| 摘要 |
PURPOSE:To remove a noise at the normal time by providing a time constant circuit, thereby effectively starting a motor. CONSTITUTION:When a start signal 18 becomes a L level, a transistor 22 is turned OFF, and a control signal 19 becomes a high voltage. Simultaneously, a transistor 17 is turned OFF, a charging from a constant-voltage source 16 through a resistor 15 to a capacity 14 is started, and a signal 20 gradually rises. When a motor 1 rotates one revolution, a FG signal generated from a generator 2 is added to the signal 20. An amplifier 3 outputs the FG signal to a frequency/ voltage converter 4 in this step. Since the rotation of the motor 1 sufficiently rises at this time point, the FG signal is correctly detected. Noise when the FG signal is detected is removed by a low pass filter which has the capacity 14 and a resistor 13. |
