ELECTRIC MOTOR HAVING ROTOR CAPABLE OF CONFINING MAGNETIC FLUX

摘要

An electric motor with high efficiency and excellent startability. The electric motor comprises a stator 20 having stator salient-poles 24 disposed annularly at regular intervals, and a rotor 10 having four permanent magnets 12a disposed at regular pitches, facing the inner circumferential sides of the stator salient-poles 24 and rotatably supported along the inner circumferences of the stator salient-poles 24. Magnetic flux from the permanent magnets 12a can be turned in the rotor 10 via a rotor ring Mp. An excitation control device 30 supplies the exciting current to excitation coils 24b of the stator salient-poles 24 in a predetermined order at predetermined timings depending on the excitation polarities, and the rotor 10 is driven in a synchronous manner. When the excitation coils 24b are in a non-excited state, the rotor 10 can rotate along the inner circumferential sides of the stator salient-poles 24 by confining the magnetic flux substantially without receiving any magnetic reluctance force, and its startability is excellent.