Craig & Antonelli
Electric motor having frequency generator
 An electric motor having a rotor consisting of a disk-shaped multi-polar magnet circumferentially sectioned to have a plurality of magnetic poles, a stator consisting of a pair of superimposed star-shaped flat driving coils, said driving coils being disposed facing said magnet, said driving coils being arranged to be supplied with respective alternating currents having a phase differential of 90.degree. thereby to drive the disk-shaped magnet, said motor further comprising a speed detecting coil having a plurality of radially disposed generating wire elements, said generating wire elements being disposed within a magnetic field of said magnet and being connected in series, whereby a signal having a frequency corresponding to the revolution speed of said disk-shaped magnet is induced in said speed detecting coil. 
Hitachi, Ltd. Japan Servo Co., Ltd.
H G
H02K G01P
inventional inventional
Hiroshi Masahiko Toshihiko
Hagino Fujita Gotoh