ELECTRIC MOTOR AND ELECTRICAL EQUIPMENT

PROBLEM TO BE SOLVED: To solve problems of an inverter-driven electric motor, in that a potential difference is caused between the outer ring and inner ring of a bearing, and a shaft current flows when an oil film in the bearing reaches a dielectric breakdown voltage, with the result that electric c...

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Bibliographic Details
Main Authors ISOMURA YOSHINORI, NAKANO KEISAKU, YOKOTE SHIZUKA
Format Patent
LanguageEnglish
Published 07.08.2014
Subjects
CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
DYNAMO-ELECTRIC MACHINES
ELECTRICITY
GENERATION
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Summary:PROBLEM TO BE SOLVED: To solve problems of an inverter-driven electric motor, in that a potential difference is caused between the outer ring and inner ring of a bearing, and a shaft current flows when an oil film in the bearing reaches a dielectric breakdown voltage, with the result that electric corrosion occurs in the bearing.SOLUTION: A mold motor comprises: a stator; a rotating body located opposite the stator and holding magnets in a circumferential direction thereof; a rotor including a shaft with the rotating body fastened thereto; a bearing supporting the shaft; two conductive brackets fixing the bearing; and a dielectric layer electrically connecting the two brackets and provided between the shaft and the periphery of the rotating body. In the mold motor, the shaft is provided at least one or more shaft current restriction devices formed from a magnetic body and a conductor.
Bibliography:Application Number: JP20130011633