Improvements in control systems for associated dynamo-electric machines particularly applicable to rolling mill drives

摘要

553,082. Control of D.C. motors. WESTING- HOUSE ELECTRIC INTERNATIONAL CO. Jan. 28, 1942. No. 1194. Convention date, Jan. 29, 1941. [Class 38 (iii)] In controlling a motor 4 and an associated dynamo-electric machine 2 which is connected in series with a booster 8 excited in accordance with the speed of the motor 4, in order to extend the speed range of the dynamo-electric machine, as for example in an electric rolling mill device as described in Specification 515,103, the inductance of the booster field 38 entails a sluggish response of the dynamo-electric machine 2. To overcome this a forcing generator 12 is connected in the booster field circuit and excited in accordance with the difference between a quantity responsive to the speed of the motor 4, e.g. the voltage of a tachometer generator 10, and a quantity responsive to the armature voltage of the dynamo-electric machine 2. These two quantities may be applied respectively to field windings 66, 52 of the forcing generator. To eliminate the effect of the armature resistance of the dynamo-electric machine an excitation field winding 58 proportional to the current therein may assist the latter quantity. The dynamoelectric machine may act as a motor to drive a reel or as a braking generator and is regulated to constant armature current. The booster field circuit may be connected across the generator 10 or across the main source 6 ; in the latter case a resistance in that circuit is adjusted simultaneously with the field resistance of the motor 4 to change the booster voltage with the change in motor speed.