| 摘要 |
PURPOSE:To prevent breakage of a shaft of a motor, by a method wherein inverters of small capacity installed in parallel near a resonance point of an induction motor are operated simultaneously, and frequency of the inverters is varied. CONSTITUTION:A six-phase auxiliary inverter 8 having capacity of 10 % or less of full load state is installed in parallel to a six-phase main inverter 7. In the case of operation at resonance frequency range (20-40 Hz) of a motor and a load shaft, the six-phase auxiliary inverter 8 and the six-phase main inverter 7 are operated in parallel, and used as a 12-phase inverter. In this constitution, pulsating torque frequency and the resonance frequency are made not coincident with each other. |
