| 摘要 |
<p>A motor speed control device comprising a threebrush motor (10) having first (11), second (12) and third (13) brushes, an amplifying device (20) having output electrodes connected to said third brush in a circuit to control the energization of said motor between said first brush and said third brush and having an input electrode, said amplifying device controlling the current flow from its output electrodes in accordance with the signal applied to said input electrode, first means (33) preferably comprising a resistance and a diode (34) to apply a signal derived from said second brush (12) to said input electrode to regulate the speed of said motor and second means (32, 130) preferably comprising a variable resistance to apply a signal derived from said first brush (11) or from said third brush (13) to said input signal to regulate the speed of said motor. The device can be implemented without any need of modifying the motor and achieves a constant motor speed under varying load conditions.</p> |
