Electric motor troubleshooting guide – Ashland 1200 TR User Manual

Page 39

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39

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.

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