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Both Diesel and Electric locomotives use DC auxiliary power supply and small DC motor used for various applications. These DC machines are failure prone (many times leading to failure of complete locomotive) and hence need more maintenance. To increase the reliability of these motors, Medha has developed 3phase AC motor with inbuilt inverter, so that they can directly replace existing DC motors in use. These replacement motors are compatible with input DC voltage and are within the physical space constraints.

Three such examples for Diesel locomotive are:

  • Fuel pump motor (motor + inverter + two pumps)
  • Crank case exhaust motor (inverter + motor + blower)
  • Cyclonic filter dust exhaust motor (motor + inverter + blower)

Inverter consists of a boost DC-DC converter to generate a stable DC bus voltage and a 3-phase inverter to drive the AC motor. MOSFETs and IGBTs are used as switching devices and natural convection is used for their cooling. DSP is designed for all controls, monitoring and fault diagnostics of both DC-DC converter and inverter.


  • Accepts wide input voltage range (from auxiliary generator/ vehicle battery) : 50-90 VDC
  • Operates at very low voltage situations during Engine cranking
  • Motors with class-H insulation, IP65/IP54 protection (inverter/motor), >80% combined efficiency
  • Protections for following situations: under voltage, over voltage, overloads, short circuit, reverse polarity, over temperature as per IEC 60571 and IEC61287.

Cyclonic Filter Dust Exhaust Motor

Fuel Pump Motor

Crankcase Exhaust Motor

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R & D Centre

Behind Mint Compound, Cherlapally, R.R.Dist,
Hyderabad - 500 051 Telangana, India.
Phone: +91-40-6723 7000; Fax: +91-40-2726 4144

Corporate Identity Number:  U31103TG1984PTC004436

MEDHA SERVO DRIVES PVT. LTD. P-4/5B, IDA, Nacharam, Hyderabad - 500 076 Telangana, India
Phone: +91-40-2717 1101; Fax: +91-40-2715 4706