Modern electrical equipment requires a stable voltage supply with low levels of harmonic distortion. However, electrical installations often generate interference causing disturbance to electrical networks. This leads to various problems such as:

• Overheating
• Malfunctioning of control or remote monitoring systems
• High currents in the different phase or neutral lines
• Resonance problems.

Filtering resistor 130 kW pt – 347 ohms

As a result it is necessary to have harmonic filters. These are basically composed of capacitors and inductors. The addition of a resistor allows:

• Easier filter tuning at installation,
• Widening of the pass band,
• Greater tolerance of temperature changes in the components.

DESIGN OF POWER RESISTORS FOR HARMONIC FILTERING

1. Power dissipation :

Energy is partially stored in the material of the active heating elements. The remaining energy has to be transferred to the surroundings either by radiation or by convection. This depends on :

- the design of the resistor
- the surface characteristics of the heating elements
- the temperature difference between the ambient air and the heating elements

2. Resistance value:
The specification must indicate the nominal value of the resistor.

3. Breakdown Voltage:
The resistor must be designed to respect minimum physical separation distances between the different components to avoid arcing (enclosure to components; enclosure to bench; enclosure to frame; connectors etc.).

4. Inductance:
Connectors have to be carefully designed and examined as high current transients can create undesirable electromagnetic forces.

5. Miscellaneous :
Environmental and site conditions (any specific pollution, seismic activity, corrosive substances, wind, altitude etc.).

To define specific parameters related to your requirements, please consult us.