| 摘要 |
PURPOSE:To conduct low-speed variable-speed operation, in which pulsating torque is inhibited, by changing power frequency in the operation region of higher-harmonic synchronous torque. CONSTITUTION:In a squirrel cage type induction motor, higher-harmonic synchronous torque is generated in a specific slip S=1-P/Z2 when there is the relationship of Z2=Z1+P among rotor-groove number Z2, stator-groove number Z1 and pole number P. When stator-groove number Z1 is 36 and rotor-groove number Z2 is 40 in the squirrel cage type induction motor having four poles, large synchronous torque is generated in the slip of S=1-4/40=0.9. the number of revolution NSY at that time is NSY=120/Z2.f-that is, 150rpm, when frequency f is 50Hz, and reaches one tenth of synchronous speed. That is, variable frequency operation is conducted under the state of operation only when the induction motor is not worked as a normal one and high-harmonic synchronous torque is generated. |
