Re: Homemade Trasformer

To: tesla-at-pupman-dot-com
Subject: Re: Homemade Trasformer
From: "Megavolt Nick" <tesla-at-fieldfamily.prontoserve.co.uk> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Mon, 14 Feb 2000 05:31:40 -0700
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

Hi Ross,
> Hi all,
>
> --This is prolly about the thousanth time this has come up on the list,
> but a few more posts can't hurt--
>
> I am thinking of building my own transformer for my coil - not that I
> belive it'll be close to as good as a pig, but want to do it myself
> (yeah, i'm nuts).
Custom psus are great - a local xfmr co. are doing a pair for me at the
moment.

>  I found dad's old EE book and ran the numbers, and I
> should only need 120 turns in the primary to choke the 240V/60hz mains
> current (as long as the core is bigger then 14 in^2), and 6000 or so
> turns in the secondary to give 12 kV.
14in^2 !!!!! - that is huge, this psu is gonna be about 28kVA - and more to
the point weigh a ton.  I'd shoot for something you can lift - more like
about 5kVA.

> So far, I have found that the
> biggest problem is the core -- I don't think it can just be a piece of
> barstock b/c it seems like it will saturate really easily -- is this
> right?  Also, eddy current and hysterysis (spelled wrong) are less in a
> laminated core, so I pulled this out of my shorts:  How about using many
> small metal "dowels" and coating them with a sealer of some sort (will
> polyurethane stick to metal??), then sticking them all together.  What
> you have now is a neat little bundle of rods - wrap the primary and
> secondary, then bend the whole mess around a garbage can to form a
> toroidal shaped tranny.  It seems like this should work.  Will it?
It's not too hard to get a big EI core - see if the power co have any dead
pigs you can have and use the core (or see if they've got any live pigs and
take them)

If you do go the mascohist route make friends with your local xfmr
manufacturer, it takes literally a tenth the time to wind on a proper lathe
with a traverse than by hand.
>
Happy Winding
Nick Field
> Any comments apprecited.
>
> Thanks,
>
> Ross
>
>
>