| 摘要 |
The separately-excited inverter circuit for performing the protecting operation upon the rise in the output voltage caused by the contact failure includes a switching circuit 26 b which applies the AC to a primary coil of a pressure-rising transformer 26 e, a control circuit C 1 which starts a switch control of the switching circuit 26 b upon an input of a command signal to set an oscillation state ON from a transmission line for the command signal to command to set the oscillation state ON and OFF, an output voltage monitor circuit 51 which allows a comparator 51 a to compare an output voltage of the separately-excited inverter circuit with a predetermined voltage, and to output a predetermined reference voltage when the output voltage is higher than the predetermined voltage, and a thyristor circuit 52 which is turned ON to set the transmission line of the command signal into an oscillation OFF state upon the input of the reference voltage to the gate to stop a switch control of the control circuit C 1 . The output voltage monitor circuit 51 outputs the reference voltage to make a time width sufficient to turn the thyristor circuit 52 ON using a hysteresis of the comparator 51 a. |
