| 摘要 |
PURPOSE:To enable to enhance the efficiency and to reduce the size of an inverter by normally supplying power from a power source directly to a load, and supplying power from an inverter to the load at the abnormal power source time. CONSTITUTION:When the fact that a commercial power source is normal is judged by a power level monitor 16, a firing command is applied to an AC switch 12 by the monitor 16 to close the switch, thereby supplying power directly from the power source to the load. When the malfunction of the power source is judged to be abnormal by the monitor 16, a gate signal of the switch 12 is blocked and opened, and switch circuits 26, 48 are opened. An inverter 14 is controlled in response to the set outputs of a frequency setter 32 and an output voltage setter 50, and power is response to the output of the inverter 14 is supplied to the load. |
