Snubber Resistors are used in connection with thyristors or switches to protect the components against voltage spikes generated when the current is abruptly cut off by the switching element. To prevent high voltage spikes generated by the inductance "L" the current continues through the RC branch and smoothly switched off.
Although the load in a snubber resistor consists of short pulses the load is considered as a steady state type more than a pulse load. This is due to the fact that the cycle frequency is 50 Hz or more and each pulse only contains little energy compared to the average load.
Snubber resistors protecting high frequency switching components often need to be low inductance types. In other cases where the inductance is less critical normal wound resistor types are used.
Depending on the required power, voltage and inductance Danotherm supply different resistor types.
For small / medium power, voltage and oil cooled constructions CERAMIC WIREWOUND resistors are supplied. These can be supplied as low inductance wound types and as standard types.
HEAT SINK resistors can be used if low hot spots are required in compact heat sink cooled constructions.The HSD/HSF types are wound on flat elements and as such they have relatively low inductance. HS types can be supplied as low inductance types
For thyristors in an AC-DC rectifier normal wound resistors like GRF or ZRF as well as aluminium housed Alpha types are used.
For high voltage applications i.e. HVDC Danotherm supplies resistors from the OHMEGA technology, please require more data