| 摘要 |
PURPOSE:To prevent the damage on a surge absorber for an apparatus on the load side by a method wherein, when a reversed phase is detected, an alarm is displayed on a display device, an inverter is stopped, a changeover device is controlled and a single-phase commercial power supply is sent directly to the apparatus on the load side. CONSTITUTION:When outputs from ends, on one side, of capacitors 5, 6 for a rectifyling circuit 2 which rectifies a single-phase commercial power supply to a double voltage and from a case ground E are input, whether a ground is a positive-phase ground or a reversed-phase ground is judged by a reversed- phase detection time control circuit 17. When the judged ground is the positive- phase ground, the output of an inverter 7 is input to an apparatus on the load side. When the judged ground is the reversed-phase ground, the inverter 7 is stopped, changeover devices 8 to 11 are controlled, the single-phase commercial power supply is sent directly to the apparatus on the load side, and an alarm is displayed on a display device. Thereby, it is possible to prevent the damage on a surge absorber for the apparatus on the load side. |
