| 摘要 |
905,619. Control of D.C. motors. SCHNEIDER, K., and LORFEVRE, J. Y. March 1, 1961 [March 2, 1960], No. 7483/61. Class 38 (3). [Also in Group XXXV] A D.C. hoist motor M has its armature 1 and field winding 10 each connected to an A.C. source through an associated converter C, R, comprising semi-conductor rectifiers controlled by devices 8, 15, each adapted to supply voltage pulses to its associated converter. A speed responsive voltage and a reference voltage are fed to comparator 17, the error signal being transmitted through a second comparator 19 to the controller 8. The comparator 19 also receives a current-responsive signal to restrict the maximum value of the armature current. The comparator 17 transmits a signal to a bi-stable flip-flop element 23 for determining the direction of field excitation in accordance with the sign of such signal. A function generator 21 varies the field current as a function of the speed so that the product of the speed and flux remains constant above a predetermined speed. When the reference voltage is reduced, the field excitation is reversed and the converter C acts as an inverter, so that the motor is regeneratively braked until it is stabilized at a lower speed. |
