transformer hum


2012-12-02 11:40 pm
I have a 500VA Avel toroidal transfo- I wanted to know if its normal to hear a slight hum eminating from it. It is loudest when power is first applied to it and then it decreases but doesnt go away. I disconnected everything from the secondaries such as rectifier boards and it made no difference...Is this normal?


2012-07-12 10:20 pm
to minimise the hum, firstly mount it on some rubber etc type material which will not compress too much due to weight, go for a 3 to 5mm or so gap from the chassis. secondly dont overtighten the fixing bolt - just enough to hold the txmr in place.