NNTP-Posting-Date: Thu, 19 Dec 2002 02:24:51 -0600
From: Barry Lennox
Subject: Re: welding a transformer core
Date: Thu, 19 Dec 2002 21:26:17 +1300
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On 18 Dec 2002 03:25:33 -0800, firstname.lastname@example.org (N. Thornton) wrote:
>Barry Lennox wrote in message news:...
>> Sounds like some serious BS here. This seemed wierd as I have been
>> using a rewound MOT for a welder, and it spends a fair amount of it's
>> time with no or an insignificant load on it. I had never noticed any
>> "frying" tendencies.
>> Anyway as a sanity check, I took another at random (I have a very
>> large pile of these, SWMBO reckons another microwave coming in the
>> door will sink the house!) and ran it for 15 mins with no load and
>> there is no significant heating that I can detect. When can I expect
>> the frying?
>I think some other explanation is more likely than BS. People
>sometimes think if they get 2 different results on 2 different
>occasions one must be BS, but IME the world tends not to be that
>A useful question might be: how can we explain both being correct?
Yes, I agree, anyway, I ran another 6 MOTs all different, with no load
for 20 mins apiece, some run a little warm, the highest gaining about
20 deg C in that time. Others barely increase at all. There is a (very
rough) inverse correlation between temp rise and core size, but I'm
sure that's not the sole connection.
There certainly is no sign of frying in minutes as you originally
asserted. Can you tell us what sort of MOT did just that? I suspect
there may have been another problem with that MOT, the no-load
condition being a coincidental distraction.