Self-starting synchronous motor with permanent magnet rotor

Claim 2

A multiphase heteropolar synchronous motor, comprising a permanent magnet rotor having a plurality of rotor poles, a stator surrounding the rotor and having a plurality of inwardly projecting stator poles, m phase windings on the poles, the poles forming a plurality of pairs p greater than two, the stator being formed of only a single stator body, the stator poles forming groups of three or more poles each with alternating north and south poles, the poles being grouped together at the interior of the stator circumference so that a mechanical offset angle in excess of 180/mp is formed between the pole groups for m phases and within each group the interpole distances of the stator being substantially equal or deviate only slightly from the interpole distances of the rotor, the rotor poles being permanently magnetized with peripherally alternate polarities.

Claim 3

A motor as in claim 1, characterized in that the angle exceeds 180/mp by a value less than 90/mp.

Claim 4

A motor as in claim 1 characterized in that with 2p rotor poles the stator includes 2p - m projecting stator poles.

Claim 5

A motor as in claim 2, characterized in that with 2p rotor poles the stator includes 2p- m projecting stator poles.

Claim 6

A motor as in claim 1, characterized in that with 2p rotor poles the number of inwardly projecting stator poles from the rotor equals one of 2p- m+1 and 2p- m+2.

Claim 7

A motor as in claim 1, characterized in that all windings on each stator pole are the same.

Claim 8

A motor as in claim 3, characterized in that all windings on each stator pole are the same.

Claim 9

A motor as in claim 3, characterized in that all windings on each stator pole are the same.

Claim 10

A motor as in claim 5, characterized in that all windings on each stator pole are the same.

Claim 11

A motor as in claim 1, characterized in that the stator windings in each pole group are equal to each other but only within the pole group.

Claim 12

A motor as in claim 2, characterized in that the stator windings in each pole group are equal to each other but only within the pole group.

Claim 13

A motor as in claim 4, characterized in that the stator windings in each pole group are equal to each other but only within the pole group.

Claim 14

A motor as in claim 5, characterized in that the stator windings in each pole group are equal to each other but only within the pole group.

Claim 15

A motor as in claim 1, wherein means energize the windings for operation as a stepping motor.

Claim 16

A multiphase heteropolar synchronous motor, comprising a permanent magnet rotor having a plurality of rotor poles, a stator surrounding the rotor and having a plurality of inwardly projecting stator poles, windings on the poles forming m phases, the poles forming a plurality of pairs p greater than 2, characterized in that the stator poles circumferentially form two groups of adjacent poles with alternating north and south poles within each group, the poles within each group on the stator having interpole distances substantially equal to or deviating only slightly from the interpole distances of the rotor poles, said rotor poles being permanently magnetized with peripherally alternating polarities, the circumferential distances between the groups of the poles being greater than the interpole distances between poles of each group, the groups of poles being offset from equiangular distribution about the periphery of the stator.

Claim 17

A multiphase heteropolar synchronous motor, comprising a permanent magnet rotor having a plurality of rotor poles, a stator surrounding the rotor and having a plurality of inwardly projecting stator poles, windings on the poles forming m phases, the poles forming a plurality of pairs p greater than 2, characterized in that the stator poles circumferentially form two groups of adjacent poles with alternating north and south poles within each group, the poles within each group on the stator having interpole distances substantially equal to or deviating only slightly from the interpole distances of the rotor poles, said rotor poles being permanently magnetized with peripherally alternating polarities, the circumferential distances between the groups of the poles being greater than the interpole distances between poles of each group, the groups of poles being offset from equiangular distribution about the periphery of the stator.

Claim 18

A motor as in claim 15 characterized in that the angular offset is less than 90/mp°.

Claim 19

A motor as in claim 1, wherein each of said stator poles has a cross-section at its end at least as small as throughout its length.

Claim 20

A motor as in claim 1, wherein said stator poles each has a substantially uniform cross-section throughout its length.

Claim 21

A motor as in claim 1, wherein said pole groups have an interpole distance of (a + 0.5) T p , wherein a is an integer greater than 0 and T p is the pole pitch within a group, said poles forming a two-phase motor.

Claim 22

A motor as in claim 1, wherein said groups of stator poles are separated from each other by a distance (a + 0.333) T p , wherein a is an integer greater than 0 and T p is the pole pitch within a group, said poles forming a three-phase motor.

Claim 23

An apparatus as in claim 19, wherein said stator poles each has a substantially uniform cross-section throughout its length.

Claim 24

An apparatus as in claim 20, wherein said stator poles each has a substantially uniform cross-section throughout its length.