transformer hum

[Moze]

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?

 

[anatech]

Hi Moze,
Most often, that is perfectly normal. If you leave it hooked up and on, let it run for 1/2 an hour (say). See if it gets hot. Since I can't hear the hum, I can't tell if it is abnormally high. Chances are that everything is perfectly fine.

-Chris

 

[ctrlx]

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.