GB828111A - Improvements in constant output control systems - Google Patents

Abstract

828,111. Automatic speed-control systems. GENERAL ELECTRIC CO. Aug. 29, 1957 [Aug. 31, 1956], No. 27226/57. Class 38 (4). [Also in Group XXXIII] A control system to provide constant action of a load for a given input signal by providing constant output of a power motor connected to the load for said given signal, wherein an input signal is coupled by means of a multiplier to the power motor, is characterized by a divider, means for feeding the output of said multiplier to said divider, means for also feeding a signal indicative of the output of said power motor to said divider, and means for feeding the resultant output of said divider back to said multiplier whereby, when the output of said divider is equal to the ratio of the multiplier output and the latter signal, the output of said power motor is constant for said input signal. As applied to a machine tool, an alternating input voltage # 1 excites the stator winding 14 of a resolver 12 to induce an output voltage e in a rotor winding 16, voltage e operates a servo 20 consisting of amplifier 22, motor 24, and feed-back signal generator 26 to operate a motor 24 to produce an output # 0 which may be either speed or angular movement for application to a machine tool 25 wherein the load may vary with the hardness of the material to be machined. An anti-hunting tachometer may be incorporated if necessary. The output signal e is fed also to the amplifier 32 of a divider 30 to operate a motor 34 which turns rotor 16 of resolver 12 to increase the voltage e. Motor 24 also drives through shaft 35 an A.C. generator 36 which produces an output K# 0 proportional to # 0 to energize the stator winding 37 of a resolver 38, causing a voltage v to appear at the rotor winding 39. This is fed to amplifier 32 through an anti-hunting tachometer 40. Motor 34, in addition to turning rotor 16, also turns rotor 39 until the output of amplifier 32 is zero, i.e. when e - v = 0. In an alternative arrangement the output K# 0 may be derived from a further resolver, the stator of which is energized by a constant A.C. voltage source, the rotor being turned by a connection to shaft 35.