On Mon, Oct 25, 2021 at 05:57 AM, Dave Hills wrote:
Humming" is an artifact of transformer core magnetostriction
Yes, humming, due to magnostriction, used to be a common problem in transformer designs; but, better steel and lamination design has made transformers quieter.
I know, it's a design issue in large power distribution transformers. (They used to hum annoyingly loud... but, are now smaller and quieter too.)
The hum can be a symptom of transformer core de-lamination.
It could also be an indication that the transformer is being run past its current(s) rating(s)... for whatever is causing that. (partly shorted filter cap?)
