Efficiency of Small Homopolar Synchronous Motors at High Speeds

Abstract

Summary In this paper, some efforts have been made to relate the efficiency of homopolar synchronous machines of the ‘reluctance rotor’ type to their design parameters. Particularly emphasized are the influences of the rotor pole shape, supply frequency and stator slotting. The indications given are based on results of numerous experiments on to prototype motors of a special design with a limited active length. From these results it is evident that only under exceptional circumstances, when despite high-speed operation excessive windage losses can be avoided, this kind of motor may be interesting for practical application.