| 摘要 |
PURPOSE:To detect a presence for electric conduction and a continuous operation for a long time, by means of providing a light emitting device at a period of the power source frquency during a time of conduction to the motor. CONSTITUTION:At a time of operation of the motor, a light emitting device 13 begins to operate a light emitting at a period of the power source frequency, with an output, routed through a light sensor 14, firstly releasing a reset signal of a discriminator 15, simultaneously becoming a clock signal input to a counter 16 to make the counting output value increasing. If an operation is stopped, a reset signal is outputted again from the discriminator 15, with an output of the counter 16 returning to zero, however, if the counter 16 continues a counting to a previously set value, a power source break directive signal is outputted from a comparator 17, that compares the output of the counter 16 and the set value, to operate a break device 18. In this way, a detection of conduction at the time of both left and right rotation of the motor can be operated by one detector, further by applying this detected signal, simultaneously with a decision made for a presence of conduction, also for a counting reference frequency signal input, a correctly protecting action will be operated for the motor. |
