Page 156 - Electrical Equipment Handbook _ Troubleshooting and Maintenance

MAINTENANCE OF MOTORS

MAINTENANCE OF MOTORS 8.11

PROBLEM D: Motor bearings run hot and noisy.
D1 Check loading. Is excessive side pressure, Yes Reduce overloading.*
end loading, or vibration overloading bearings? Install larger motor.
No
D2 Is sleeve bearing motor mounted on a slant Yes Mount horizontally* or
causing end thrust? install ball bearing motor.
No
D3 Is bent or misaligned shaft overloading Yes Replace bent shaft or align
bearings? shaft.*
No
D4 Is loose or damaged end bell overloading Yes Tighten or replace end bell.*
shaft?
No
Yes
D5 Are bearings dry? Lubricate.*
No
D6 Is bearing lubricant dirty, contaminated, or Yes Clean bearings and lubricate
of wrong grade? with proper grade.*
No
Yes
D7 Remove end bells. Are bearings misaligned, Replace.
worn, or damaged?
*BEARINGS MAY HAVE BEEN DAMAGED. IF MOTOR STILL RUNS NOISY OR HOT,
REPLACE BEARINGS.
FIGURE 8.2 (Continued) Troubleshooting ac motors.

dc
hipot Generator
supply winding

Neutral transformer
FIGURE 8.3 DC testing of a generator winding.

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