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Old 11th Feb 2019, 1:48 pm   #5
kalee20
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Join Date: Feb 2007
Location: Lynton, N. Devon, UK.
Posts: 7,061
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 (250°C-plus) well; doesn't harden or go brittle at low temperatures (-55°C 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 (300°C 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 130°C has a better adhesive.)
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