| 摘要 |
PURPOSE:To suppress the thermal load of a motor by providing a calculation controller for generating a speed control reference value and a current limit selection value in response to the state of acceleration, deceleration and load of the motor. CONSTITUTION:A calculation controller 12 notifies the position of a truck 1 by a mechanical position detector 13. When an operation sequence moves a truck 1 from a standby position A to a loading position B, it selects and applies current limit value 140% at no load time to a current limit value selector 9, and applies a running speed reference to a speed control unit 10. When the truck 1 stops at the position B and loads the heavy load 3, the current limit value is selected to 280%, and the truck 1 is moved to the unloading position C. When unloading the load 3 and returned from the position C to the position A, the current limit value is selected to 140%. In this manner, necessary torque characteristic and thermal load characteristic can be utilized in good balance. |
