GB1032606A - Improvements relating to electronic computer circuits especially for speed control systems for turbo driven alternators - Google Patents

Abstract

1,032,606. Automatic speed control. GARRETT CORPORATION. April 5,1963 [April 6, 1962], No. 13736/63. Heading G3R. An alternator 10 is driven by a gas turbine 11 the speed of which is controlled by the variation of fuel supply by a speed controller 12 responsive to a speed sensor, not shown. The output from a stator 31 is fed to a three-phase supply I, II, III. The real load on the alternator is determined by a computor 21 having an identical unit 33 in each phase their outputs being connected across resistors 42 in series. The current in phase 1 is sensed by a current transformer 35, loaded by a resistor 37, the voltage across which is applied to a transformer 38 having a centre-tapped secondary winding. A network of transistors 43 is connected to the centre tapped secondary winding and gated by the voltages secondary windings of a transformer 41 having a primary winding energized from across phases II, III. The voltage across resistors 42, representative of the real power is applied to an impedance matching emitter-follower 22 having an output across a resistor 61 which is applied through an integrating network 24 or differentiating network 26, selected by a switch 25, to a magnetic amplifier 30 modifying the operation of the speed controller 12. The network 24 is selected for operation in parallel with other alternators to provide a lag or droop characteristic by tending to reduce the fuel supply to the turbine with increase of load. The network 26 is selected when the alternator is operated singly to anticipate change in load by increasing the fuel supply to the turbine. The switch 25 is stated to be operated by a torque-motor.