| 摘要 |
PURPOSE:To enable proper inspection of the operation of a relay contact and a wiring system by installing a power source capable of passing a reverse current through the relay contact and a load and installing a reverse current detector. CONSTITUTION:A relay 6 to be inspected drives an externally fixed coil 5 through the contact 8 thereof. A changeover switch 1a, a current detection circuit 2, a power source 3, and a diode 4 are installed for inspection of operation. The power source 3 generates an inspection current 13 flowing in the opposite direction to that of an ordinary current. In inspection, the changeover switch 1a is changed over to the inspection side and the relay 6 is turned on through a transistor 7 by the command of an inspection part 11. When the wiring including the contact 8 of the relay 6 is normal, the inspection current 13 of the power source 3 flows to the current detection circuit 2 via the diode 4. In this time, the externally fixed coil 5 bypassed by the diode 4 is not operated. Thereby the operation of the relay can be inspected by detecting the inspection current 13 with a photocoupler 2c. |
