GB454197A - Improvements in and relating to control systems for electrically-driven strip rolling mills - Google Patents

Abstract

454,197. Control of two motors. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London. Dec. 13, 1935, No. 34666. Convention date, Dec. 13, 1934. [Class 38 (iii)] In a strip rolling-mill having a roll driving motor 13 and a reel driving motor 14, in which the speed of the mill is adjusted by field control of the motor 13 and in which an electricallyoperated device 26 energized by the current input to the motor 14 gives indications of the tension in the strip, the device 26 is automatically calibrated in accordance with movements of the speed controlling means so that its indications are correct for all mill speeds. The motors 13, 14 are fed from a Ward-Leonard generator 15 controlled by a regulator 16 and mill speeds above the basic speed corresponding to full excitation of the generator 15 are obtained by a regulator 17 in the field circuit of the motor 13. The indicating device 26 comprises a moving coil 28 energized from a shunt 29 in the armature circuit of the motor 14, and a stationary energizing coil 27 which is adjusted by a regulator 30. The regulators 17, 16 and 30 are operated by a common handle 18, and are arranged so that when the regulator 16 has been fully operated the regulators 17, 30 are then operated together. Thus the device 26 is automatically calibrated during the controlling range of the regulator 17, and its tension indications are correct for all speeds. The armature current of the motor 14 is maintained constant by a vibratory regulator 22 energized in accordance with the armature current and controlling a field resistance 23. The regulator 22 is adjusted by varying either a resistance 25 in series with its operating coil 22d or the resistance 24 in the armature circuit of the motor 14 across which the coil 22d is connected.