Rockwell Automation 7000A PowerFlex Medium Voltage AC Drive (A Frame) - ForGe Control - Manual (Page 110)

110 Rockwell Automation Publication 7000A-UM200C-EN-P - June 2014
Chapter 3 Component Definition and Maintenance
Fan Balance
Fan impellers are statically and dynamically balanced within acceptable
tolerances at the factory. Damage in shipping or from poor handling or
installation may upset the unit’s balance. An impeller that is not properly
balanced can lead to excessive vibration causing undue wear on the entire unit.
If vibration is excessive, shut down the fan and determine the cause.
Common causes of excessive vibration
• Support structure not sufficiently rigid or level.
• Vibration amplified by resonance in duct work or support structure.
• Bearing locking collar or mounting bolts loose.
• Loose impeller or bushing.
• Material accumulation on impeller.
• Wheel rubbing on inlet ring.
Impeller Maintenance Isolation Transformer Cooling Fan
The isolation transformer fan motor and impeller is an integral unit and cannot
be serviced separately.
Inlet Ring Removal and
Replacement The inlet ring is the large circular part located beneath the fan impeller.
It is positioned such that the impeller sits outside but does not touch the ring.
The ring sits inside the impeller 10 mm (0.40 in.). Refer to the cutaway view of
fan impeller and bushing (
Figure 89 ).
This procedure will require coming in contact with the internal electrical
connectors and devices.
Precautions must be taken to prevent the inlet ring from falling after all of the
bolts have been removed.
WARNING: All power MUST be removed from the drive. Failing to do so may
result in serious injury or death.
ATTENTION: To prevent electrical shock, ensure the main power has been
disconnected before working within the DC Link and Fan Area. Verify all circuits
are voltage free using a hot stick or appropriate high voltage-measuring device.
Failure to do so may result in injury or death.