| 摘要 |
PURPOSE:To prevent the lowering of the operating efficiency of a motor by changing the capacity of an operating capacitor on the basis of the output frequency of a power supply. CONSTITUTION:Operating capacitors 4, 5 are installed to displace the phase of the main winding 2 and auxiliary winding of a single-phase induction motor 1 at 90 deg.. A control section 12 controls the ON-OFF of switching elements 8, 9, 10, 11 so that the motor 1 is given the currents of frequency corresponding to a frequency signal transmitted to a terminal F. The control section 12 turns the contact 6 of a re-take ON-OFF through a transistor 13 with the frequency signal. Accordingly, the capacity of the capacitors connected to the auxiliary winding 3 is altered with frequency, and phase difference with the main winding is kept at a value close to 90 deg., thus improving efficiency. |
