| 摘要 |
PURPOSE:To prevent the deterioration of the lifetime of a rope and also to prevent the break of the rope by outputting the torque value set previously in response to the gate position and controlling the torque of the driving force of a motor based on the torque value of the motor and the set torque value. CONSTITUTION:A pulse transmitter 6 generates the pulse signals in response to the revolution of a DC motor 2 which drives a rope mechanism 10 with revolution of a speed reducer 3 and opens/closes a gate 12. A shift value control circuit 7 counts the pulse signals to detect the position of the gate 12 and also selects a set torque against the position of the gate 12 to supply it to a stall torque control circuit 9. The circuit 9 compares the input current value supplied from a current detector 8 with the current value corresponding to the set torque supplied from the circuit 7 and produces a speed command signal needed to reduce the input current value less than the set torque current value. This command signal is supplied to a speed control circuit 5. Thus it is possible to prevent the excessive force applied to a rope, etc., and to evade the deterioration of the rope lifetime and the break of the rope. |
