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Multi-phase hybrid stepper motor

  • US 5,374,865 A
  • Filed: 07/30/1993
  • Issued: 12/20/1994
  • Est. Priority Date: 07/31/1992
  • Status: Expired due to Term
First Claim
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1. A multi-phase hybrid stepper motor comprising of a rotor system with at least one axially magnetized permanent magnet, having one polecap on each side;

  • the polecap made of soft magnetic iron having on its periphery a number of NR evenly spaced, radially outward directed teeth;

    the rotor polecaps on each side are offset in rotational direction to each other by one half (1/2) toothpitch Tp=360/NR, a nonsymmetrical stator surrounding the rotor and having ten (10) radially inwardly directed statorpoles, each of the statorpoles having one untapped winding;

    the statorpoles having two or more teeth spaces with the toothpitch Tp, a total number of stator teeth NS corresponding to the relation of NS=5(n0+n1) with n0 being number of teeth of each of 5 poles and n1 the number of teeth of each of remaining 5 poles, each one of the poles in between of the 5 poles with n0 teeth placed in such a way that opposite of each of the poles n0 teeth is one pole with n1, teeth, a relationship between the number of rotor teeth NR and the total number of the stator teeth NS of NS≧

    0.8 NR (equal or greater than) and with a difference between NR and NS which is defined by the equation NR-NS=K(S0-S1)+10(S1-1+B), where K is any integer varying from 2 to 5, S0 and S1 are integers as small as possible in such a way that S1 can also be equal to S0 and where B is a fraction of one (1) in such a way that 10B (10 times B) is always an integer; and

    a winding scheme in such a way that the 10 windings can be energized through a voltage source or current source so that said 10 windings form as many north-and south-poles necessary to achieve full stepangles=electrical angle 90=α

    F, α

    F=360 s/10 NR and half stepangle=electrical angle 45=α

    H, α

    H=360/20 NR.

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