GB988794A - Electrical servo-system operating on an extended speed range - Google Patents

Abstract

988,794. Measuring pressure electrically. BENDIX CORPORATION. March 28, 1962 [April 4, 1961], No.11937/62. Heading G1N. In a closed loop servo system wherein a control signal from a transfucer is fed through an amplifier to a servomotor to electromechanically rebalance the system, an electrical anti-hunting feedback signal is derived from a rate generator coupled to the servomotor, the mechanical characteristics of the combination being such as to produce proportionately more feedback at low levels of the control signal than at higher levels. As shown (Fig. 1), a bellows 4 measuring ambient atmospheric pressure to give an indication of the altitude of an aircraft, is mechanically coupled to the armature of an E-shaped pick-off 13 producing a signal from the secondary windings 18 which is amplified to energize a servomotor 103, repositioning the E-shaped core 19 of the pick-off 13 to eliminate the control signal. The motor 103 is also coupled to a rate generator 111. For low values of the control signal, the speed of the motor 103 and the output from generator 111 are both proportional to the control signal, giving a high feedback voltage producing high damping. As the motor speed reaches its maximum value, the incremental change in feedback voltage is considerably reduced, thereby reducing the value of the damping. The initial high damping value is adjusted by a variable resistance 130 in the feedback loop.