Rockwell Automation 7000 PowerFlex Medium Voltage AC Drive (B Frame) - ForGe Control (PanelView 550) - Manual (Page 98)

98 Rockwell Automation Publication 7000-UM151E-EN-P - January 2013
Chapter 3 Component Definition and Maintenance
Installing Impeller Assembly onto Motor Shaft
The bushing barrel and the bore of the impeller are tapered which assures
concentric mounting and keeps the impeller running evenly.
The cap screws, when tightened, lock the bushing in the impeller and over the
motor shaft.
The bushing is split down the middle, so that when the locking cap screws force
the bushing into the tapered bore in the impeller assembly, the bushing will grip
the shaft with a positive clamping fit.
The impeller and bushing assembly have keyways that line up with the shaft and
are held in place with compression.
To assemble:
1. Ensure 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 cap screws 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 cap screws 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 cap screws 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.