| 摘要 |
1,179,567. Rectifying; control of D.C. motors. HEBERLEIN & CO. A.G. 3 Feb., 1967 [3 Feb., 1966], No. 5398/67. Headings H2F and H2J. [Also in Division G3] A circuit for controlling the supply of power to a series motor 16 comprises a thyratron or thyristor 1, the control electrode of which is connected to a capacitor 8. The capacitor is charged during each cycle in two steps, the charging rate during the first step being greater than that during the second step, the potential at which the charging rate changes being controlled in dependence on motor load so that the speed remains constant. As described, capacitor 8 charges rapidly at the beginning of each positive half-cycle of the A.C. supply at 3 until the voltage at the junction of resistors 13, 14 becomes sufficient to turn on transistor 12, when diode 11 becomes non-conductive. The charge continues at a lower rate dependent on the setting of variable resistor 7 until a breakdown diode or neon tube 9 breaks down, triggering thyristor 1 which passes current for the remainder of the positive half-cycle. Resistor 17 in series with the motor 16, diode 18 and capacitor 19 provide a compensating circuit which results in the speed/torque characteristic of the series motor 16 becoming similar to that of a shunt motor.
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