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Danotherm Electric A/S
Naesbyvej 20
2610 Roedovre

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


cvr. 1012 6061




The SIGMA resistor family is a traditional Brake Resistor family from Danotherm.

It covers a power range from 100W to 5kW average loads and it is a popular economically type of brake resistors capable of fulfilling many brake resistor needs. 

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 which can withstand high thermal stress 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 IP20 (IP21 for UL versions)  giving electrical and thermal protection  The resistors having a nominal load from 100W - 5kW are particularly suitable for pulse load of 10 – 20 time or more compared to the nominal load because of the ceramic core material and an extra high weight of wire.

We have developed THERMAL MODELS corresponding to all resistor types and resistor values. By using these models we are able to calculate the temperature rise in the resistor wire for all possible load situations. Danotherm offers its assistance to its customers to find the optimum solution for any situation.

SIGMA Ceramic Brake Resistors

This resistor family ZRF 55/ ... 08X  is an updated version of the original brake resistor famely that has been produced by Danotherm since 1990.
The power range is from 100W to 5kW continuously.  

SIGMA, UL Listed Version

SIGMA ZRF 55/… 0A8X is a range of Ceramic Wire Wound Brake Resistors mounted in IP21 / Type 1X housings and equipped with Thermostats for temperature warning.


SIGMA Resistors mounted in a sheet metal housing and cooled with ventilators.


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