[Ed_Dinning]

Hi, quite a few possible problems there.

Lams, they may need to be cleaned in a solvent to remove the varnish. They often have an oxide coating to provide a very light insulation. This should not be scrubbed off, but a solvent will be OK on them.
Without doing this you will not get all the lams back in !

The windings were "stick" wound, you may find it easier to add cheeks for your rewind.

Use double insulated wire (Grade 2) and there is then no need to interleave the layers with tissue. You still need insulation between windings !

You might be lucky and see the short at the end of a winding section and you may be able to dribble some varnish or Araldite in there to cure the problem, but be sure to check with a megger after the insulation has cured.


I suspect you will have to remove all windings to be sure you have fixed the problem, so take careful note of the construction.

You can re-varnish if you wish, you could also impregnate with molten candle (paraffin) wax as an easier option.

When re-stacking the lamination's ensure the E & I,s butt closely together or the no load current of the transformer will be higher.

Note that through bolts in the core should be insulated at each end with nylon or fibre washers, the bolts are sometimes also covered in transformer tape. This is to reduce circulating currents.



Feel free to ask as other issues arise, good luck, Ed