Rockwell Automation 8720SM High Performance AC Induction Motors - Manual (Page 6)

Publication 8720SM-IN001A-EN-P — February 2003
6 8720SM High Performance AC Induction Motors
Using Belted Drives and Coupled Drives
Proper alignment is key for long life of bearings, shafts and belts, and
minimum downtime.
Belted Drives
If you use motor slide bases or rails, you must securely anchor them
to the foundation with the proper bolts. Make sure the motor shaft
and load shaft are parallel, and that the sheaves are aligned.
When a motor is belt coupled, the belt tension must not exceed the
radial load capabilities of the motor bearings. For belt drives, place the
sheave as close as possible to the motor bracket. The maximum
allowable radial load is assumed to be applied at the end of the motor
drive shaft.
Coupled Drives
Use flexible couplings between the motor shaft and the load shaft.
Align the motor shaft and the load shaft to values recommended for
the specific coupling before coupling is connected.
Balancing the Motor
Misalignment can cause excessive vibration and damaging forces to
the shaft and bearings. During high speed operation, a small
unbalance can cause significant vibration. Make sure to accurately
dynamically balance any gears, pulleys, or couplings that are mounted
to the motor shaft. Best results are obtained by balancing after the
device is mounted to the shaft.
Motors are dynamically balanced to stay within a vibration limit of
0.12 in./s, measured in accordance with NEMA MG-12.06. Balance is
done with a full length 1/2 height shaft key. A full shaft key is shipped
IMPORTANT
Do not exceed the maximum allowable radial load
on the end of the shaft. Refer to the Radial Load
Force Ratings (Zero Axial Load) on page 25 for a
listing of radial loads.
IMPORTANT
Do not exceed the maximum allowable axial load on
the end of the shaft. Refer to the Axial Load Force
Ratings (Zero Radial Load) on page 26 for a listing of
axial loads.