Design Consideration of an Integrated Induction Motor Drive to Replace Auxillary DC Motors in Locomotives

An application requirement from Indian Railways, one of the largest railways in the world, was replacement of 72 V DC small motors in diesel locomotives with squirrel cage induction motor integrated with 3-phase PWM sinewave compact inverter. The motors/inverters were to be mounted inside the locomotives adjacent to the engine (fuel pump, crank case exhauster etc) or in open air near to the wheel (dust blower). This application was critical in nature because loco-failure is very expensive and disruptive. The equipment is required to be very rugged and reliable. Design for such adverse, environmental conditions and high reliability was a technical challenge. This paper discusses the design approach and reports deployment of the equipment in Indian Railways over the last 6 years