive shall be as indicated in the datasheet.
Control Power Sourceradio
○ Derived within the lineup from the input transformer or an integral control power transformer
○ External 120 V source backed by an uninterruptible power supply
○ External 125 V DC station battery
NOTE Control power derived within the lineup needs no external circuit and is lost whenever the input is lost, so the drive's control, its fans, and its fault record are alive only while the supply is; an external uninterruptible 120 V source keeps the control alive through a supply loss, which is what a ride-through of more than a few tenths of a second and an automatic restart after a supply loss depend on, and it is the source a plant with a control UPS brings to every drive; a 125 V DC station battery under DC Battery SystemsDC Battery SystemsResolves to the current adopted revision.sync/dc-battery-systems does the same from the battery that serves the switchgear and the relays, and is the source a power plant or a substation-grade installation standardizes on. The choice follows from what the plant has and what it needs the drive to do when the supply is lost, so this field carries no default. (17.1.2)
17.1.3 Where control power is derived within the lineup, the drive shall sustain its control through a supply interruption of not less than the ride-through duration selected under Power Loss Ride-Through and Restart from stored energy within the lineup.
17.1.4 Where an external control power source is selected, the lineup shall be furnished with a terminal block for the external circuit, a control power transfer or a redundant supply that keeps the control alive on loss of either source where the manufacturer's design provides one, and a loss-of-control-power alarm.
17.1.5 The space heaters, the lighting of a walk-in housing, and the liquid cooling system auxiliaries shall be supplied from a source that stays energized with the drive input open, separate from the drive control power where the drive control is derived within the lineup.

17.2 Operator Interface

17.2.1 Each drive shall include a door-mounted operator interface, accessible with every medium-voltage door closed, that provides operating data, the fault history, every parameter, and local start, stop, speed, and reset without an external device.
17.2.3 The operator interface shall provide a local-off-remote selection, with the off position lockable so that the drive can be secured off without operating the input isolation, and the drive shall report the selected mode to the controller.
17.2.4 Parameter access shall be protected by not fewer than two password levels, separating the operator's daily access from the settings that carry design intent, and the passwords in effect at substantial completion shall be delivered to the Owner with the closeout submittals.

17.3 Hardwired Inputs and Outputs

17.3.1 Each drive shall provide not fewer than two analog inputs, one analog output, eight programmable digital inputs, and four programmable Form C relay outputs, each wired to a terminal block in the low-voltage control compartment.
17.3.2 The speed reference signal shall be as indicated in the datasheet.
Speed Reference Signalselect
4–20 mA current loop
0–10 V DC
Speed commanded over the network
Internal process controller from a local transmitter
NOTE A 4–20 mA loop carries a live zero, so an open conductor reads as a loss of signal rather than as a zero-speed command, and it is immune to the voltage drop a long run from the control panel imposes on a voltage reference; a network reference removes the analog signal and its wiring and leaves the drive to follow a command whose loss is handled under Loss of Communication Response; an internal process controller closes the loop in the drive from a transmitter wired to it, which keeps the loop running when the network or the controller does not and is the fallback a drive that must keep a tank level or a header pressure on its own uses. The choice follows from the control architecture under Programmable Logic ControllersProgrammable Logic ControllersResolves to the current adopted revision.sync/programmable-logic-controllers, so this field carries no default. (17.3.3)
17.3.4 The fault relay output shall be wired in a normally energized, de-energize-on-fault arrangement so that a loss of control power raises the same alarm a fault does.
17.3.5 The drive shall provide a hardwired emergency stop input, independent of the network and of the operator interface, that stops the drive and opens the output contactor where one is furnished, and a hardwired run-permissive input from the driven equipment's protective devices.

17.4 Network Communications

17.4.1 The network communication protocol of the drive shall be as indicated in the datasheet.
Network Communication Protocolselect
EtherNet/IP
Modbus TCP
PROFINET
PROFIBUS DP
Modbus RTU
IEC 61850
DeviceNet
Hardwired only, no network interface
NOTE The protocol is fixed by the controller and the network the drive reports to under Programmable Logic ControllersProgrammable Logic ControllersResolves to the current adopted revision.sync/programmable-logic-controllers and Process Control NetworksProcess Control NetworksResolves to the current adopted revision.sync/process-control-networks rather than by the drive: EtherNet/IP and PROFINET are the protocols of the two controller families most plants are built on, Modbus TCP and Modbus RTU are what nearly every drive and every controller speak when nothing else is shared, PROFIBUS DP and DeviceNet persist on plants built around them, and IEC 61850 is the protocol of a substation-grade installation whose relays and switchgear already speak it. A hardwired-only drive is the drive of a station with no network or one whose Owner keeps the drive off it. Which one a project needs follows from the network it already has, so this field carries no default. (17.4.2)
17.4.4 The drive shall accept over the network, as commands, start and stop, the speed reference, fault reset, and, where a bypass is furnished, the bypass transfer where the datasheet selects a transfer the controller initiates.
17.4.5 The network cable, its routing, and its separation from power conductors shall comply with Process Control NetworksProcess Control NetworksResolves to the current adopted revision.sync/process-control-networks and Instrumentation And Control CableInstrumentation and Control CableResolves to the current adopted revision.sync/instrumentation-and-control-cable, and the network interface shall be brought to a connector in the low-voltage control compartment.

17.5 Loss of Communication Response

17.5.1 The drive response to loss of network communication shall be as indicated in the datasheet.
Loss of Communication Responseselect
Maintain the last commanded speed
Run at a programmed fixed speed
Ramp to minimum speed
Stop the drive
Transfer to the internal process controller
NOTE A network failure, a controller reboot, and a controller isolated for maintenance look alike to the drive, and they are all common; what differs is the consequence of each response on the process. Holding the last speed keeps the flow while the loop stops correcting, which suits a pump whose demand changes slowly; a fixed speed puts the machine at a known safe point; ramping to minimum keeps the machine turning while removing most of its effect; stopping removes the load entirely and is the response where an uncontrolled machine is worse than a stopped one; a transfer to the internal controller keeps the controlled variable on setpoint provided a local transmitter exists. The choice follows from the process, so this field carries no default. (17.5.2)
17.5.3 The communication loss timeout shall be adjustable, shall be set at startup, and shall be reconciled with the sequence of operations of the controller so that the drive and the controller do not act on the same failure in conflicting ways, and the drive shall alarm the loss at the operator interface and on the fault relay.

18 Testing

18.1 Factory Testing

18.1.1 Every drive shall receive the production tests of IEEE 1566 and of its listing or certification before shipment, including as a minimum a dielectric withstand test of every medium-voltage circuit, an insulation resistance measurement of the input and output circuits, the routine tests of IEEE C57.18.10 on the input transformer, a functional test of the control through acceleration to rated speed and controlled deceleration to stop, a test of every protective function by simulated fault, a test of every interlock, a test of the cooling system and of every cooling alarm, a functional test of the network interface, and a visual and dimensional inspection, with a certified report for each unit.
18.1.2 The factory test regime shall be as indicated in the datasheet.
Factory Test Regimeradio
○ Production tests with a certified test report
○ Witnessed factory test of the drive on a factory load
○ Witnessed factory string test of the drive with the project motor
NOTE A certified report records the production tests without a trip; a witnessed test on a factory load lets the Owner see the drive run, every protective function trip, and the bypass sequence operate before it ships, at the cost of travel and a schedule hold; a string test couples the drive to the motor it will drive, so the output waveform, the motor's temperature rise on that waveform, the torsional response of the train where a load is coupled, and the drive's tuning to that motor are proven at the factory rather than at the plant, at the cost of shipping the motor to the drive factory or the drive to the motor factory and of the test bay time the motor manufacturer prices. A string test is called for where the motor is large or unusual, where the train has a torsional analysis to confirm, where the topology and the motor have not run together before, or where a failure found at the plant would be found on the critical path. (18.1.3)
18.1.4 Where a witnessed test is selected, the manufacturer shall give the Owner not less than two weeks' notice of test readiness, the test procedure shall have been submitted and returned before the test date, and the drive shall not ship until the witness has accepted the results or has waived attendance in writing.
18.1.5 Where a witnessed test is selected, the Owner shall bear the cost of its own and the Engineer of Record's travel and attendance, and the Contractor shall bear the cost of the test, of the motor's shipment and test bay time for a string test, and of any retest following a failure.
18.1.6 Where a string test is selected, the test shall run the drive and the motor at rated speed under the load the test bay can apply for not less than two hours, shall record the motor's temperature rise, the peak voltage and rise time at the motor terminals, and the common-mode voltage, and shall exercise every speed in the operating range to identify the resonant speeds of the train as mounted at the factory.
18.1.7 The manufacturer shall retain production test records for not less than ten years and shall furnish them to the Owner on request.

18.2 Field Acceptance Testing

18.2.1 Field acceptance testing shall be performed after the lineup is installed and before it is energized, in accordance with ANSI/NETA ATS and with Electrical Acceptance TestingElectrical Acceptance TestingResolves to the current adopted revision.sync/electrical-acceptance-testing, which governs the testing firm, the instruments, the acceptance criteria for the electrical tests, and the report, and the lineup shall receive the tests indicated in the datasheet.
Field Acceptance Testscheckbox
☑ Adjustable speed drive system inspection and tests per ANSI/NETA ATS Section 7.17, with the power electronics isolated for the insulation tests
☑ Dry-type input transformer tests per ANSI/NETA ATS Section 7.2.1.2, or liquid-filled transformer tests per Section 7.2.2 for a separately mounted liquid-immersed unit
☑ Medium-voltage metal-enclosed air switch tests per ANSI/NETA ATS Section 7.5.1.2 on an integral fused isolating switch
☑ Medium-voltage motor starter tests per ANSI/NETA ATS Section 7.16.1.2 on the integral contactor and on the bypass controller
☑ Protective relay tests per ANSI/NETA ATS Section 7.9 on a separate motor protection relay
☐ Instrument transformer tests per ANSI/NETA ATS Section 7.10 on the current and voltage transformers in the lineup
☑ Torque or contact-resistance verification of every bolted connection in the lineup and in every throat
☑ Insulation resistance of the input bus, the output bus, and the output filter with the power cells isolated
☑ Functional test of every door, key, and electrical interlock in every combination
☑ Functional test of every protective function by simulated fault, with the as-left settings recorded
☐ Functional test of the bypass through every transfer and retransfer with the contactors operated
☑ Verification of every protective setting against the coordination study
☐ Measurement of current and voltage distortion at the compliance point with the drive at the highest load the process can apply
18.2.2 Insulation resistance and dielectric tests shall be performed with the power cells, the control boards, and every surge arrester isolated or removed as the manufacturer's instructions direct, and no test voltage shall be applied through the power electronics.
18.2.3 The motor cable shall be tested under Medium Voltage CablesMedium-Voltage CablesResolves to the current adopted revision.sync/medium-voltage-cables with the cable disconnected from the drive output terminals, and shall not be tested through the drive or the output filter.
NOTE A test voltage applied through a power cell finds the cell's semiconductors before it finds the insulation, and a drive that arrives in working order is turned into a drive with failed cells by the test meant to prove it. The isolation of the electronics is the one instruction on this class that the testing firm has to hear from the manufacturer rather than from the test standard. (18.2.4)
18.2.5 A lineup, a section, or a function that fails an acceptance test shall be corrected and retested, and the cost of the correction and the retest, including the cost of the Engineer of Record's attendance at the retest, shall be borne by the Contractor.
18.2.6 No section of the lineup shall be energized until the field acceptance tests covering it have passed, the arc-flash labels have been installed, and the testing firm has released it for energization under Electrical Acceptance TestingElectrical Acceptance TestingResolves to the current adopted revision.sync/electrical-acceptance-testing.

18.3 Field Startup

18.3.1 Initial energization, the motor identification or auto-tune procedure, parameter programming to the project sequence of operations, and the first run of the motor shall be performed by a technician trained and authorized by the drive manufacturer, with the Contractor's electrician, the controls integrator, and the driven equipment manufacturer's representative present.
18.3.2 Before energizing any drive, the technician shall verify that every shipping brace, block, and desiccant has been removed, that every field termination has been torqued to the manufacturer's values, that the supply voltage at the input terminals is within 3 percent of nominal and within 2 percent between phases, that the motor nameplate data match the drive parameters, that the cooling system runs and every cooling alarm clears, and that the stored-energy discharge indication operates.
18.3.3 The lineup shall be energized from the supply with the output contactor open or the motor disconnected, held while the input transformer sound level, the temperatures, and the control are observed, and the motor shall then be run uncoupled from the driven machine where the machine permits, at low speed, to confirm rotation before it is run coupled.
18.3.4 Startup shall run the coupled train at the lowest operating speed, at not fewer than two intermediate speeds, and at the highest operating speed, shall record the motor current, voltage, and speed and the drive's temperatures at each point, shall sweep the operating range to identify every speed at which the train or its piping or structure resonates, and shall program each as a skip band before the drive is placed in service.
18.3.5 Startup shall set the acceleration and deceleration ramps for the installed load, shall demonstrate the ride-through and the restart behavior selected, shall demonstrate every bypass transfer and retransfer where a bypass is furnished, and shall verify every network monitored point and every network commanded point with the controls integrator present.
18.3.6 Where the datasheet selects a compliance point, the technician shall measure the current and voltage distortion there with the drive at the highest load the process can apply and shall record the measurement in the startup report against the limits of this standard.
NOTE Startup and controls integration are the same event seen from two trades: a drive programmed without a controller to answer it, and a controller pointed at a drive nobody can reprogram that day, are resolved on a return visit that one scheduled day avoids. (18.3.7)

18.4 Training

18.4.1 The drive manufacturer shall provide training for the Owner's operating and maintenance personnel at the site, in not fewer than two sessions of not less than four hours each, one for operators covering the operator interface, the modes, the alarms and faults, and the bypass, and one for maintenance personnel covering the isolation and grounding procedure, the stored-energy discharge, the power cell replacement, the cooling system maintenance, the filter and fan replacement, the fault history, and the parameter backup and restore.
18.4.2 The maintenance session shall include a demonstration of the isolation, discharge verification, and cell removal and replacement procedure on the installed lineup with the drive de-energized, and each attendee shall perform the discharge verification.
18.4.3 The training shall be scheduled within 30 days after startup, at a date the Owner selects, and the manufacturer shall furnish the training material to each attendee and a copy for the operation and maintenance data.

19 Installation

19.1 Room and Pad

19.1.1 An indoor lineup shall be installed in a room complying with Electrical RoomsElectrical RoomsResolves to the current adopted revision.sync/electrical-rooms, and the room ventilation or cooling shall carry away the heat rejected to the room stated in the ratings sheet, with the drive at rated load, so that the room ambient does not exceed the indoor design ambient temperature selected in the datasheet.
19.1.2 The lineup shall be set on a concrete pad constructed under Concrete PadsConcrete Equipment PadsResolves to the current adopted revision.sync/concrete-pads, of the height indicated in the datasheet, extending not less than 3 in. beyond the lineup base on every side, and level across its full length so that the sections align at the throats without shimming beyond the manufacturer's stated limit.
Housekeeping Pad Heightrange
in.
346
NOTE A pad keeps the base of the lineup above a wet floor and gives the anchors something to bite into that is not the slab's reinforcing; a pad height of zero is the direct-to-slab installation used where the floor is a structural slab designed for the anchors, and an outdoor lineup stands on a pad whose height the site grading sets. (19.1.3)
19.1.4 The lineup shall be anchored to the pad as indicated on the seismic anchorage details, and where seismic qualification is required the anchorage shall be that on which the qualification depends.
19.1.5 The Contractor shall confirm the pad dimensions, the conduit stub-up locations, the anchor locations, the coolant connection locations where liquid cooling is selected, and the weight of each shipping section against the reviewed shop drawings before the pad is placed, and shall report a discrepancy to the Engineer of Record before concrete is placed.

19.2 Working Space and Clearances

19.2.1 Working space in front of, behind, and beside the lineup where it is accessible there shall comply with NFPA 70 110.34 for the medium-voltage sections and NFPA 70 110.26 for the low-voltage control compartments, and the clearance the manufacturer requires to remove a power cell, to open every door fully, and to service the cooling system shall be maintained in addition.
19.2.2 The air intake and discharge of an air-cooled lineup shall be kept clear for the distance the manufacturer states, the lineup shall not be installed where its intake can draw its own discharge air or the discharge of other equipment, and the dedicated space above the lineup required by NFPA 70 110.26(E) shall be kept clear of piping, ductwork, and equipment not associated with the lineup.
19.2.3 Working space shall not be used for storage at any time.

19.3 Setting, Wiring, and Grounding

19.3.1 Shipping sections shall be set, aligned, and bolted together at the throat flanges in accordance with the manufacturer's instructions, the bus connection through each throat shall be made up with the manufacturer's hardware torqued to its values with a calibrated tool, and every shipping brace, block, and desiccant shall be removed before the lineup is energized.
19.3.2 The supply cable and its terminations shall comply with Medium Voltage CablesMedium-Voltage CablesResolves to the current adopted revision.sync/medium-voltage-cables, the motor cable with that standard and with the output cable conditions of this standard, the control and network conductors with Instrumentation And Control CableInstrumentation and Control CableResolves to the current adopted revision.sync/instrumentation-and-control-cable, and every raceway with Raceways And ConduitRaceways and ConduitResolves to the current adopted revision.sync/raceways-and-conduit, with the motor conductors in a raceway of their own.
19.3.3 Motor output conductors shall not share a raceway, wireway, or cable tray with the supply conductors, with another motor circuit, or with control or communication conductors.
19.3.4 The lineup ground bus shall be bonded to the grounding electrode system in accordance with NFPA 70 Article 250 and Grounding And BondingGrounding and Bonding for Electrical SystemsResolves to the current adopted revision.sync/grounding-and-bonding, a separately mounted input transformer shall be bonded to the lineup ground bus, and the motor frame shall be bonded to the lineup ground bus by a conductor routed with the motor cable in addition to the cable shields.
19.3.5 Every field termination shall be torqued to the device manufacturer's published value with a calibrated tool, and the torque values applied shall be recorded in the field test report.
19.3.6 The protective settings shall be applied in the field from the coordination study performed under Protective Coordination StudyProtective Device Coordination StudyResolves to the current adopted revision.sync/protective-coordination-study before the lineup is energized.

19.4 Identification

19.4.1 Nameplates shall be furnished on the lineup, on each section, on a separately mounted input transformer, and on each bypass contactor and reduced-voltage starter, and shall comply with Equipment LabelingElectrical Equipment LabelingResolves to the current adopted revision.sync/equipment-labeling for material, lettering, and attachment.
19.4.2 The lineup nameplate shall state the drive designation, the motor served and its horsepower and rated voltage, the supply voltage, the continuous output current and overload duty, the short-circuit current rating, the topology and pulse count, the source feeder designation, and the manufacturer and serial number.
19.4.3 Each medium-voltage compartment door shall carry a warning of the voltage within, the stored-energy hazard, and the discharge time before the compartment can be entered, and each bypass section shall carry a warning that the motor circuit is energized from the line with the drive isolated.
19.4.4 Arc-flash incident energy labels shall be applied to each section in accordance with NFPA 70 110.16 and NFPA 70E, with the values taken from the study performed under Arc Flash StudyArc-Flash Hazard AnalysisResolves to the current adopted revision.sync/arc-flash-study.

20 Delivery, Storage, and Handling

20.1 The lineup shall be shipped in the largest sections that the route from the delivery point to the final location will pass, with the shipping splits at the throat flanges, and the Contractor shall verify door, corridor, hoistway, and crane dimensions along that route before the shipping splits are fixed on the shop drawings.
20.2 Each shipping section shall be lifted only at the lifting provisions the manufacturer furnishes, and a liquid-immersed input transformer shall be lifted by its tank lifting lugs with a spreader that keeps the slings clear of the bushings.
20.3 The sections shall be stored indoors in a clean, dry location protected from construction dust and water until they are set, within the manufacturer's storage temperature range, with each throat flange covered, except that a liquid-immersed input transformer may be stored outdoors on its pad with its tank pressure maintained.
20.4 Where a section is stored for more than 30 days or in a space that is not conditioned, its space heaters shall be connected to a temporary supply and energized for the duration of storage.
20.5 Where the lineup is stored for longer than the manufacturer's stated limit before energization, the Contractor shall obtain the manufacturer's capacitor re-forming procedure and shall perform it under the manufacturer's supervision before energization, at the Contractor's cost.
20.6 A section that has been wetted in transit or in storage shall be dried, inspected by the manufacturer's field service organization, and released in writing before it is energized.
NOTE The power cell capacitors lose oxide layer thickness while sitting unenergized, and re-forming restores it under controlled voltage rather than letting the first energization do it as a fault; construction dust is the other storage hazard, because a filter that keeps room dust out of a running drive does nothing for a drive whose doors are open on a job site. (20.7)

21 Warranty

21.1 The manufacturer shall warrant the complete lineup, including the input transformer whether integral or separately mounted, every power cell, the cooling system, the output filter, and every factory-installed device, against defects in materials and workmanship for the period indicated in the datasheet.
Warranty Periodrange
years
1235
Default: Not less than 1 years
21.2 The warranty period shall commence on the date indicated in the datasheet.
Warranty Commencementselect
Date of substantial completion
Date of startup
Date of shipment
NOTE Warranty commencement at shipment is the manufacturer's usual term, and it consumes the warranty during storage and construction; commencement at startup or substantial completion moves the coverage to the period the Owner is operating the equipment, and the manufacturer prices the added months into the lineup. (21.3)
21.4 The warranty coverage scope shall be as indicated in the datasheet.
Warranty Coverage Scoperadio
○ Parts only
○ Parts and labor
21.5 A repair or replacement performed under this warranty shall itself be warranted for a full new term equal to the original period from the date the repair is completed, or for the remainder of the original period, whichever ends later.
21.6 The manufacturer shall bear the cost of removing and reinstalling equipment displaced to reach a warranted repair, and of repairing collateral damage caused by the failure or by the repair.
21.7 The warranty shall not cover damage resulting from installation contrary to the manufacturer's published instructions, from operation outside the rated supply, ambient temperature, or altitude limits without the derating this standard requires, from a motor whose insulation system does not carry the stress stated in the output-side analysis, or from modification of the drive hardware or firmware without the manufacturer's written authorization, and where the parties disagree whether a failure falls within an exclusion, the Engineer of Record shall make the initial determination.
21.8 The Contractor shall warrant the installation, including every field connection, the anchorage, the grounding, and the field-applied settings, for the project warranty period.

22 Spare Parts

22.1 The Contractor shall deliver the spare parts indicated in the datasheet to the Owner before the lineup is accepted, and shall obtain a signed receipt for them.
Spare Parts to Be Furnishedcheckbox
☑ One power cell or power module of each rating installed
☑ One set of input current-limiting fuses of each rating installed
☑ One set of control power fuses of each type and rating installed
☑ One cooling fan of each type installed
☑ One set of intake filter media for each lineup
☐ One control board or control module of each type installed
☐ One operator interface
☐ One network interface module
☐ One set of coolant, deionizer cartridges, and pump seals for a liquid-cooled lineup
☐ One set of indicating lamps and lenses of each type installed
☐ Touch-up finish in the exterior color
NOTE A spare power cell is the spare that turns a cell failure from a lead-time outage into a planned stop of an hour, and a cascaded drive with cell bypass runs on until that stop; a spare input fuse is what prevents a fuse of a different rating being installed to end an outage, which defeats the protection the transformer and the contactor depend on; a spare fan and a set of filter media are the parts that fail or foul first and are replaced without opening a medium-voltage door. (22.2)
22.3 Spare parts shall be of the same manufacturer and rating as the installed items, shall be delivered in their original packaging, and shall be labeled with the designation of the lineup and the section they serve, and a spare power cell shall be stored under the storage requirements of this standard and re-formed before use where the manufacturer's limit is exceeded.