| 摘要 |
PURPOSE:To suppress the overshoot of the speed of revolution of a motor at the minimum value by mounting a switching element in parallel with the coil for exciting the electromagnetic clutch and controlling flywheel currents flowing through the coil. CONSTITUTION:A thyristor 96 is connected in parallel with the clutch coil 18, and a circuit outputting thyristor-OFF signals SG11a for controlling the thyristor 96 and thyristor-ON signals SG19 is mounted. Flywheel currents flowing through the clutch coil 18 in case of the conduction and interruption of the clutch coil 18 are controlled in response to the variation of the speed of revolution of the main shaft of a sewing machine by the thyristor-ON signals SG19 and the thyristor-OFF signals SG11a. Accordingly, overshoot based on the variation of the speed of the main shaft of the sewing machine can be suppressed at the minimum value while the generation of noises and the generation of heat of the clutch coil can be reduced. |
