Electric motor troubleshooting guide – Ashland 1200 TR User Manual

Page 38

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38

ELECTRIC MOTOR TROUBLESHOOTING GUIDE

PROBLEM

POSSIBLE CAUSES

REMEDY

Motor Runs Excessively Overloaded

Reduce load or load peaks

Hot

and number of starts in cycle

Blocked Ventilation:

Clean external ventilation

system - check fan.

a. TEFC's

Blowout internal ventilation

passages.

b. O.D.P.’s

Eliminate external interference to

motor ventilation.

High Ambient Temperature

Reduce ambient temperature

over 40°C (104°F).

or provide outside source of

cooler air.

Unbalanced Input Current.

Balance supply voltage.

Check motor leads for tightness

Single Phased

Eliminate single ph. condition.

Won't Start (just hums

Single Phases

Shut power off. Eliminate

and heats up)

single phasing. Check motor

leads for tightness.

Rotor or bearings locked.

Shut power off. Check shaft

for freeness of rotation.

Be sure proper sized overload

relays are in each of the 3

phases of starter. Refer to

National Electrical Code.

Runs Nolsv Under Load

Single Phases

Shut power off. If motor

(excessive electrical

cannot be restarted, it is single

noise or chatter under

phased. Eliminate single phasing.

load)

Be sure proper sized overload

relays are in each of the 3

phases of the starter. Refer to

National Electrical Code.

Excessive Voltage Drop Excessive Starting or Running

Reduce load.

(more than 2 or 3% of

Load

nominal supply voltage)

Inadequate Power Supply.

Consult power company.

Undersized Supply Lines.

Increase line sizes.

High Resistance Connections.

Check motor leads and

eliminate poor connections.

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