| 摘要 |
PURPOSE:To prevent collision against environmental devices due to the disconnec tion of a speed control signal wire by a method wherein a speed detecting means is deemed to be abnormal and a DC motor is stopped when a speed detecting signal is zero and a voltage commanding value has exceeded a voltage drop. CONSTITUTION:The title device is provided with a current detecting means 9, detecting a current I supplied to an armature, a voltage drop operating means 11, operating and outputting a voltage drop generated in the resistor R of the armature or a commanding voltage operating value V1* utilizing the values of the resistor R and the current I based on the current I of the armature, a means to deem a speed detecting means 4 abnormal when a speed detecting signal is zero and a voltage commanding value has exceeded a voltage drop and stop a DC motor by providing a pulse generating circuit 8 with a pulse intercepting signal 16, or a trouble diagnostic circuit 12 and the like. According to this method, the motor may be stopped with a small amount of rotation, whereby collision against environmental devices due to the disconnection of a speed signal wire may be reduced as much as possible. |
