Power Range

  • < 100W
  • 100W < P < 1kW
  • 1kW < P < 2kW
  • 2kW < P < 5kW
  • 5kW < P < 50kW
  • > 50kW

Cooling Method

  • Convection
  • Liquid
  • Ventilator
  • Heatsink


  • Cable
  • Box
  • DIN term
  • Stud
  • Screw
  • Sold
  • AMP
  • PCB

Protection Class

  • IP00
  • IP10
  • IP13
  • IP20
  • IP23
  • IP44
  • IP50
  • IP54
  • IP60
  • IP65
  • IP66

UL - Approved

  • Yes
  • No


  • Balance
  • Ballast
  • Brake
  • Charge
  • Crowbar
  • De-charge
  • Dump
  • Filter
  • Heater
  • Loadbank
  • NER
  • Shunt
  • Snubber


Frequently asked questions about power resistors

  • What is a resistor?

    A resistor is a passive electrical component that influences the current and voltage in an electrical circuit. The unit for resistance is Ohm, symbol Ω, given by the German scientist Georg Ohm who published his book ‘Die galvanische Kette’ in 1827. In this book, the linear equation R = U/I indicates that the current in a wire is directly proportional to the applied voltage and inversely proportional to the resistance of that wire.

    • What is a power resistor?

      A power resistor is a resistor that can dissipate a relatively high power. Power resistors can be used in applications where they continuously dissipate (high) power or in applications where the power load is (very) high but only during a short time.

      • Why use a resistor?

        Reasons for using a resistor are numerous; to limit the current in a circuit, fix voltage levels, create a frequency-dependent filter (together with other electrical components), and have an electrical power load in a circuit. Many Danotherm power resistors are used in drive systems to protect the electrical system against high voltage levels when the drive is braking.

        • What is a resistor made of?

          Metal alloys are the most common material for Danotherm resistors. The alloy can be a wire that is wound on a support, or it can be self-supporting. It can be a metal alloy sheet that is punctured with a pattern. Some resistors are made with conductive foils (thick films).

          • How to make a resistor?

            The resistor element (conductor) can be placed on a support, for example, a wirewound resistor, which has ceramic support where the wire is wound on. The ends of the resistor element are connected to electrical terminals. Other resistors have a casing where the resistor elements are fitted in. Some resistor types have thermally conductive filling material to expel the heat that is generated in the resistor element to the outside.

            • What does a resistor do?

              A resistor controls either voltage, current, or both in an electrical circuit.

              • What is a resistor used for?

                Resistors are used in many applications. They are used as brake resistors, inrush current limiting resistors in electric circuits, voltage sharing resistors in capacitor banks, energy dump resistors in (wind) turbines, filter resistors in electronic inverters, pre-magnetize resistor for power transformers, neutral earthing resistors in distribution stations, test or measuring resistors to test the conditions of an electric circuit.

                • How to test a resistor?

                  The most common test or measurement is that of the resistance value. All resistors are produced with a specific nominal ohm value. This is the value indicated on the resistor. The real Ohm value will deviate from this value. The difference (in percentage) is the tolerance. By using a simple electronic multimeter, the ohm value is measured. 4-point Ohm meters or a Wheatstone bridge are used for more accurate measurements.

                  • What is dynamic braking?

                    Dynamic braking is the dissipation of excess energy coming from an electromechanical drive system that generates electrical energy in braking mode. An electromechanical drive system that is braking is generating electricity. The electricity will flow back into the electronic drive inverter, causing an increase in the system voltage. This is potentially harmful to the electronic components of the inverter and must be dealt with. The brake resistor dissipates this excess energy and keeps the voltage below safe values.

  • What are resistors used for in wind turbines?
    • Dump resistors (LVRT); Low Voltage Ride Through is the capability of modern wind turbines to operate during disturbances in the grid. Minor disturbances happen often but usually are very short. If the turbine cannot feed (part of) the energy in the grid, the surplus is dumped in a resistor. Regulations differ from country and or energy company. The regulation is fixed in grid codes.

    • Filter resistors: the voltage frequency of the turbine needs to be converted to the same frequency as the grid. For this, semiconductor switches are used. The switching of the semiconductors causes higher harmonics which are bad for the quality of the power. The filter (the resistor is part of the filter) improves the power quality.

    • Charge resistors: They limit the current in an electrical circuit to protect other components from harmful over currents.

    • Discharge resistors: they safely unload the electrical charge in capacitor banks to safe voltage levels when the inverter needs to be serviced or decommissioned.

    • Pitch control: (brake resistors). Sometimes this is done by hydraulics, but electrical brake resistors are needed when it is done.
    • What are resistors used for in electrical vehicles?

      They are mainly used to dissipate regenerated electrical energy from the motor and go into the electronic drive inverter during braking. If possible, this regenerated energy will be used to charge the battery. However, there are conditions when the battery cannot take (all) the energy, e.g., when it is cold or when the battery is fully charged.

      • What information is needed to select the right resistor?

        Ohm value, working voltage, load profile (power-versus-time), way of cooling, connections, ingress protection rating, environment, and application are the main parameters for selecting the appropriate resister. Additional information might be needed concerning the size of electrical terminals, the flow of liquid coolant and coolant connection size (if applicable), auxiliary systems (temperature sensors, pressostats etc.)