9
TROUBLESHOOTING CHART
Table C –Suggested Regreasing Intervals
NOTE 1: Motors operating faster than 1800 RPM should be relubricated on a more frequent maintenance schedule. Use a reputablebrand
lithium or synthetic-base grease intended for electric motor ball bearings. Recommended greases include: Standard Oil of California
(Chevron) SRI#2, and Exxon Corp. PolyRex-EM. Keep grease container clean and covered.
-------------Motor HP at 1800 RPM Max.--------------
Type of service Under 50 50 to 100 Over 100
Infrequent operation or light duty in clean atmosphere 2 Years 2 Years 1 Year
8 to 16 hours per day in clean, relatively dry atmosphere 2 Years 1 ½ Years 1 Year
12 to 24 hours per day heavy duty use, or if moisture is present 1 Year 1 Year 6 months
Heavy duty use in dirty, dusty locations; high ambients; moisture
laden atmosphere; constant vibration
4 months 4 months 3 months
This chart suggests common answers to electric motor problems. The information is not all-inclusive and does not necessarily
apply in all cases. When unusual operating conditions, repetitive failures, or other problems occur, consult an electric motor
service firm for assistance.
Symptom Possible Cause(s) Corrective Action
Motor fails to start 1. Blown fuses
2.Voltage too low at motor terminals
due to line drop
3.Overload in motor starter tripped
4.Overload (internal thermal protec-
tor) tripped
5.Improper line connections
6.Motor may be overloaded
7. Defective motor or starter.
1. Replace with time-delay fuses. Check for grounded winding
2. Consult local power company. Increase wire size (refer to
Tables A & B). Check for poor connections
3. Check and reset overload relay in starter. Check heater rat-
ing against motor nameplate current rating
4. Check motor load. If motor has an automatic or manual reset
thermal protector, check if tripped
5. Check connections against diagram supplied with motor
6. Reduce load or increase motor size
7. Repair or replace
Motor does not come up to
speed or takes too long to
accelerate
1. Not applied properly.
2. Voltage too low at motor terminals
3. Starting load too high.
4. Excess loading; tight belts
5. Defective motor
6. Inadequate starting torque. High
inertia load
1. Consult motor service firm for proper type. Use larger motor.
2. Increase wire size (refer to Tables A & B). Check for poor
connections. Check for voltage unbalance (3-Phase)
3. Check load motor is carrying at start.
4. Reduce load; adjust belts. Increase motor size.
5. Repair or replace
6. Replace with larger motor
Motor stalls during opera-
tion
1. Overloaded motor
2. Low motor voltage
1. Reduce load or increase motor size
2. Verify that nameplate voltage is maintained
