| 摘要 |
<p>1498121 Automatic control of speed MATSUSHITA ELECTRIC INDUSTRIAL CO Ltd 19 Feb 1975 [8 March 1974] 6907/75 Heading G3R A speed regulating system for a rotary machine controlled by a D.C. supply voltage, includes a speed detector providing a time varying signal, dependent upon machine speed, which is combined with a reference timing signal. The combination is smoothed and compared with a reference D.C. voltage which varies with the voltage of the D.C. supply, the result being used to control the rotary machine so as to regulate its speed to a predetermined value, independently of variations in the D.C. supply voltage. As shown, a tachometer 11 provides an output signal whose frequency depends upon the speed of D.C. motor 10. Differentiating and waveform conversion circuits 12, 13 are used to derive, from the tachometer signal, a rectangular waveform whose frequency is dependent upon motor speed and whose amplitude varies with the motor D.C. supply. This rectangular waveform is smoothed by an integrating circuit 14 and compared at 16 with the reference D.C. voltage that is derived from a voltage divider across the motor supply. The result is used to control the voltage across the motor, so as to regulate the motor speed. Waveform converter 13 may include a hook switch and pulse generator, a sawtooth generator and comparator or a phase comparator. Details of the circuits are given in other Figures (not shown).</p> |
