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Old 11th Feb 2019, 1:48 pm   #5
Join Date: Feb 2007
Location: Lynton, N. Devon, UK.
Posts: 5,266
Default Re: PTFE tape for transformer insulation

I wouldn't use it, except on a very temporary job.

PTFE is super stuff in the right place, it withstands high temperatures (250C-plus) well; doesn't harden or go brittle at low temperatures (-55C and below); has very high insulation resistance; very low dielectric loss.

But, as G4_Pete says, it yields easily under pressure. No good when you have another winding on top, pressing down! And as Dave points out, at very high temperatures (300C or more, so fault conditions in a transformer) it gives off seriously nasty fumes. Google 'PTFE Flu.'

Agree with Argus - Kapton is much better. Or Nomex. (The yellow polyester tape, eg Scotch type 57 is much cheaper and although rated to only 130C has a better adhesive.)
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