Direct-on-Line Synchronous Reluctance Motor Loss Segregation with Measurements

Abstract

Although the share of variable speed motor systems is increasing, direct-on-line (DOL) motors still have their place in the market. Induction motor (IM) has been the undisputed DOL leader, but efficiency-wise better alternatives - such as DOL synchronous reluctance motors (SynRM) and DOL permanent magnet synchronous motors (PMSM) - are available. For DOL IMs, international efficiency standards provide a loss segregation procedure as a low uncertainty loss and efficiency determination method. In this paper, the IEC loss segregation method is applied to two DOL SynRM prototypes and the results are compared with direct input-output measurement results and with results from an IM counterpart. The results show that the induction motor loss segregation method is applicable also to DOL SynRMs and it can be used to examine the loss components of the machine.