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From: "Phil Allison"
References: <email@example.com> <firstname.lastname@example.org>
Subject: Re: How to test a power t-former for Amp rating?
X-Newsreader: Microsoft Outlook Express 5.50.4522.1200
Date: Thu, 21 Nov 2002 09:35:52 +1100
NNTP-Posting-Date: Thu, 21 Nov 2002 09:25:45 EST
Organization: Telstra BigPond Internet Services (http://www.bigpond.com)
"Tom Bruhns" wrote in message
> I agree with Phil, that you can make a very good esitmate based on the
> winding resistance. You can even do better than that, though.
** The primary resistance determins the VA of the whole tranny, the
individual VAs of the various secondaries are more difficult.
> It's heat--temperature--(and the consequent destruction of the
> insulation) that causes transformers to fail.
** Almost all makers work on a 50 to 60 degress C temp rise above
ambient for their ratings. This gives an internal max temp of about 100
degrees or so which standard enamels cope with just fine. Any more and the
tempco of copper ruins the regulation factor to much.
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