Can a high efficiency MV motor be repaired?

High efficiency MV motors have been manufactured and installed for many years. These larger motors have been purchased as project specific and for the most part energy costs were considered in the purchase decision. The installed base of “High Efficiency MV motors” is thus large. With plants aging these motors eventually fail. With energy costs rising, customers are starting to question if, when these motors are repaired, their efficiency (and overall performance) can be maintained. This paper will specifically focus on the repair of MV motors, and shows through analyzing the specific losses in the motor if in fact motor can be repaired while maintaining original performance values. Real world examples are used to quantify possible changes in motor efficiency after different types of repairs.