High performance high speed induction motors

High efficiency is a major influence in the design of modern motors, and together with both USA and European Directives´ legislating on efficiency, will become more so in the future. There are aspects over which customers have a major influence, and those over which manufacturers have a major influence. How these affect the efficiency depends upon the motor rating, duty and application. This paper explores some of those aspects and their effects, together with solutions developed by GEC ALSTHOM Large Machines Ltd. In particular a very effective solution for high speed motors is described which also solves many of the extra problems only applicable to variable speed drive motors