REOhm braking resistors

From compact VFD braking to high-power traction systems.

REO braking resistors safely dissipate regenerative energy across industrial drives, traction and e-mobility, with air- and water-cooled solutions for a wide range of power requirements.

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REO braking resistor

Wide power range

Compact to high-power solutions

Air & water cooled

For different duty requirements

Environmental protection

Options for demanding installations

Application support

Help selecting the right resistor

Product range

Choose by power level, duty and environment.

From compact profile resistors for standard inverter drives to liquid-cooled assemblies for traction, e-mobility and high-power systems.

Sizing tool

Not sure which resistor you need?

Enter your braking duty cycle and pulse power to estimate continuous dissipation and identify a suitable starting point in the REOhm range.

Usage conditions Ambient temperature -15°C … +70°C (above 40°C, reduce continuous output by 5%/10K).
Installation height 0 … 4000 m (above 1000 m, reduce continuous output by 5%/1000 m).

Duty cycle & power

Enter your operating duty cycle directly, or derive it from switching and cycle time.

Minimum duty cycle: 5%.

The peak power the resistor sees while switched on.

Continuous power P = ED% × Pmax. Duty cycle from timing ED% = Ton / SD × 100.

Continuous power, P

100W
BW151 /100
0 W 250 1500 3000 W+
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Resistor rating

See how much overload a given continuous power rating can take at different duty cycles.

Air-cooled: Pmax = P / ED%, overload factor ÜL = Pmax / P.
Water-cooled overload factors are fixed per REO test data and only published from ED ≥ 5%.

Pulse power vs. duty cycle

Air-cooled Pmax Water-cooled Pmax

Full table

Switching time and overload factor at each duty cycle, for the rating above.

Duty cycle ED

Figures are for sizing guidance only and assume standard usage conditions above. Confirm the final rating with REO technical team before specifying.

Applications

Built for demanding braking applications.

REO braking resistors are used across industrial drives, transport, energy and high-performance electrical systems.

High inertia loads

Cranes & hoists

Passenger safety

Escalators & lifts

Traction systems

Railway systems

Harsh environments

Marine & offshore

Energy systems

Wind & energy

High power

E-mobility & test systems

Engineering insight

Practical guidance from the field.

Useful reading for engineers specifying braking resistors, checking duty cycles or avoiding thermal design mistakes.

Specification questions

Frequently asked questions.

Why does braking resistor design matter in modern drive systems?

During deceleration, regenerated energy can raise the DC link voltage. A correctly specified braking resistor gives that energy a safe thermal path, helping protect the drive and maintain controlled stopping behaviour.

Why should I not choose by continuous wattage alone?

Continuous power is only one part of the specification. Peak braking energy, duty cycle, cooling, ambient temperature, mounting position and enclosure ventilation can all change the real thermal load on the resistor.

When should I consider a liquid-cooled resistor?

Liquid cooling is worth considering where power density is high, surface temperature must be controlled, installation space is limited or the resistor must operate in a demanding enclosed system.

Can REO help size the correct braking resistor?

Yes. Send the drive data, braking cycle, resistance requirement, expected energy, ambient conditions and mounting constraints to the REO team for sizing support.

Ready to specify?

Let REO help you choose the right braking resistor.

Share your drive, duty cycle and installation requirements with our engineering team. We’ll help identify the right braking resistor for your application.

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