Electric motor troubleshooting guide – Ashland 1200 TR User Manual
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ELECTRIC MOTOR TROUBLESHOOTING GUIDE
PROBLEM
POSSIBLE CAUSES
REMEDY
Overload Relays
Slow Starting (10- 15 seconds
Reduce starting load. Increase
Tripping Upon Starting
or more) due to High Inertia
motor size if necessary.
Load
Low voltage at motor
Improve power supply and/or
terminals.
increase line size.
Running Loaded
Overload.
Reduce load or increase motor
size
Unbalanced Input Current.
Balance supply voltage
Single Phasing
Eliminate
Excessive Voltage Drop
Eliminate (see above).
Too frequent starting or
Reduce frequency of starts
intermittent overloading.
and overloading or increase
motor size.
High Ambient Starter
Reduce ambient temperature
Temperatures
or provide outside source of
cooler air.
Wrong Size Relays
Correct size per nameplate
current of motor. Relays have
built in allowances for service
factor current. Refer to
National Electrical Code.
Excessive Vibration
Out of Balance:
(mechanical)
a. Motor mounting
Be sure motor mounting is
tight and solid.
b. Load.
Disconnect belt or coupling -
restart motor -if vibration
stops, the unbalance was in
load.
c. Sheaves or coupling
Remove sheave or coupling -
securely tape 1/2 key in shaft
keyway and restart motor -if
vibration stops, the unbalance
was in the sheave or coupling.
d. Motor
If the vibration does not stop
after checking a, band c
above, the unbalance is in the
motor -replace the motor.
e. Misalignment on Close
Check and realign motor to the
Coupled Application.
driven machine.