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Old 1st Mar 2021, 9:06 pm   #213
Helder Crespo
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Join Date: Sep 2019
Location: Crystal Palace, London, UK
Posts: 211
Default Re: My first telly TV22

Quote:
Originally Posted by Travellingwave View Post
Hi Helder
I think there may have been two faults , one at the end of the final layer and one in the center of the final layer.

My impression is that the white spirit hadnít reached into the center of the windings. The winding when originally done seems to have had molten wax brushed on ( Iím guessing) so my impression is of an homogenous mixture of wire/paper/wax and no smell of white spirit.

Iím pretty sure that white spirit/varnish would help with reinforcing the insulation at the ends of the windings which is probably where most faults would occur.

As for the thickness , I am probably measuring wax and paper , the paper/wax has the impression of the wire embossed into it , so the actual paper may well be thinner
Hi
Thanks. Wax & paper are definitely not a good combination (think capacitors). Based on your results, I think it is unlikely that any varnish has made it to the central portion of the windings in my lopt, so I agree with you that the protection is mostly at the ends. On the other hand, the white spirit and varnish (given enough immersion time) should be able to infiltrate into the very same areas where humidity (and air) tend to go to, and hence where reinforcement is more important and necessary. I don't know how long my varnished lopt will last, but Argus25's TV22 lopt was "turped & varnished" many years ago (10+?) and is still going strong, whereas my first lopt (left original and untreated) lasted for a few hours prior to developing the dreaded short.
Helder
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