Corpus sync: neutrality remakes, note hygiene, datasheet relocation, transformer-split cross-refs
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title: Overhead Cranes and Hoists
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## Below-the-hook lifting devices, hooks, slings, and rigging hardware are governed by ASME B30.20 and B30.26; this standard ends at the hook block and does not specify lifting beams or rigging except to require that their weight be deducted from net usable capacity. {note}
−## Freestanding jib cranes and portable gantry cranes are closely related but sufficiently distinct that they are not fully specified here; where present they shall be coordinated as separate equipment. {note}
+## Freestanding jib cranes and portable gantry cranes are closely related but sufficiently distinct that they are not fully specified here; where present they shall be coordinated as separate equipment.
## The service or feeder conductors bringing power to the runway disconnecting means are part of the building power distribution and are governed by [[sync/distribution-feeder-cables]]; this standard begins at the runway disconnect. {note}
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−### Wheel-load and impact-force submittals shall be issued early enough that the runway beam designer can incorporate them before runway steel is released for fabrication. {note}
+### Wheel-load and impact-force submittals shall be issued early enough that the runway beam designer can incorporate them before runway steel is released for fabrication.
## Closeout Submittals {toc}
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−### Class C is the 80% case for process and general manufacturing facilities: moderate service, an average load near 50% of rated capacity, and up to roughly 10 lifts per hour. {note}
+### Class C covers most process and general manufacturing facilities: moderate service, an average load near 50% of rated capacity, and up to roughly 10 lifts per hour. {note}
### Foundries, container yards, and heavy fabrication bays shall be classified Class D; standby or maintenance-only hoists in equipment rooms may be classified Class A. {note}
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# Crane Configuration {toc}
−## The crane type shall be selected from rated capacity, span, and available headroom; top-running cranes maximize capacity and hook height, while underhung and workstation cranes trade capacity for low headroom, multiple-bay coverage, and easy track interlocking. {note}
+## The crane type shall be selected from rated capacity, span, and available headroom; top-running cranes maximize capacity and hook height, while underhung and workstation cranes trade capacity for low headroom, multiple-bay coverage, and easy track interlocking.
### The crane type shall be selected to suit the rated capacity, span, and headroom of the application.
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−### Lift height shall be the actual hook height required to reach the design pick points, not a rounded nominal value; specifying a round number instead of the true requirement is a frequent cause of a crane that cannot reach its pick points. {note}
+### Lift height shall be the actual hook height required to reach the design pick points, not a rounded nominal value; specifying a round number instead of the true requirement is a frequent cause of a crane that cannot reach its pick points.
# Hoist and Trolley {toc}
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−### Electric wire-rope hoists shall be used for capacities above 2 tons or for high-cycle service; electric chain hoists may be used for lighter, lower-cycle applications. {note}
+### Electric wire-rope hoists shall be used for capacities above 2 tons or for high-cycle service; electric chain hoists may be used for lighter, lower-cycle applications.
### The hoist trolley shall be of the motorized type matched to the runway or bridge beam flange, except where a hand-geared or push trolley is explicitly scheduled for a light workstation system.
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−### Variable frequency drive control is the 80% case for process cranes because it eliminates load swing on starting and stopping and reduces shock to the runway; VFDs shall be provided as crane-duty rated and coordinated for harmonic mitigation per [[sync/low-voltage-variable-frequency-drives]]. {note}
+### Variable frequency drive control is the usual choice for process cranes because it eliminates load swing on starting and stopping and reduces shock to the runway; VFDs shall be provided as crane-duty rated and coordinated for harmonic mitigation per [[sync/low-voltage-variable-frequency-drives]].
−### Specifying a VFD without confirming its crane-duty rating or harmonic mitigation causes nuisance trips; the drive selection and harmonic analysis are governed by [[sync/low-voltage-variable-frequency-drives]] and shall be coordinated with this standard. {note}
+### Specifying a VFD without confirming its crane-duty rating or harmonic mitigation causes nuisance trips; the drive selection and harmonic analysis are governed by [[sync/low-voltage-variable-frequency-drives]] and shall be coordinated with this standard.
```datasheet
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−### A hardwired pendant shall be provided as the primary or backup control unless a documented operating and safety program accepts radio-only control; radio-only control with no pendant backup is a single point of failure that most operator programs prohibit. {note}
+### A hardwired pendant shall be provided as the primary or backup control unless a documented operating and safety program accepts radio-only control; radio-only control with no pendant backup is a single point of failure that most operator programs prohibit.
### The pendant shall be strain-relieved independently of the control conductors and shall be suspended on a separate festoon or messenger from the trolley.
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# Structural Loads and Deflection {toc}
−## This section defines the crane loads the runway must resist and the deflection limits the crane requires; the loads are inputs handed to the runway beam designer under [[sync/structural-steel-framing]], and the deflection limits govern crane performance, not merely structural adequacy. {note}
+## This section defines the crane loads the runway must resist and the deflection limits the crane requires; the loads are inputs handed to the runway beam designer under [[sync/structural-steel-framing]], and the deflection limits govern crane performance, not merely structural adequacy.
### The crane manufacturer shall report the maximum vertical wheel load, lateral force, longitudinal force, and bumper impact force to the runway beam designer before runway steel is released.
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### A lateral crane load equal to 20% of the sum of the lifted load and trolley weight shall be applied at the top of the runway rail and distributed to the runway in accordance with ASCE 7-22 Section 4.10.2.
−### The runway beam vertical deflection under maximum wheel load shall not exceed L/600 of the runway span; this is a crane-performance limit and shall be coordinated with the runway beam designer, not assumed to be covered by structural adequacy alone. {note}
+### The runway beam vertical deflection under maximum wheel load shall not exceed L/600 of the runway span; this is a crane-performance limit and shall be coordinated with the runway beam designer, not assumed to be covered by structural adequacy alone.
### The bridge girder vertical deflection shall not exceed L/888 for CMAA Class A through C and L/1000 for Class D through F.
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## End stops and bumpers shall be installed at both ends of bridge and trolley travel before the crane is energized for testing.
−## Existing-runway upgrades shall verify that the existing runway beams, rail, and electrification are adequate for the new crane wheel loads and current draw before the new crane is placed in service; where the existing runway is inadequate, the deficiency shall be reported before installation proceeds. {note}
+## Existing-runway upgrades shall verify that the existing runway beams, rail, and electrification are adequate for the new crane wheel loads and current draw before the new crane is placed in service; where the existing runway is inadequate, the deficiency shall be reported before installation proceeds.
# Delivery, Storage, and Handling {toc}
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## The crane, hoist, drives, and controls shall be warranted against defects in materials and workmanship for the manufacturer's standard warranty period, not less than one year from substantial completion.
−## The warranty shall be void if the crane is operated above its rated capacity or outside its certified CMAA service class; the as-built service class and capacity shall be recorded in the closeout documents to establish the warranty basis. {note}
+## The warranty shall be void if the crane is operated above its rated capacity or outside its certified CMAA service class; the as-built service class and capacity shall be recorded in the closeout documents to establish the warranty basis.
# Spare Parts {toc}
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- Control contactors / VFD spare fuses
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