| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a relay failure detection device capable of reducing the case in which an open failure of a relay is detected although the relay does not have open failure. <P>SOLUTION: A microcomputer 30 detects a rear-stage voltage of a relay 31 by relay rear-stage voltage detection means Va. Further, a normally closed-side contact voltage of the relay 31 is detected by relay normally closed-side contact voltage detection means Vb. When a rear-stage voltage Vah of the relay 31 is equal to or lower than a threshold Vα, it is determined that relay contact abnormality has occurred. Then when relay contact abnormality determination means 30 determines that the relay contact abnormality has occurred, compares the rear-stage voltage Vah of the relay 31 with a normally closed-side contact voltage Vbh of the relay 31. When the rear-stage voltage Vah of the relay 31 is equal to the normally closed-side contact voltage Vbh of the relay, it is determined that normally closed-side contact abnormality has occurred. Then the microcomputer 30 turns on and off the relay 31 a plurality of times after a certain time has passed, and retries relay contact abnormality determination when it is determined that the normally closed-side contact abnormality has occurred. <P>COPYRIGHT: (C)2013,JPO&INPIT |
