Medha Transportation LLC

Auxiliary Converters


Medha offers a wide range of auxiliary  converters that are used for powering auxiliary loads in Diesel /  Electric Locomotives, EMUs, DMUs and Metros. Typical loads involved are a combination of blowers, pumps, compressors, lighting, fans,  air-conditioning (HVAC), battery charging and auxiliary power required  by other sub-systems.

Current product offering has a wide  selection of input power type such as AC power from auxiliary winding of traction transformer, DC power from Alternators (rectified) / Traction  Converter or battery banks. Offered converters are available for range  of power rating from 2.5 kVA up to 300 kVA with combination of AC and DC outputs for different loads.

Typically the input power is  processed through a converter stage to provide a stable and controlled  DC bus voltage. The output can be another DC stage (with or without  galvanic isolation) or an AC inverter with regulated output to handle  different AC loads with varying voltage, frequency and power.

Auxiliary Converters also vary by type of cooling and mounting offered. From  natural convection cooling to forced air cooling using extrusion heat  sinks or heat pipe based sinks to water cooled heat sinks and from  under-frame mounting to on-board systems. Type of cooling and mounting  selection is based on customer preference, availability of space,  auxiliary power and availability of filtered cooling air / water.

Typically IGBT switching devices are used with Thyristors, power diodes and  MOSFETs used in specific applications. Polypropylene capacitors are used for improved life and ripple handling capabilities. Magnetics  (transformers and inductors) are used where required based on isolation  and harmonic filtering requirements. Various sensors (voltage, current,  temperature) are used for control, monitoring and protection purposes.  Optic fiber communication is used where required for electrical noise  immunity. Overall control is implemented using state of the art DSPs or  microcontrollers. Complete Auxiliary Converter is typically type tested  to latest IEC standards such as IEC-61287, IEC-60571, and IEC-61373.

As an OEM experienced with design and supply of wide range of Auxiliary  Converters, we can adopt existing designs or design new products to  provide an optimized solution for varying applications. We believe in  providing our customers with customized products that serve their  objectives which are typically a combination of power rating, location,  cooling method, input / output voltage, type of loads, harmonic  distortion requirements, isolation and protection requirements.


Flexibility to suit customer needs
Input : AC or DC or both
Input source : Vehicle transformer, Alternator, Traction Converter DC link, Battery Bank, Third Rail or others
Output : AC or DC or both
Cooling : Natural/Forced air convection or Liquid cooling
Auxiliary loads : Blower,  Pump,  Compressor,  Lighting, Fan, HVAC, Heating, Battery charging, Radiator fan, other vehicle specific sub-systems
Converter mounting : Underframe, On- board, Roof or as Distributed modules
Weight : as per customer requirement
Body : Mild Steel, Aluminum, Stainless Steel