Resistors in Wire and Thick-Film from Metallux
The innumerable variations of voltage, current and resistor values frequently create major challenges for the designer of components. The question that often arises is which solution has the least compromises. Metallux AG can actually fall back on the benefits of two technologies: thick-film resistors and wire-based resistors. In practice, it is the application that defines clear specifications for the resistance. Not only do the basic electronic characteristics play a role, spatial conditions, installation orientation and the immediate environment are also important and need to be taken into account when selecting a suitable design
Wire resistors have always been robust, somewhat temperature-proof, almost completely resistant to environmental influences, and, due to the material, capable of withstanding overload. The amount of active resistance material is solely what determines the energy content of the pulses to be converted into heat. For continuous operation, the casing design as well as the type and level of cooling become additional criteria. Limits become apparent when realizing high resistance values and low inductance, as well as in the case of voltages that go beyond the insulation of the wire windings. Solutions can be provided by networks as combinations of serial or parallel circuits.
Preferred applications for wire resistors are brake resistors in machines and systems, cranes, cable and chain hoists, gate drives, earthen resistors and protective resistors. They are also used as loading and preloading resistors for industrial applications and in electrical and hybrid vehicles.
Thick-film resistors stand out through their resistance values in the high G-Ohm range, an electric strength per individual element of about 100 kV, minimal tolerances and excellent stability up to an operational temperature of 80 degrees C.
Combined with a base substrate with high heat capacity and good heat conductance, the thick-film resistors achieve a capacity rating of >300 W. The PLR product range fulfils all requirements of the low voltage directive as well as UL-relevant requirements. PLRC standard resistors with up to 6 kV rated voltage are available for applications in the medium voltage range. In addition, the PLR series can be modified for more advanced applications.
Preferred applications for thick-film resistors are measuring resistors in high voltage generators for industrial and medical systems, in energy transfer and distribution systems, in high voltage measuring and testing equipment and in spectroscopy for material analysis. They are also used in electrostatics such as electrostatic powder and wet paint coating, as well as in the discharging and dehumidification of paper and films during the printing process.
