Resistors

REO damping resistors can absorb and temporarily store higher impulse loads.
Thanks to the special winding technology, the wires of the damping resistors are separated spatially and therefore ensure a higher dielectric strength. REO damping resistors are available in the protection classes IP00 to IP 65 and provide a high level of functional safety and service life.

UL resistors: The independent organisation “Underwriters Laboratories” (UL for short) has developed more than 1,300 safety standards Many of these standards are in accordance with the American National Standards (ANSI) and, alongside the requirements for electrical safety for electrical items, they also often take into account additional requirements in relation to flammability

High-voltage resistors are subject to particular requirements as a result of their areas of application. The highest level of functional safety and service life paired with an extreme level of robustness against adverse environmental pressures are as a result essential.
REO high voltage resistors undergo the following tests:

• Climatic fluctuation test
• Vibration and shock test, simulated service life test
• Self-heating measurement
• high-voltage test
• Insulation measurement

When an electric motor works as a generator (electromotive brake), the braking resistor protects the machine from a voltage rise in the DC link. At the same time, the reduction of current leads to a speed reduction of the engine and helps to brake the machine. REO braking resistors achieve better heat dissipation and better dynamic behaviour by filling heat-conducting material surrounding the wound
body. REO braking resistors are short-circuit proof and self-extinguishing. They guarantee a high level of operational safety and are overload-proof in case of short-term loads for your applications (e.g. wind power engineering, railway engineering and automotive engineering).

The charging resistor is a current-limiting resistor for charging and discharging capacitors and limits, for example, the inrush current flowing into the DC link capacitor. For this purpose, the device must be designed for a high single-pulse energy and rated voltage. The inductance of the resistor also contributes to limiting the inrush current, which is why REO wirewound resistors are the right choice.

REO’s liquid-cooled resistors are available in power ratings up to 60 kW, making them significantly smaller than conventional air-cooled resistors. Cooling channels integrated into the heat sink allow for efficient cooling below ambient temperature and provide spatial separation of the current-carrying and liquid-carrying lines – thus ensuring safe operation. Further advantages include high power density, and efficient and low-noise operation.