| 摘要 |
PURPOSE:To change-over motor speed by means of switches by applying the output signals of a speed generator to the first input terminal of a comparison circuit and line voltage to the second input terminal through the main switch or the by-switch. CONSTITUTION:A speed generator 26 detecting the number of revolution of an upper shaft 24 is connected to the first input of a comparison circuit 28, and a foot switch 29 and a foot switch 30 to which a resistor 23 is mounted are connected to the second input. The output of the comparison circuit 28 each actuates a clutch 19, a brake 20 and press-down-and-up and cotton-cut solenoids 34, 36 through a control circuit 31. Thus, when the switch 29 is at ON, the clutch 19 and the brake 20 are controlled so that the voltage of the speed generator 26 becomes the same as line voltage, and when the switch 30 is ON both are controlled so that the voltage becomes the same as voltage than the line voltage. Consequently, speed can be controlled by changing over the switches 29, 30. |
