Patent GB-703263-A (GB)
Title: Improvements in or relating to electrical power transmission systems
Inventor: BROWN JAMES KINGHORN
IPC: H02P9/04
Filed: 1950-10-19
Abstract: 703,263. Transmitting mechanical power. METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. Oct. 18, 1951 [Oct. 19, 1950], No. 25537/50. Class 38 (4) In a power transmission system of the kind in which a prime-mover T, such as a gas turbine or Diesel engine, drives a locomotive or other load through an electrical transmission comprising generators G1 ... G3 and traction motors M1 ... M6, means representative of the energy intake of the prime-mover control means responsive to the speed of the prime-mover so as to regulate the speed to a desired value, regulation being effected either by control of the generator output, or by control of the input energy to the prime-mover, according as the energy input is at or below a reference value. In the arrangement shown, a fuel regulator FR controls, through a reversiote servomotor FSM, the fuel valve FV of the gas turbine T and simultaneously adjusts potentiometers 37, 61 in control circuits for the fuel regulator and a generator output regulator OR. A master controller MC controls the maximum power output of the plant, whilst a tractive effort regulator TER limits the current flowing in the generatormotor loop. The regulators FR, OR, TER may comprise dynamo-electric machines, magnetic or electronic amplifiers, but are preferably of the vibrating type described in Specification 703,268, [Group XXXVII], the regulator having coils OC FR1 and OC FR2 controlled by the potentiometers 37, 61, which also control coils OCOR1 and OCOR2 of regulator OR. Regulator TER has a coil FTER fed through a rheostat R2 operated by the master controller and a coil OCTER energized in proportion to the motor current. The regulators TER and OR control the excitation of a field EF2 of an exciter machine E for the generators G1 ... G3, the machine having another field EF1 which is energized over a rheostat R1 of the master controller, whilst an opposing " series " field EF3 imparts to the generators a drooping characteristic. potentiometer 34 fed over rectifier 32 from a @chometer generator 30 provides a voltage proportional to the speed of the turbine the difference between this voltage and the voltage from potentiometer 37 energizing regulator coils OCFR1, OCOR1 in such as sense as will cause their regulators to govern for constant turbine speed. Which of the two regulators is effective is determined by the setting of the servo-adjusted potentiometer 61 in relation to the setting of a potentiometer P operated by the master controller, whereby coils OCFR2 or OCOR2 (in series with oppositely poled rectifiers 64, 66) are' selectively energized in accordance with whether the opening of the fuel valve is greater than, or less than, a reference value corresponding to the setting of potentiometer P. A condenser 68 may be provided, in accordance with Specification 703,265, so that upon demand for more power by the master controller, the control system injects an extra quantity of fuel which will be commensurate with that required to accelerate the turbine. A temperature variable bridge, responsive to the temperature of the exhaust gases of the turbine controls energization of a coil OCFR4 of the fuel regulator to limit fuel input when the exhaust temperature is excessive. A restraint circuit, as described in Specification 703,266 and comprising windings OCFR3, OCOR3 energized over rectifier 84 when the output voltage of potentiometer 61 (representative of the rate of fuel intake) exceeds the voltage across a non-linear resistor 83 (representative of the maximum permissible fuel intake by the turbine at its running speed), prevents excessive fuel input. In a modified arrangement a single regulator replaces the fuel and output regulators. Specifications 703,264 and 703,267, [Group XXVI], also are referred to.