Low-power motors in PM line-start technique with surface-mounted magnets

Conference: IKMT 2015 - 10. ETG/GMM-Fachtagung Innovative Klein- und Mikroantriebstechnik
09/14/2015 - 09/15/2015 at Köln, Deutschland

Proceedings: ETG-Fb. 146: IKMT 2015

Pages: 7Language: englishTyp: PDF

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Schirmer, Hans-Georg; Huth, Gerhard (Institute for Mechatronic and Electrical Drive Systems, Department of Electrical and Computer Engineering, University of Kaiserslautern, Germany)

Due to the physics, line-start induction motors with small frame sizes cannot be realized in the energy efficiency class IE4. This product gap can be closed by PM line-start motors whose assembly is closely tied to squirrel cage induction motors of the energy efficiency class IE2. The squirrel cage is augmented by rare-earth magnets with a very high demagnetizing resistance on the rotor surface. Therefore, the rotor has to be turned down by the thickness of the banding and the magnets. This reduces the volume of the cage bars by about 20 – 30 %. For the frame sizes from 63 to 90mm, it will be demonstrated that a high efficiency and a robust pulling-in behavior are contrary development targets. If the squirrel cage is manufactured in copper die-cast, the PM line-start motors down to frame size 63 can reach the energy efficiency class IE4 in combination with a sufficient pulling-in behavior.