Rockwell Automation 7000 PowerFlex Medium Voltage AC Drive (B Frame) - Classic Control - Manual (Page 350)

6-60 Component Definition and Maintenance
7000-UM150I-EN-P – June 2013 7000 “B” Frame
To Assemble:
1. Make sure the shaft and keyway are clean and smooth. Clean
the shaft and bore with rubbing alcohol or non oily solvent.
Check the key size with both the shaft and bushing keyways.
2. Put the capscrews through the clearance holes in the bushing and
put the bushing loosely into the impeller, lining up the screws
with the threaded holes on the impeller hub. Do not press, drive
or hammer the bushing into the bore.
3. Start the capscrews by hand, turning them just enough to engage
the threads. Do not use a wrench at this time. The bushing
should be loose enough in the impeller to move freely.
4. Slide the impeller and bushing assembly onto the motor shaft,
ensuring the same distance from the end of the shaft to the
bushing as in step 1 of impeller removal.
5. Fit the key into keyway. Do not force impeller and bushing onto
shaft. If they do not fit easily, check the shaft, bushing and key
sizes.
6. Tighten the capscrews progressively with a wrench. Do this
evenly as though mounting an automobile wheel. Turn one a
quarter turn, then the next a quarter turn, then go back and turn the
other a quarter turn and so on. Torque to 10.2 N-m (7.5 ft-lbs.)
7. Peen the end of the motor shaft at the keyway with a chisel or
center punch to prevent the key from falling out of position.
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. Impeller or
bushing loose.
 Material accumulation on impeller.
 Wheel rubbing on inlet ring.