EEVblog Electronics Community Forum

Electronics => Repair => Topic started by: Chris Wilson on September 10, 2015, 09:46:56 pm

Title: Toroidal mains transformer winding repair
Post by: Chris Wilson on September 10, 2015, 09:46:56 pm

I have a 240 V primary, centre tapped 35V 0 35V at 8.6 amps  (600VA) toroidal transformer that someone has shorted primary to secondary by carelessly drilling a hole in the equipments cabinet and putting a self tapping screw into the winding. (I wonder who this idiot could be? Me? Surely not.... :( Even worse, not realising, I applied mains to it... It had a fuse in the primary though, and damage appears very localised.

I have removed the secondary as it's only about 60 turns. Once I un-tape the primary is it viable to remove a turn or two to get rid of the damaged enamelled wire, which seems to be two or three turns only, carefully fit Raychem heat shrink and solder? The alternative is taking off a huge length of wire. Output voltage is not that critical.  Thanks.

Title: Re: Toroidal mains transformer winding repair
Post by: retrolefty on September 11, 2015, 12:25:09 am

Should work.

Title: Re: Toroidal mains transformer winding repair
Post by: Stray Electron on September 11, 2015, 03:11:16 am

  You should also be able to remove a proportional number of turns on the secondary and keep the correct output voltage if you like.