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Danotherm Electric A/S
Naesbyvej 20
2610 Roedovre

tel:  +45 3673 2222
fax: +45 3673 2223


cvr. 1012 6061



SIGMA, UL Listed Version

The resistor components consist of fully welded wire wound ceramic resistors, which is a well-known and approved technology.

The base material is corderite, which is a type of ceramic with a very high resistance to temperature changes and the wire is coated with aluminium phosphate to protect the wire and conduct the heat developed in the wire on to the ceramic core. Aluminium-phosphate is stable at 500°C.

The resistor cages comply with IP21 when mounted  vertically (otherwise IP20) giving electrical and thermal protection. The resistors have a nominal load from 430W and upward and are particularly suitable for pulse loads of 10 – 20 times more compared to the nominal load. This is due to the ceramic core material and an extra high weight of wire.

We have developed Thermal Simulation corresponding to all resistor types and resistor values. By using these models we are able to calculate the temperature rises in the resistor wire for all possible load situations. Danotherm offers assistance to customers in finding the optimum solution for any situation.


SIGMA UL Datasheet



Power Range 430W - 4855W (Average)
Pulse Load 25 * PN in 1 sec; 10*PN in 10 s
De-rating Linear @ 40°C: 100% - @70°C: 0.5 * PN
Environmental -40°C- 90 °C
Resistance Tolerance ±10%
Dielectric Strength 2500VAC, 1 Minute
Working Voltage 600V
Insulation Resistance >20M OHM
Protection class IP21, Type 1X
Max surface temperature 350°C
Thermo watch (optional) 250°C
Connection Screw
Climatic EN 60 068-2-2
Vibration EN 60 068-2-6
Approvals UL 508. Listed File E208678
Norms UL 508

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