| 摘要 |
PURPOSE:To protect a power source by opening a breaker at the output side of an inverter in response to the defect of the output DC voltage of a chopper and the defect of the AC output voltage of the inverter, thereby early detecting the defects. CONSTITUTION:When a defect occurs in a constant voltage controller 6 or a chopper 1, a DC voltage detector 9 detects it. On the other hand, the output defect of the chopper 1 also affects the output of an inverter 3, but since a reactor is provided at the input side of the inverter 3, the output defect of the chopper 1 is delayed in time to present as the output defect of the inverter 3. Accordingly, when the defect occurs at the output of the chopper 1, a breaker operating circuit 8 opens a breaker 4 in response to the output of a DC voltage detector 9. The circuit 8 discriminates the generating timing of the output signals of the circuit 9 and an AC voltage detector 7, thereby identifying whether the cause exists at the input side or output side of the inverter 3. |
