| 摘要 |
PROBLEM TO BE SOLVED: To enable arm short-circuit detection without a current detecting equipment, by comparing the changing timing of an output signal and the changing timing of a gate control signal waveform which are obtained by comparison of a voltage monitoring equipment, by using a voltage comparater. SOLUTION: A voltage monitoring equipment 9 compares a voltage of a voltage dividing point of a voltage dividing resistor 5 between P and N of P side conductor 3 and N side conductor 4, and a voltage of a voltage dividing point of an output voltage dividing resistor 8 inserted between an output terminal 11 and N side conductor 4. The voltage between P and N is compared with an output voltage 22 by using the voltage monitoring equipment 9, and an output signal 23 is formed by the comparison. In a voltage comparater 10, the output signal 23 by comparison is compared with a gate control signal waveform 21 of a switching element 6. When the time difference of ON and OFF exceeds allowable time, it is judged that operation in accordance with an output command is not performed and arm short-circuit is generated, and an alarm is outputted. |
