FAQs - LHP

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FAQs/Troubleshooting

Motor was running, Then Fails to Start
Replace the fuse or reset the breaker.
Stator is shorted or went to ground (Motor will make a humming noise and the circuit breaker or fuse will trip)
Check for leaks through the coils. If leaks are found, the motor must be replaced.
Motor overloaded or jammed
Inspect to see that the load is free. Verify the amp draw of motor versus the nameplate rating.
Capacitor (on single phase motor) may have failed

Load increased
Verify that the load has not changed and the equipment has not gotten tighter. If it is a fan application, verify that the air flow hasn’t changed.

Defective capacitor
Test the capacitor per previous instructions or check if some other equipment is taking power away from the motor.
Bad bearings
Noisy or rough feeling bearings should be replaced by the motor supplier. Voltage too low
Make sure the voltage is within 10% of the motor’s nameplate rating. If not, contact your power company

Verify that the motor is getting enough air for proper cooling.
Connect the motor terminals according to the connection diagram provided with the motor. 6. Motor
Overloaded/Thermal Protector Continuously Drips
Load too high
Verify that the load is not jammed. If the motor is a replacement, verify that the rating is the same as old motor.
Ambient temperature too high
Incorrect wiring / connection

Overload. Compare actual amps (measured) with nameplate rating
Locate and remove the source of excessive friction in the motor or load. Reduce the load or replace the motor with one of greater capacity.
Single phasing (three phase only)
Check the current at all phases. It should be approximately the same.
Improper ventilation
Check external cooling fan to be sure air is moving properly through the cooling channels. If there is excessive dirt build-up, clean the motor.
Unbalanced voltage (three phase only)
Check the voltage at all phases. It should be approximately the same.
Rotor rubbing on stator
Tighten the thru bolts.
Over voltage or under voltage
Check the input voltage at each phase of the motor to make sure the motor is running at voltage speciﬁed on the nameplate.
Open stator winding (three phase only)
Check the stator resistance at all three phases for balance.
Improper connections
Inspect all the electrical connections for proper termination, clearance, mechanical strength, and electrical continuity. Refer to the motor lead diagram.

Motor misaligned to load
Realign the load.
Load out of balance (direct drive application)
Remove the motor from load and inspect the motor by itself. Verify that the motor shaft is not bent.
Defective motor bearings
Test the motor by itself. If the bearings are bad, you will hear noises or feel roughness.
Load too light (single phase only)
Some vibration at a light load is standard. Consider switching to a smaller motor for excessive vibration.
Defective winding
Test the winding for shorted or open circuits. The amps may also be high. For defective winding, replace the motor.
High voltage
Check the power supply to make sure voltage is accurate.

Load to motor may be excessive or unbalanced
Check the motor load and inspect the drive belt tension to ensure it’s not too tight. An unbalanced load will also cause the bearings to fail.
High ambient temperatures
If the motor is used in an environment with high ambient temperatures, a different type of bearing grease may be required. You may need to consult the factory.
High motor temperatures
Check and compare the actual motor loads to the motor’s rated load capabilities.