GB601003A - Electric regulating apparatus - Google Patents

Abstract

601,003. Automatic control systems. LANGTON, B. K. WARR-. (Sauter Akt.-Ges., Fabrik Elektr. Apparate, F.). April 14, 1942, No. 4912. [Class 38 (iv)] [Also in Group XXXVIII] Temperature.-In an automatic control system in which the response of a differential relay depends on the relative values of resistances associated respectively with controlled and controlling members, both resistances are in series with the same winding of the relay, the current through the other winding, though adjustable if necessary, remaining unchanged during the control operation. As shown, a resistance 5 controlled in accordance with the outside temperature is connected in series with a resistance 51 controlled by the temperature of water in a heating system and with one winding of a differential relay 10 which controls a reversible motor acting on the valve 18 of a heat exchanger by means of which the water is heated. If desired, the motor may also control a third resistance 29 in the series circuit to prevent hunting. The law of control may be varied by adjustment of a resistance 17 in series with the other winding of the relay and by adjusting a resistance (not shown) shunting one of the temperature-controlling resistances. These may be mechanically operated as shown or of a temperature-sensitive kind.. In alternative arrangements, the primary resistance may be manually controlled and the motor may drive a pointer as well as a balancing resistance or several controls may be connected in series, e.g. wind and moisture could be taken into account in controlling a heating system. Reference is made to the use of the invention in any system in which one variable is to control another, the following variables being mentioned : temperature, moisture, pressure, speed, flow, tension and power.