| 摘要 |
PURPOSE:To enable to accurately synchronously switch by detecting the phase coincidence when a multiplexed inverter power source and a commercial power source, sequentially setting the phases of the respective inverters at the prescribed interval, thereby synchronizing it. CONSTITUTION:A commercial power source 1 is connected through a contactor K2, and addition outputs of unit inverters 2-4 are connected through a contactor K1 to a motor 9. The signal of a frequency instruction unit 10 is formed to pulses of phases of +20 deg., 0 deg., -20 deg. corresponding to the respective inverters via a V/F converter 12, applied to input pulse selectors 13-15 together with pulses of the phases of +20 deg., 0 deg., -20 deg. of a synchronizing pulse generator 28 connected to the power source 1, the selectors 13-15 are sequentially set on the basis of the outputs of frequency coincidence and phase coincidence detectors 25, 26, thereby controlling the inverters 2-4. Accordingly, the synchronization is performed without phase mistake, thereby switching between the commercial power source and the inverter. |
