| 摘要 |
1280046 Electric motors core constructions MALLORY TIMERS Ltd 3 Nov 1969 [13 Nov 1968] 53736/69 Heading H2A A synchronous motor includes a wrong direction inhibiting device comprising a member, e.g. cam 35, Fig. 5 mounted on the motor rotor and a stop, e.g. pawl 40, the arrangement being such that when the rotor is stopped after rotating in the wrong direction at least one of its poles overlaps a stator pole by about half of its width, in order to create unbalanced magnetic forces and facilitate starting in the right direction. To further assist starting, the stator poles, which are stamped out of housing half shells 10, 11 are non-uniformly circumferentially spaced and every third pole is half the width of the other poles. The rotor comprises either a disc-shaped permanent magnet with alternate N and S poles round its periphery or an axially magnetized disc magnet located between two ferromagnetic plates 19, 20, Fig. 4, having interdigitated teeth. The pawl is resilient and may have only one stop face or two, as shown at 44 and 45. The rotor drives a gear train 50 mounted in a casing 14 secured to the motor housing by studs 48 formed integrally with the bobbin 16<SP>1</SP> carrying the stator winding. The bobbin is made of thermoplastic material or thermosetting resin or plastic. Grooves 33, Fig. 2, (not shown), on the innner periphery of the bobbin facilitate proper alignment of the stator poles. The bobbin is located in the housing by integrally formed bosses 54. |
