| 摘要 |
892,096. Control of D.C. motors. STARKSTROM - ANLAGENBAU ERFURT VEB. March 31, 1958 [Aug. 28, 1957], No. 10211/58. Class 38 (3). [Also in Group XXXV] An electric motor MF driving a double-cage lift is supplied from a Ward-Leonard generator G having an amplidyne exciter A, the motor being controlled to provide periods of constant acceleration, full speed, retardation, and creeping speed during a working cycle. Initially, a main winding I of the exciter is connected through a potentiometer P1 to a D.C. source PN and is assisted by a speed-responsive winding VI energized from a motor-driven tachometer generator TG. An exciter field winding V is energized in accordance with the acceleration of the motor through a transformer T1 and amplifier 24, and opposes the winding I for maintaining the acceleration constant. When the speed of the motor has increased to a predetermined value, the voltage of the tachometer generator exceeds a bias voltage provided by potentiometer P2 and rectifiers G1, so that a field winding II of the exciter is energized to oppose the winding I and to limit the speed of the motor. The lift is then driven at a steady speed under the control of the field windings I and II until the cages reach predetermined positions in the shaft whereupon the windings I, V are reversed and the winding II is disconnected for retarding the motor. When the voltage of the tachometer generator becomes less than that derived from potentiometer P3, a field winding III of the exciter is energized to oppose the winding I and to cause the motor to operate at creep speed. After the motor has stopped, a field winding VII of the exciter is energized to compensate for residual flux in the generator G. In addition, the exciter A has a compounding field winding IX which is energized in accordance with the motor current, and a field winding VIII for compensating for changes in the current. A further stabilization field winding IV is energized by the amplifier 24. |
