| 摘要 |
1,240,089. Control of D.C. motors. INTERNATIONAL STANDARD ELECTRIC CORP. 24 March, 1970 [1 April, 1969], No. l4221/70. Heading H2J. A D.C. commutator motor M having a permanent magnet field is connected in series with a power transistor T1 which is associated with a control transistor T2 whose emitter is connected to a point between the motor M and resistor R1, and whose base is connected to the tapping- point of a voltage divider R2. This arrangement compensates for variations in the supply voltage, and increases the motor voltage with load to stabilize the speed. To ensure that the transistors T1, T2 are saturated for starting the motor, the voltage across the voltage divider R2 is increased by means of a Zener diode D3 or equivalent which is in series with resistor R5 across the supply. Where the motor has started the armature voltage becomes sufficient to desaturate the transistor T2 through the components D1, D2 and R3. In another arrangement, the voltage applied both to the voltage divider R2 and the motor is increased by means of the diode D3, Fig. 3 (not shown). The voltage divider may include circuit elements for providing temperature compensation. |
