Patent ID: 6476534
Filing Date: 2002-11-05
Classification: H02K,Y02E

Abstract:
An electromagnetic actuator with a rotor portion having an axis and a perimeter and having a stator portion, said rotor portion rotating substantially at the same speed as a rotating shaft, for actuating control of an instrumentality rotated with said shaft by one of a relative position, juxtaposition, or phasing relationship between said rotor and said shaft, said electromagnetic activator comprising:a plurality of permanently-magnetized regions located proximate the perimeter of said rotor portion, said permanently magnetized regions being polarized so that adjacent permanently magnetized regions about the perimeter of the rotor are of opposite magnetic polarity; a plurality of electromagnets each having a core and a coil surrounding the core mounted on the stator and positioned proximate the permanently magnetized regions, said electromagnets being subject to energization so that adjacent poles of said cores are of opposite magnetic polarity; the energization of the electromagnets causing a reversal of polarity at a frequency proportional to the rotational speed of the rotor, such that the cores reverse polarity each time that a permanently magnetized region on the rotor advances from being proximate one core to being proximate the adjacent core; the phasing of the reversals of the energizing polarity of the electromagnets being variable with respect to the rotation of the shaft so as to control the phasing of the instantaneous rotational position of the rotor with respect to the shaft; and a linkage means for extracting a relative-position signal from the juxtaposition of said rotating shaft and said rotor portion for affecting said instrumentality.