| 摘要 |
950,181. Starting prime-movers. ENGLISH ELECTRIC CO. Ltd May 13, 1960 [May 15, 1959], No. 16724/59. Heading H2H. [Also in Divisions Fl and G3] During starting of a gas turbine the energy supplied to an electric starter motor 1 is increased, and so also is the turbine fuel supply, by fluid pressure responsive devices connected to an hydraulic pressure generator 2 coupled to the starter motor. Rising pressure in the line 22 increasingly closes an obturator 17 in a bleed unit connected to a separate control fluid line 27; this second control fluid acts on the piston 51 of a spring-loaded fuel valve 101, the valve progressively opening as the obturator closes. The starting motor is accelerated by the sequential short circuiting of resistors 10, 11, 12 by pressure-operated switches 4, 5, 6. The motor may be D.C., the resistors being in the supply circuit, or A.C., when the resistors are in the rotor circuit. Another pressure switch 31 initiates a timing device 37 controlling an igniter 36 and its gas supply valve 33, and a further switch 32 opens a second fuel supply valve 39. At self-sustaining speed another pressure switch 14 disconnects the motor and, in the arrangement shown, closes a valve 29 to cut off the control fluid bleed unit. The clutch 26 is also disconnected. At this speed a time controlled cam starts to rotate to progressively close a second bleed 54, so that the fuel supply is further increased to run the turbine up to governing speed. Another bleed valve 53 is controlled by devices (not shown) sensitive to turbine temperatures or pressures, fuel to air ratio or the like. If the motor 1 fails to stop, a final pressure switch 56 shuts down the turbine. In an alternative arrangement the clutch 26 is between the motor 1 and the pressure generator drive so that this continues to be driven by the turbine. In this case the bleed unit is kept in operation up to governing speed, and so obviates cam-controlled bleed 54. The pressure generator 2 may be a positive displacement or a centrifugal pump, with a temperature sensitive valve 21 or other means to compensate for varying viscosity of the fluid, or it may be a total pressure head device (Fig. 2, not shown). This control fluid may be part of the fuel or lubricating oil system.
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