| 摘要 |
PURPOSE:To enhance the speed controlling accuracy by increasing the resistance of the secondary side resistor of an induction motor at the time of stalling or applying steady tension, thereby increasing the torque and preventing the stalling of the motor. CONSTITUTION:Contactors 54 are all shortcircuited in response to the signal of a controller 58 at the normal operation time, and a wound-rotor type induction motor 51 is controlled at the speed in response to the voltage and frequency applied from an inverter 38. When the slip obtained by calculation in the controller 58 exceeds an allowable value or when a steady tension is applied, the contactors 54 are switched by the output of the controller 58, thereby increasing the resistance value of the secondary side external resistor 52. |
