GB1273679A - Synchronous motor - Google Patents

Abstract

1,273,679. Electric motors. MATSUSHITA ELECTRIC WORKS Ltd. 28 April, 1970, No. 20357/70. Heading H2A. A self-starting synchronous motor comprises a stator and a rotor having an equal number of poles, either the stator or rotor poles being divided into two equal groups with the poles of one group of smaller width than those of the other group and offset from the position they would have adopted had the centre lines of all the stator poles been evenly spaced. The permanent magnet rotor, planar air gap motor disclosed has 32 rotor and stator poles, the latter being formed on a disc 6 of magnetic material. The disc 6 comprises inner and outer continuous rings 15, 16 joined by a first group of poles 17-32, Fig. 2, twice the width of a second group of poles 33-48. The broad and narrow poles are respectively joined to the outer and inner rings through narrow bridging pieces 17<SP>1</SP>-32<SP>1</SP> and 33<SP>1</SP>-48<SP>1</SP>. The narrow poles 33-48 are offset in the desired direction of rotor rotation by between one and three degrees. The broad and narrow poles assume opposite polarities when the coil 5 is energized. In a modification the magnet may be on the stator and the disc 6 on the rotor.