| 摘要 |
PURPOSE:To avoid a mulfunction at the time of a testing an AC actuator drive circuit having the normal working by attaining confirmation for normal state of a bypass circuit. CONSTITUTION:In a positive half cycle of an AC power supply, a current flows in a route of an AC power supply 31, a triac 21a, a resistance 28 and the power supply 31. While the current flows in a route of the power supply 31, the resistance 28, the triac 21a and the power supply 31. Therefore it is possible to detect that IA+IR (IA: actuator current, IR: bypass resistance current) is changed to IR as long as the resistance value of the resistance 28 is set at a proper level in consideration of the current capacity of the triac 21a and the sensitivity of detection of a current pickup 26 and a deciding circuit 30. Then the open/ close state of a bypass contact 23, i.e., the normal state of a bypass circuit can be confirmed. |
