| 摘要 |
PURPOSE:To effectively detect a quenching operation (a transition to a normal conduction state) even when an alternating current, a direct current, an alternating current on which a direct current is superposed or a distorted wave is utilized by a method wherein the quenching operation is detected by a method for taking the difference between the integrated value of the coil voltage the coil current. CONSTITUTION:First, the terminal voltage of a coil is integrated. At this time, the voltage gain is adjusted by utilizing a voltage divider in the case of a direct current and by utilizing a voltage divider or a transformer in the case of an alternating current. On the other hand, as to the coil current a value proportional to the coil current in measured by a current detector inserted in series with the coil. The current detector is the same one used in the case of a DC current or an AC current transformer of the like in the case of an AC. The gain of the signal is also adjusted by an amplifier or an attenuator. Signals whose levels have been adjusted respectively are inputted into an error amplifier, and the difference between both is obtained. The difference voltage becomes an alternating current or a pulsating current including a DC component having positional information on the timing at which quenching has occurred. Consequently, the difference voltage can be utilized as monitoring information. |
