DESIGN AND APPLICATION CONSIDERATIONS FOR MOTORS IN STEEP-FRONTED SURGE ENVIRONMENTS

A large body of research has been conducted in the past 15 years into steep-fronted surges in electrical systems and their propagation in ac machine windings. This paper will review the nature of the surge, the factors that determine its amplitude and rise time, and how it affect s the motor winding. It will then explain how its harmful effects can be controlled by system and winding design and by effective quality co ntrol, Related national and international standards will be discussed and their shortcomings pointed out. Uncertainties in the prediction of amplitude and rise time of surges will be explained, and guidance for cost effective specification of motors for application in a surge env ironment will be given.