GB752909A - Electric control system - Google Patents

Abstract

752,909. Magnetic amplifiers. BENDIX AVIATION CORPORATION. March 1, 1954 [April 1, 1953], No. 5954/54. Class 40 (4). In a servomotor system including a magnetic amplifier, a difference between normally equal direct currents through two windings controlling the degree of magnetization of two reactor cores serves to unbalance a Wheatstone bridge comprising a pair of windings on each of the reactor cores, the bridge being supplied with alternating current across one diagonal and feeding a load connected across the other. A signal from a control device 35 is applied to the grid 46 of a two-stage pre-amplifler 24 which is provided with negative feed-back over resistors 61 and 63 to maintain a relatively constant gain. The output is applied to the strapped grids 65, 67 of a double triode discriminator 25 which includes in its anode circuits windings 80, 82 which control the degree of magnetization in the reactor cores 84, 86, Fig. 2. The reactor windings 90, 91, 95, 96 are connected as a bridge 88 to which A.C. is applied at 100, 101 and which is balanced in the absence of a control signal. The phase and amplitude of the bridge output from 103, 104 and the current in field winding 132 is determined by the phase and amplitude of the control signal input relative to the A.C. applied to the anode circuits of the discriminator. Feed-back is provided from the bridge output to the pre-amplifier via a transformer 111 and from a " rate " generator 34 via output winding 202 and grid 46.