That burning smell in transformer

transformer

avr1

When I plugged in a 250VA load to the left transformer. I can smell something burning and the case is super hot.

What causes the burning smell? What part of transformer can produce burning smell?

And does it mean the transformer is already ruined? If one would continue using it.. maybe it can fail suddenly or does the burning not produce permanent damage?

Both are rated 500VA.. but I think the small one that has smell is not a real 500VA capacity transformer. It is inside a voltage regulator. Maybe a voltage regulator especially boost buck type doesn't need a full capacity transformer because it's only adding or subtracting some voltage?

Best Answer

The burning smell is the insulation of the winding conductors burning and is generally indicative of irreparable damage. It may still function, for a while, but has been severely compromised. Further failure often results in flames...