12
Symptom
Possible Cause(s)
Corrective Action
5. Defective motor.
5. Replace or repair
6. Inadequate starting torque. High
inertia load
6. Replace with a larger motor
Motor stalls during
operation
1. Overloaded motor
1. Reduce load or increase the
motor size
2. Low motor voltage
2. Verify that nameplate voltage is
maintained
Motor vibrates or is
excessively noisy
1. Motor shaft is misaligned
1. Realign
2. 3-phase motor running on single
phase
2. Check for open circuit, blown
fuses or unbalanced voltages
3. High or unbalanced voltages
3. Check wiring connections.
Consult local power company
4. Worn, damaged, dirty or
overloaded bearings
4. Replace bearings; check
loading and alignment
5. Defective winding. Bent or
bowed shaft
5. Repair or replace
6. Loose sheave or misaligned
coupling
6. Tighten set screw(s); realign
coupling
Motor overheats while
running under load
1. Overloaded
1. Reduce load; increase motor
size; belts may be too tight
2. Dirt blocking ventilation openings 2. Clean motor
3. If 3-Phase, one phase may be
open
3. Check lines for open phase.
Check voltage with motor
disconnected, one fuse may be
blown.
4. Unbalanced supply voltage
4. Check for faulty connections.
Voltage on all three lines
should be balanced within 1%.
Balance single phase loads.
5. Faulty connection
5. Clean, tighten, or replace
6. High or low voltage
6. Check voltage at motor, should
not be more than 10% above or
below rated
7. Defective motor
7. Repair or replace
