User Manual

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.