| 摘要 |
PURPOSE:To pull out yarn smoothly while preventing entanglement, loosening, cutting, etc., of yarn by driving a yarn feeder through an induction motor and controlling the induction motor in three modes of starting mode, continuous operation mode and D.C. brake mode. CONSTITUTION:When a weaving machine starts operation, yarn is pulled out intermittently from a yarn feed drum and consumed. When the quantity of yarn decreases below a predetermined level, a judging circuit 101 in control section 100 selects a starting circuit 104 based on a signal fed from a sensor 42 so as to increase source frequency gradually through a variable frequency generating circuit 105 thus starting rotation of an induction motor. When the yarn is wound by predetermined amount over the yarn feeding drum, a continuous operation circuit 103 is selected based on a signal fed from the sensor 42 so as to continue operation with steady operation and regenerative braking being repeated, and when the machine is stopped, D.C. brake is applied through a dynamic brake DB circuit 102. Consequently, the motor is rotated smoothly and the yarn is wound over the yarn feed drum by predetermined amount at all times thus enabling smooth pulling out of yarn without causing ballooning or snarl phenomenon.
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