Maintaining an induction motor consists mainly of observation and measurement; the aim is to catch a fault before it starts or grows. The catalogue's periodic maintenance recommendations are:

  • Cleanliness: keep the motor clean and dry; the fan cover and cooling fins must stay clear.
  • Terminal connections: check their tightness; a loose connection is a source of heat.
  • Bearings: monitor noise and vibration, and follow the greasing intervals.
  • Current: measure and record the motor current regularly; avoid overloading. A rising current trend at the same load is a warning of a fault.
  • Authorised work: leave winding and bearing work to an authorised service.

In addition, measuring frame temperature at the same spot and recording insulation resistance at least once a year makes trends easier to see. Maintenance frequency depends on how critical the motor is, the dust and humidity of the environment and running hours. For a sample schedule, see motor periodic maintenance schedule, and for early failure causes, motor lifespan and early failures.