| 摘要 |
PURPOSE:To semipermanently provide the lifetime of an induction motor by controlling the motor with a thyristor controller, and controlling the thyristor with a circuit with includes a counter and a D/A converter. CONSTITUTION:When an induction motor which drives a scraper or the like for a needle making machine is controlled by a thyristor controller, a control circuit is formed of a pulse generator 1, counters 2, 4 and a D/A converter 6. The initial voltage value is outputted from the counter 4 by an operation start signal, then a signal is inputted to the ounter 4 from the counter 2 at every t seconds to counter down the counter 2 by the divided minimum voltage to finally reach 0V, and a thyristor controller is controlled through the converter 6. Accordingly, the motor speed is uniformalized in variation in the speed and is gradually lowered, and the lifetime of the motor can be increased without maintenance. |
