GB1094512A - Improvements in and relating to electro-mechanical follow-up control mechanisms - Google Patents

Abstract

1,094,512. Correspondence control systems. CONTRAVES A. G. Nov. 15, 1965 [March 26, 1965], No. 48363/65. Heading G1N. In a correspondence control system a servomotor 1 drives a variable resistor R 1 forming an actual position transmitter, into correspondence with a reference position which is manually set on a variable resistor R 2 . Both resistors are identical in value and are in the same arm of a bridge circuit which is set so that the bridge is balanced when the sum of the effective resistances of R 1 and R 2 corresponds to a value The bridge will therefore be unbalanced in one sense or another depending on whether R 1 +R 2 is larger or smaller than a predetermined desired value S o , and the unbalance voltage will correspond to the difference between the actual position of the servomotor shaft and the desired position. The bridge output is applied to two transistor amplifiers T a , T b and depending on the sense of the unbalance the collector current in one will increase and will decrease in the other. When the collector current in one exceeds a predetermined limit relay K 1 or K 2 will be energized thereby to operate an associated switch K 1 or K 2 to rotate the servomotor 1 in one direction or the other when the said difference exceeds a certain limit #S.