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...http://www.google.fr/patents/US4698563?utm_source=gb-gplus-shareBrevet US4698563 - Semiconductor electric motor having a rotary transformer to excite a rotor
Semiconductor electric motor having a rotary transformer to excite a rotor
