Part 431KD20 Varistor
Part 431KD20 Varistor
These varistors were protecting a transformer when they died. The transformer was protected as the fuse blew – thanks to the varistors. Credit: bhungy
Archive for the ‘Varistor’ Category
Part 431KD20 Varistors blow
Sunday, January 24th, 2010Varistor on UPS cracks
Friday, December 11th, 2009
Board with blown MOV
Closeup of failed MOV
The burned part shown appears to be a MOV (Metal-oxide Varistor). The purpose of a MOV is to have a very high resistance until a certain voltage is reached at which point it will conduct current, in this case from “Hot” to “Neutral.” This property is useful for surge protectors. Original poster says this UPS was involved in an electrical fire. Credit: