Overview of Retrofitting Options in Induction Motors to Improve Their Efficiency and Reliability

The global induction motor market is moving fast towards the higher efficiency classes, such as premium efficiency (IE3) and super-premium efficiency (IE4) classes. Despite that, the existing operating motor stock is still dominated by below-standard and standard motors, since, on average, induction motors, regardless their efficiency classes, can be repaired/rewound 2–4 times over their useful lifetime of 12–20 years. Hence, it is important that the repair/rewinding practices are of the highest quality possible, to ensure that the motor efficiency and reliability are maintained during that process, particularly in the case of motors of higher efficiency classes. In many cases, the motor efficiency and reliability can even be improved during the repair/rewinding process. In this paper, an overview of retrofitting options in induction motors to improve their efficiency and reliability is presented, and an international accreditation program for electric motor repair centers/shops is briefly described.