Motor Fails to Start

  • Check connections, Motor is wired correctly?
  • Refer to the connection diagram to verify the motor is wired correctly.
  • Is Motor damaged and rotor is touching stator
  • Rotate the motor’s shaft and feel for rubbing
  • Power supply or line issue
  • Check the source of power, overload, fuses, controls, etc.

Motor was running, Then Fails to Start

  • 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

Motor Runs but Down suddenly

  • 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.

Motor Takes Too Long to Accelerate

  • 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

Motor Runs in the Wrong Direction

  • 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

Motor Overheating

  • 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 Vibrates

  • 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.

Bearings Fail

  • 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.