GB445772A - Improvements in and relating to electric motor control systems - Google Patents

Abstract

445,772. Automatic control systems. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London. Oct. 10, 1934, No. 29044. Convention date, Oct. 11, 1933. [Class 38 (iv)] [See also Group XXXVII] Web tension.-A control system for apparatus having a motor driven element 11 operating on a strip of material 10, and a reel 12 for the strip, comprises a dynamo-electric machine 18 coupled to the reel, a regulating device 30 for maintaining the current through the machine 18 substantially constant, and a generator 20 connected to the machine 18, the generator 20 having a field winding 24 supplied from an exciter 26 driven at a speed proportional to the speed of the strip so that the strip tension is maintained constant for all strip speeds. Cold steel strip 10 may be wound on or delivered from the reel 12 and passes through rolls 11 driven by a motor 13 the speed of which is adjusted by a field regulator. The regulator 30 may be of the vibratory contact type having an adjustable coil 34 energized in accordance with the current passing through the machine 18 and controlling a field resistance 32, and the generator 20 driven at constant speed by a motor 22, may have an auxiliary adjustable field 25 which serves to give a tension in the strip when the mill is at rest. The Specification, as open to inspection under Sect. 91, comprises also a system in which the motors 13, 18, are supplied from respective Ward Leonard generators. In this arrangement a single controller is provided for controlling the motors 13, 18, simultaneously, the former by regulating its field, and the field of its supply generator, and the latter by regulating the field of its supply generator. This subject-matter does not appear in the Specification as accepted.