Electronics Weekly
These are hybrid protectors, that combine a MOV (metal oxide varistor) with a gas discharge tube (GDT) in a through-hole disc-style package.
The GDT blocks leakage currents through the MOV that may lead to premature failure, explained the company.
“The comprehensive documentation required to validate this solution – especially in the absence of an existing IEC standard for hybrid over-voltage protection components – highlights our product team’s commitment,” said Bourns’ protection division president Craig Shipley.
Within the range there are devices that protect lines running at from 175 to 555Vac (225 to 745Vdc) that clam to a maximum of 470 to 1,400V respectively at 100A for IsoM5… parts, which have a 40pF end to end capacitance. There are also 50A IsoM3… (30pF) and 200A IsoM8… (50pF) types that cover lesser voltage ranges.
MOVs are gradually degraded while absorbing surges. The highest rated part in this family, the 23mm diameter 9.4mm thick IsoM8-555, can clamp 10 8kA pulses, a single 15,000 pulse, or a single 643J pulse.
Before degredation, leakage at the nominal operating voltage is under 10μA. “Maximum leakage limits after life ratings may exceed 10µA, but will continue to protect at the maximum continuous operating voltage”, said Bourns.
Operation is over -40 to +125°C.
Find the Bourn’s IsoMOV product page here
Last year, KOA Speer Electronics introduced multi-layer surface-mount MOVs handle up to 6,000A.
