| 摘要 |
Operating noise of a dynamo electric machine, and particularly a three-phase vehicular-type alternator, can be reduced by changing the reluctance or permeability of the magnetic path between rotor and stator of adjacent stator teeth by splitting the stator teeth to introduce additional radially extending gaps in the stator teeth or by distributing, non-uniformly or uniformly, ferromagnetic slot closers about the circumference of the stator slots while leaving, adjacent a stator slot with a magnetic closer, open stator slots or slots covered only with non-magnetic slot cover elements, such as treated paper, cardboard, or the like. This changes the frequency of attraction between rotor and stator to a frequency range which is not humanly perceptible or annoying, for example falling below the frequency range at which the alternator can operate, for example below idling speed of an internal combustion engine driving the alternator, or towards a frequency range so high that the operating noise level of the internal combustion engine masks any generator noise.
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