| 摘要 |
PURPOSE:To prevent the torque of a pole change type induction motor at the time of operating it at a low speed by applying magnetic anisotropy to its rotor to provide salient polarity of the number of poles having the same as or double of that of the number of armature windings at a low speed side. CONSTITUTION:Salient poles 7 are formed at equal intervals on the outer periphery of a rotor 4. Magnetic anisotropy is applied to the rotor 4 by the poles 7, and the number of poles is the same as that of the poles of armature windings 3b of armature windings 3 at a low speed side. Then, when windings 3a at a high speed side are made conductive, a revolving magnetic field is formed, and an induction torque is generated between them and squirrel-cage conductors 6 to cause the rotor 4 to rotate. When the windings 3b are made conductive, a large reluctance torque is generated near a synchronizing speed since the windings 3b have the same number as that of the salient poles 7 of the rotor 4, and the rotor 4 is eventually rotated at the synchronizing speed. Thus, since it is operated as an induction motor at high speed and as a reluctance motor at low speed, it can prevent the torque from decreasing at the time of low-speed operation.
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