Patent ID: 9653981
Date: 2017-05-16
CPC Classifications: H02K

Claim:
1. An electric motor, comprising: a stator having a plurality of phase windings forming a number of magnetic poles, wherein one of the phase windings wound on a bobbin is engaged with two pole plates; a rotor having a rotor core and a permanent magnet fixed to the rotor core; an output shaft, coupled to the rotor core; and a plurality of detent plates arranged to magnetically attract the rotor to the stator to hold the rotor in a desired rotational orientation with respect to the stator with a predetermined detent torque, the detent torque producing a corresponding torque variation, each of the plurality of detent plates comprising radially outer projections which engage a housing of the motor to hold each of the plurality of detent plates and to complete the magnetic connection therebetween; wherein the phase windings are asymmetric and produce different excited torques which when combined with the detent torque produce a combined output torque having a desired torque ripple.