Considerations for repair or replacement of AC motors

The decision to repair or replace a given AC induction motor needs to be done before the motor fails. Waiting until the time of failure usually results in hurried financial decisions for the business but, pre-planning will save many dollars and eliminate a lot of stress. A part of pre-planning is predictive maintenance. A program of periodic measurements of megger readings, polarization index values and vibration analysis can forewarn of an impending failure. This will permit the change or repair a given motor before it shuts the production down. The author describes how there are many factors that must enter into the decision to repair or replace an electric motor. Downtime, in most cases, is the greatest cost; relative cost, size, availability and expected life are the other major considerations for this decision