The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 06, 1987
Filed:
Dec. 16, 1986
Itsuki Ban, Nerima-ku, Tokyo, JP;
Other;
Abstract
A m-phase semiconductor electric motor comprises an rotary transformer to excite a rotor; a shaft and a bearing for rotatably supporting the rotor; an exciting coil for exciting the rotor magnetic poles; the rotary transformer includes a first and a second soft-ferrite core having magnetic paths and arranged to rotate relative to each other, the first core is coupled to the rotor shaft, the second core is fixed to the motor housing, a primary and a secondary coil are mounted on the second and first cores, respectively; the motor further comprises an oscillator for supplying the primary coil with a high frequency current; an electric circuit for rectifying the output of the secondary coil to energize the exciting coil; a fixed armature having m-phase coils; position detecting means for generating rotor position signals, each of the rotor position signals having positive and negative portions alternating every 180 degrees electrical angle; means for providing a reference voltage for commanding output torque; a multiplier circuit for multiplying the position detecting signal; an armature current detecting circuit for detecting armature current; an armature current control circuit for controlling armature current such that the armature current is cut off to cause magnetic energy in the armature coil to flow back to D.C. source or to restore the armature current depending on the magnitude of the same.