Permanent magnets can only be operated in the linear portion of the demagnetization curve without being permanently demagnetized. Consequently, the magnets may only be stressed up to the limited field strength HG. Should the opposing field strength be larger than this, the operating point will travel across the bend of the B/H curve, and non-reversible demagnetization with a corresponding loss of flux will occur. The following four magnet materials will be considered: hard ferrites, AlNiCo materials, rare earth-cobalt magnets, and neodymium-iron-boron alloys. Their differing magnetic properties are shown in the demagnetization curves at room temperature. Electrical machines however, are operated at varying temperatures. For example, the temperature span for starter motors and alternators is -40 Cel to 150 Cel.
Application opportunities for permanent magnets in starter motors and alternators for passenger cars
Anwendungshinweise fuer Permanentmagneten in Anlassermotoren und Lichtmaschinen fuer PKWs
ICEM '86, International Conference on Electrical Machines ; 3 ; 1079-1082
1986
4 Seiten, 9 Bilder
Aufsatz (Konferenz)
Englisch
PERMANENTMAGNET , GLEICHSTROMMOTOR , ANLASSEN (MASCHINE) , KRAFTFAHRZEUGELEKTRIK , KRAFTFAHRZEUG , GENERATOR (ELEKTRISCHE MASCHINE) , ENTMAGNETISIERUNG , MAGNETISIERUNGSKENNLINIE , MAGNETLAEUFER , SELTENE ERDEN , FERRIT (SINTERWERKSTOFF) , KOSTENSENKUNG , GEWICHT , BUERSTE (SCHLEIFKONTAKT) , ERWAERMUNG , SPANNUNGSREGELUNG , GEWICHTSEINSPARUNG
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