Hi folks,
I was winding a high voltage (20 kV 120 kHz) secondary for a push-pull transformer, using 33 swg (0.25mm diameter) copper wire when the inevitable happened - the wire broke. I've completed 41% of the winding. I would like to know if I can repair the break by scraping off the enamel along 1 cm nearest the end of the broken winding and do the same with the free end of the spool wire, then lay these scraped ends parallel to each other:
_________________
_______________________
then twist these together and solder the joint. Finally, wrap the soldered connection with plumber's PTFE threading tape a few times. I believe the breakdown voltage of a single layer of the tape, even though its very thin, is 4 kV DC. For interlayer separation I'm using a turn of kapton tape (the golden coloured stuff) on top of which I'm wrapping a turn to 1 1/2 turns of 0.5mm thick acetate film. The ends of the acetate being stuck to the winding with more kapton tape. The completed transformer will be immersed in mineral oil (medicinal paraffin, aka Nujol).
If such a repair is safe, is there a limit to how many breaks can be fixed in the same winding in this manner ?
(The red parts of the wires in the drawing above, should be aligned. For some reason, even though I put in the required spaces, the text editor refuses to keep them aligned !)
I was winding a high voltage (20 kV 120 kHz) secondary for a push-pull transformer, using 33 swg (0.25mm diameter) copper wire when the inevitable happened - the wire broke. I've completed 41% of the winding. I would like to know if I can repair the break by scraping off the enamel along 1 cm nearest the end of the broken winding and do the same with the free end of the spool wire, then lay these scraped ends parallel to each other:
_________________
_______________________
then twist these together and solder the joint. Finally, wrap the soldered connection with plumber's PTFE threading tape a few times. I believe the breakdown voltage of a single layer of the tape, even though its very thin, is 4 kV DC. For interlayer separation I'm using a turn of kapton tape (the golden coloured stuff) on top of which I'm wrapping a turn to 1 1/2 turns of 0.5mm thick acetate film. The ends of the acetate being stuck to the winding with more kapton tape. The completed transformer will be immersed in mineral oil (medicinal paraffin, aka Nujol).
If such a repair is safe, is there a limit to how many breaks can be fixed in the same winding in this manner ?
(The red parts of the wires in the drawing above, should be aligned. For some reason, even though I put in the required spaces, the text editor refuses to keep them aligned !)