| 摘要 |
PROBLEM TO BE SOLVED: To improve the detectability of relay abnormal decision at the rotation of a motor, when deciding the abnormality of a relay for intercepting the output of the motor.SOLUTION: When abnormality of relays 21a, 21b is performed by motor terminal voltage monitoring means 22, 23, a plurality of switching elements 20a to 20d are switched on to perform dynamic braking, and thereafter, to decide the abnormality of the relay 21a, there is used the motor terminal voltage monitoring means 22 when the switching element 20c is switched on. Also, to decide the abnormality of the relay 21b, there is used the motor terminal voltage monitoring means 23 when the switching element 20d is switched on. |
