Re: Isolation transformer - MOT?

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

Original poster: "Allanh by way of Terry Fritz <twftesla-at-qwest-dot-net>" <allanh-at-starband-dot-net>

If you connect two MOT's back to back you will find the
output voltage is about 75% of the input, that is 120 volts in and 90 out,
with no load. As the load increases, the output drops. This is due to the
shunts inside the MOT.
I've converted severl MOT's just the way you described and it works very
well, with almost 95% efficiency, with a 500 VA load, and the shunts
removed.

Good Luck,

allan

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Sunday, May 26, 2002 10:45 AM
Subject: Re: Isolation transformer - MOT?


> Original poster: "S & J Young by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<youngs-at-konnections-dot-net>
>
> Matthew,
>
> Yes, you can make an isolation transformer as you described it.  It will
> probably not be as efficient as commercial ones due to skimping on the
core
> to save manufacturing costs.  The other easier way to make an isolation
> transformer is to run a pair of MOTs back to back:  hook the secondaries
> together, run power into one primary, and take it out of the other
primary.
> Wastes a few more watts & is heavier, but it saves a lot of work.
>
> --Steve
> ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Saturday, May 25, 2002 9:38 AM
> Subject: Isolation transformer - MOT?
>
>
> > Original poster: "Matthew Smith by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <matt-at-kbc-dot-net.au>
> >
> > Hi All
> >
> > The joys of living in a small country town!  Only two shops sell
> > microwave ovens and only one does their own repairs.  The result is a
> > stream of similar ovens (Panasonic) with *identical* transformers, caps,
> > diodes, etc.  (Collect enough and you can make a working one.)
> >
> > Not the real reason for my post though...
> >
> > If I have two identical transformers, what is the feasability of
> > removing the secondary from one and replacing with the primary from the
> > other?  Would this give me a decent 1kVA isolation transformer?
> >
> > I rather like the idea of running my bench supply through one with a
> > heck of a lot of filtering - stop SSTC signals showing up where they're
> > not wanted.
> >
> > Cheers
> >
> > M
> >
>