110VDC to 24VDC Auxiliary Power for Railway Control Systems

Railway vehicles may operate with a 110VDC battery bus, while onboard controllers, communication gateways and monitoring devices require 24VDC power. Connecting these two voltage domains requires careful consideration of battery conditions, load demand and electrical isolation.

The MINGZINC MDF300-110S24 is a 300W isolated DC-DC converter designed to convert a nominal 110VDC input into a 24VDC output, providing an auxiliary power option for control and monitoring equipment.

The Challenge: Supplying 24V Equipment from a Railway Battery Bus

A nominal 110VDC bus does not remain at exactly 110V throughout operation. Battery charging, discharge conditions, cable losses and switching loads can change the voltage available at the converter terminals.

At the same time, multiple auxiliary devices may share the 24V supply. Their combined demand—including startup peaks—must be considered when selecting the converter. An undersized supply or excessive voltage drop in the wiring can interrupt equipment operation.

Engineers therefore need to evaluate the complete power path, from the battery bus to the individual load.

The Solution: An Isolated 24V Auxiliary Supply

The MDF300-110S24 provides a dedicated conversion stage between the 110VDC source and the 24V auxiliary circuit.

Typical power architecture:

110VDC onboard bus → Input protection → MDF300-110S24 → Protected 24V distribution → Control and monitoring equipment

Its 300W rating corresponds to 12.5A at 24V, before allowing for any applicable thermal derating. This gives designers a starting point for calculating the combined power budget of the connected devices.

Input-to-output isolation separates the two power domains. Its benefit depends on the system’s grounding, shielding and wiring arrangement, which should be reviewed during integration.

Potential Applications

The MDF300-110S24 can be evaluated for supplying:

• Onboard communication gateways and network equipment

• Vehicle monitoring and data acquisition devices

• Control electronics and interface modules

• Compatible 24V sensors and relay circuits

For system integrators, a dedicated 24V conversion stage can simplify the use of equipment that operates at a different voltage from the main onboard bus.

Key Integration Checks

Input operating range
Check the minimum and maximum voltage at the converter terminals against the product’s specified input range. Include charging conditions and voltage drop under load.

Continuous and peak demand
Calculate the total continuous load and assess startup current and simultaneous switching. Leave suitable capacity margin for the application.

Thermal conditions
Evaluate cabinet temperature, mounting orientation and available cooling. Apply the product’s derating requirements where necessary.

Protection and wiring
Select suitable input and output protection, conductor sizes and terminal connections. Check voltage drop at the most distant 24V load.

Railway requirements
Confirm applicable insulation, EMC, transient, vibration, fire safety and other project requirements against the product documentation and system validation results.

Discuss Your Auxiliary Power Requirements

Selecting an auxiliary converter starts with the operating conditions of the equipment.

Share your input voltage range, required 24V load, peak current, cabinet temperature and installation requirements with MINGZINC. Our team can help assess the MDF300-110S24 for your application and discuss customization where required.

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