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A method and apparatus for cranking of an internal combustion engine in an AC electric traction motor propelled vehicle using inverters normally coupled to supply power to each of a plurality of AC motors. The inverters have DC input terminals connected between a relatively positive DC bus and a rel

A method and apparatus for cranking of an internal combustion engine in an AC electric traction motor propelled vehicle using inverters normally coupled to supply power to each of a plurality of AC motors. The inverters have DC input terminals connected between a relatively positive DC bus and a relatively negative DC bus and the DC buses are connected to DC output terminals of a rectifier. The rectifier has AC input terminals connected to stator terminals of a synchronous generator. The generator includes a field winding and a rotor connected in driving relationship to a crank shaft of the engine. The vehicle further includes switching apparatus for selectively connecting a battery to the positive and negative DC buses and for disconnecting at least one of the inverters from the AC motor and connecting the at least one of the inverters to supply power to the generator such that the at least one of the inverters is operable to energize the generator whereby the generator operates in a motoring mode to rotate the engine crank shaft to start the engine. Another of the inverters is separately connectable to a pre-lube pump motor for effecting lubrication of the engine prior to starting the engine. After lubricating and starting of the engine, the switch reconnects the inverters to supply AC electric power to respective traction motors of the vehicle.

대표청구항 ▼

[ What is claimed is:] [1.] In a locomotive having a plurality of alternating current (AC) electric traction motors each coupled in driving relationship to a respective one of a plurality of driven wheels of the locomotive, each of the traction motors having excitation windings coupled in circuit wi

[ What is claimed is:] [1.] In a locomotive having a plurality of alternating current (AC) electric traction motors each coupled in driving relationship to a respective one of a plurality of driven wheels of the locomotive, each of the traction motors having excitation windings coupled in circuit with a corresponding one of a plurality of power inverters, the inverters each having a plurality of controllable electric valves for supplying controlled frequency electric power to the corresponding motor by inversion of direct current (DC) power supplied to input terminals of the inverter, the DC power being obtained from rectification of AC power generated at stator winding terminals of an alternator having a rotor connected to be rotatably driven by an internal combustion engine, the locomotive including a battery for supplying power for cranking the engine and for energizing a pre-lube pump motor for lubricating the engine prior to cranking, the improvement comprising:first switching means for coupling the input terminals of at least one of said plurality of inverters in electric circuit arrangement for receiving DC electric power from the battery;second switching means selectively conditionable for coupling the output terminals of at least one of said plurality of inverters to respective ones of the stator winding terminals of the alternator and to excitation windings of the corresponding AC electric traction motor, said second switching means being operable to selectively switch said power inverters into circuit arrangement with the alternator stator windings for supplying power to drive the alternator in a motoring mode for cranking the engine;third switching means selectively conditionable for coupling the output terminals of another of said plurality of inverters to respective ones of the input terminals of the pre-lube pump motor;control means for first energizing the electric valves of said another of said inverters for energizing said pump motor and lubricating said engine, for subsequently de-energizing said another inverters and thereafter energizing the electric valves of said at least one of said plurality of inverters to supply variable frequency excitation to the alternator stator windings for effecting rotation of the rotor thereof and concurrent rotation of the drive shaft of the engine for cranking of the engine when said second means is conditioned for selectively coupling the inverters to the stator winding terminals of the alternator; andeach of said first, second and third switching means being operative to connect output terminals of said at least one and another of said inverters to corresponding input terminals of respective ones of said traction motors.