| 摘要 |
PURPOSE: To control tensile force at a constant force by taking measures which detect current of an alternating current motor, compare torque current component with torque command, and adjust forequency which is given to a waveform shaping circuit in a control circuit which controls an inverter circuit based on the results of the detection and comparison. CONSTITUTION: After ac power of an alternating current power supply 6 is converted into direct current in a converter circuit 7, it is again converted into alternating current in an inverter circuit 8 and supplied to a motor 4. For this reason, the motor 4 rotates and a winding roll 3 winds up a film 1. At this time, a pinch roller 2 rotates at a certain torque, and winding tensile force is determined by torque generated by the motor 4. When tensile force increases, primary current of the motor 4 increases. Primary current is detected by each current detector 101 to 103, phase current detected in a current detection circuit 11 is inputted to an energized component current/torque component current separation arithmetic circuit 12, and only torque component current is inputted to a comparison circuit 13. As a result, if a torque component current is large, a frequency reduction command is outputted. |
