HVAC Variable Frequency Drives
Cross-references point to the standards that now own the topic after the October electrical rewrites: MV cable to medium-voltage-cables, energy storage to battery-energy-storage-systems, service grounding to grounding-and-bonding, lightning to lightning-protection.
Showing changes from Rev 6
to Rev 7
in HVAC Variable Frequency Drives.
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title: HVAC Variable Frequency Drives
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When to use: Separately procured pulse width modulated variable frequency drives rated 600 V and below, controlling three-phase AC induction motors on HVAC air and hydronic equipment — supply, return, and exhaust fans, chilled water, condenser water, and hot water pumps, and cooling tower fans. Covers drive ratings, enclosure and cooling selection, harmonic performance, bypass and disconnecting means, motor and cable compatibility, protective functions, building automation integration, testing, and installation for drives in mechanical rooms, electrical rooms, penthouses, and outdoor locations.
− Not intended for: Medium voltage drives above 600 V. Drives furnished as an integral factory component of packaged HVAC equipment such as chillers, packaged rooftop units, and factory-assembled air handling units, whose drive requirements belong to the equipment standard that governs the unit. Drives serving motors outside HVAC service, and drive-based motor control assembled into a motor control center (see [[sync/motor-control-centers]]). Soft starters, reduced-voltage starters, and across-the-line starters.
+ Not intended for: Medium voltage drives above 600 V ([[sync/medium-voltage-drives]]). Drives furnished as an integral factory component of packaged HVAC equipment such as chillers, packaged rooftop units, and factory-assembled air handling units, whose drive requirements belong to the equipment standard that governs the unit. Drives serving motors outside HVAC service, and drive-based motor control assembled into a motor control center (see [[sync/motor-control-centers]]). Soft starters, reduced-voltage starters, and across-the-line starters.
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## The following are outside this standard and are governed elsewhere. {note}
−- Drives rated above 600 V, which are medium voltage equipment with a different safety standard, enclosure practice, and switching topology
+- Drives rated above 600 V, which are medium voltage equipment with a different safety standard, enclosure practice, and switching topology ([[sync/medium-voltage-drives]])
- Drives built into factory-packaged HVAC equipment, where the packager owns the drive selection, its integration, and its warranty
- Drive sections assembled into a motor control center lineup, covered by [[sync/motor-control-centers]]
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### Arc flash warning labels shall be provided per NFPA 70E and the project arc flash study.
−### Label format shall follow the conventions in [[sync/low-voltage-switchgear]].
+### Label format shall follow the conventions in [[sync/equipment-labeling]].
# Delivery, Storage, and Handling {toc}
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### Cooling fans are the shortest-lived component in the drive and the most common cause of an overtemperature shutdown after a fouled intake. Both failures are correctable the same day when the replacement is already on site. {note}