| 摘要 |
PURPOSE:To improve safety in a motor lock preventor for air control door for a vehicular air conditioner, etc., in such a way that locking is discriminated by measuring load current, a motor is reversed with discriminating signals, and the original condition is recovered after the determined time. CONSTITUTION:When a motor 1 is in normal operation, since a load current detecting circuit 21 gives output V2 which is lower than the reference output V1, an arithmetic operational amplifier 17 is set to L level, output from a lock detecting circuit 16 in L level is applied as input to a motor rotational direction control circuit 13, control signals are transmitted as they are from exclusive OR circuits 14, 15 as output, so that rotational direction of a motor 1 can be controlled. When a door catches a foreign material, signals V2 from the load current detecting circuit 21 are turned out to be high than the reference signal V1, output from the lock detecting circuit 6 is set to H, the exclusive OR circuit 14, 15 are reversed, so that a timer 27 can be operated. In consequence, the motor 1 is reversed, and it recovers to the original condition after the lapse of time of the timer. Thus, locking can be prevented, and safety can be improved. |
