Re: Buzzing xfmrs

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Alex Crow by way of Terry Fritz <twftesla-at-qwest-dot-net>" <alexcrow-at-blueyonder.co.uk>

Matt,

You can't do this. It isn't possible to reverse a low-votage tranny and get a 
HT one, since

1 - The Mains side is not insulated enough to output more than a few hundred 
V.

2 - The LV side does not have enough turns to be run at 240v - you need a 
certain number of turns per volt, or the core goes into saturation (= nutty 
current draw and buzzing).

3 - Following on from the former, the core is too small for any decent level 
of power - it's designed for the 20 watts or so and that's it. You're not 
going to be able to make a 1kVA plate tranny out of this core.

You need a real plate Xfrmr, or perhaps a microwave oven one - but you need 
to be very, very careful with these since that have no current limit and 
could kill you instantly.

Be careful

Alex

On Sunday 07 April 2002 6:45 pm, Tesla list wrote:
> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <Fucian-at-aol-dot-com>
>
> Hi all, I have been experimenting with other power transformers to see if i
> can get a working plate xfmr.I have a xfmr that is 12 volts at 1.6amps. I
> took a 4.5amp variac and ran the xfmr in reverse. I can get it up to about
> 40 volts in and then it buzzesd and the output voltage refuses to go
> higher.What can I do to stop this?
>
> Matt