Re: New tranny arrived today, need ballast advice

• To: tesla-at-pupman-dot-com
• Subject: Re: New tranny arrived today, need ballast advice
• From: FutureT-at-aol-dot-com (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
• Date: Tue, 22 Feb 2000 11:55:06 -0700
• Approved: twftesla-at-uswest-dot-net
• Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

In a message dated 00-02-22 11:23:04 EST, you write:

<< Original Poster: "Adam" <adamsmith-at-mediaone-dot-net> 
 
 
> My new GE transformer arrived today, and I'd like to get some suggestions on
> how to current-limit it for 120V/20A service, and how many VA I can expect
> to use this at.  The transformer is the following type:
 
>    General Electric
 >    JVW-5 "Hi-Bute 60"
>    1500 V.A. (30 deg rise)
>    120:1 (14,400-to-120)
 
> Anybody use this same model? I know i've seen similar on some of the webring
> sites.  If that's your site, what are you ballasting it with? :-)

Adam,

I use the hi-Butes, same specs.  Richard Hull used to run them
up to triple their ratings.  Nice xfrmers, but as dangerous as a pole pig.
 
> Up to this point, I have only run my coils with banks of NSTs, so I really
> don't know the first thing about practical pig/pot ballasting solutions.
> I've read everything I can find in the pupman archives relating to
> ballasting and potential transformers, but I still have no concrete examples
> to go by.  What I have to work with are some NSTs, a pair of MOTs, and some
> old hotplates I've gotten from peoples' trash (the kind with a flat spiral
> heating coil--good power resistors?).

You can use a welder, a variac, or a homemade ballast.  I'm using the
homemade ballast now.  It's about 300 turns of #12 wire on a 3" by
19" pvc form, with straight transformer iron laminations tossed into
the center.  I once tried the variac method but it drew double the
power.  I think that was because I'm using reso-charging which
caused saturation of the core.  If you use a higher break-rate, this
probably wouldn't be such a problem because the primary voltage
will never go that high.   You could try using MOT's as ballast, but I've
never tried it.

Cheers,
John Freau
-
 
> My last question is: how many V.A. can I really use this thing at, for short
> (under 30 second) runs.  In other words, ignoring the heat factor associated
> with continuous operation, how much current can I really safely extract from
> this tranny?
 
> Thanks a bunch,
 
> Adam >>

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