| 摘要 |
PURPOSE:To enable to guarantee the motor protecting range equivalent to the temperature rise coefficient of a motor by detecting the abnormal input of the motor at the starting time in the operating time avoiding the in-rush production time. CONSTITUTION:When an in-rush current is generated at the time of starting a motor, a comparator 4 generates an operation signal, and a constant-voltage holding circuit 22 holds the output of the comparator 4. Integrating circuits 8, 23 are charged by the output of the circuit 22. When the prescribed operating time is elapsed, a comparator 9 generates an output signal, and when the comparator 4 generates an output signal due to the delay of start at this time, a relay 11 will operate. When the time is further elapsed, a comparator 24 generates a lock signal, thereby continuously locking the motor start protecting circuit. When the motor is stopped, a constant-voltage holding circuit 21 is released by the output of the comparator 20. |
