The Cyber-Spy.Com Usenet Archive Feeds Directly
From The Open And Publicly Available Newsgroup
This Group And Thousands Of Others Are Available
On Most IS NNTP News Servers On Port 119.
Cyber-Spy.Com Is NOT Responsible For Any Topic,
Opinions Or Content Posted To This Or Any Other
Newsgroup. This Web Archive Of The Newsgroup And
Posts Are For Informational Purposes Only.
From: John Woodgate
Subject: Re: welding a transformer core
Date: Thu, 19 Dec 2002 14:42:38 +0000
Organization: JMWA Electronics Consultancy
Reply-To: John Woodgate
NNTP-Posting-Date: Thu, 19 Dec 2002 16:53:47 +0000 (UTC)
X-Newsreader: Turnpike (32) Version 4.01 <5Z8C9wtxbnpWyFnyfFzqmVF739>
I read in sci.electronics.design that Gibbo
wrote (in <firstname.lastname@example.org>) about 'welding
a transformer core', on Thu, 19 Dec 2002:
>Someone mentioned only UK posters talking of overheating. This got me thinking.
>So I ran a MOT wth no load from a variac.
>At 250 volts within 10 minutes it was hot. Very hot. It was also pulling 3.2
>amps. I didn't bother measuring the waveshape or phase of the current to
>indicate whether it was saturation.
Well, it wasn't Scotch mist. Or microwaves! You can be assured that it
was saturation; the next experiment proves it.
>I then ran it at 220 volts. After 10 minutes it had hardly warmed. Mains
>current = 0.9 amps.
>UK uses 230 volts on paper. It's 240 volts in practice. Rest of Europe is 230
>volts on paper, 220 volts in practice.
>Looks like a saturation issue.
>I'm not saying this explains every instance and I don't have the time right now
>to look into it any further.
Saturation is a very significant factor, which I addressed in my post
listing the reasons for large temperature rises.
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
Interested in professional sound reinforcement and distribution? Then go to
PLEASE do NOT copy news posts to me by E-MAIL!
Go Back To The Cyber-Spy.Com
Usenet Web Archive Index Of
The sci.electronics.design Newsgroup