Three Phase Induction Motor Overheating: Common Causes of Bearing and Winding Failure

Bearing failure, overload, insulation breakdown, environmental contamination, improper input power, can all be reasons for early failure. If the motor has gotten to a certain heat the insulation in the stator windings will be irreparably damaged. Continued use can result in catastrophic failure. In that case the motor should be replaced. When replacing the motor be sure it has proper power available to drive it, that is sufficient size for the intended load and that it has sufficient cooling airflow.

Thank you very much for your reply.

Check the current of all three phase input with Clamp Meter .It should be equal.
If any one of three phase winding of motor is short or have poor insulation then motor will be over heated.

Overheating Electric Motors: One Root Cause of Insulation
Failure
Bearing and winding failures are the most common motor failures. The fundamental reason is excessive
heat. Today’s preventive maintenance practices frequently limit on-line electrical measurements to
interpret current levels. While tremendously important, this method is inconclusive in many of the
failures caused by excessive winding heat. The best way to ensure successful preventive maintenance
and monitoring is to test according to NEMA and other professional standards. Effective service factor
has been found to be a good measurement allowing difficult standards to be interpreted for day-to-day
plant operation. Even though instrumentation has not been available to monitor the frequency of starts
and stops, it is an important point in motor integrity. Automated assessment is necessary to effectively
ensure motor health.
The more successful root cause analysis of motor failure or stress, the more suitable predictive
maintenance becomes for plant management. This point represents good news for business; since
electrical on-line monitoring technology has successfully become an equal partner with vibration in
ensuring plant operation and up time.

Thank you for your reply Sir, I will carry out this observation and let u know.

You might also want to check your power leads. Make sure they are tight. Sometimes one of the power leads might loosen up as they heat (current draw). Then the motor would single phase. This is where the motor starts out normally then loses a phase. It will continue to run until the overloads pop. If the overloads are set to high then the motor would overheat and eventually pop the overload or burn up. Remember that the overloads are a timed function of the amount of overload.

You can also check if the cooling fan is proper conected. It is not the first time that i see the fixing screw missing.

Bearing and winding failures are the most common motor failures. The fundamental reason is excessive heat.