Re: Cheap parts for high-power resistive ballast (for pole transformer). (fwd)

["High Voltage list" <hvlist@xxxxxxxxxx>]

Original poster: <sroys@xxxxxxxxxxxxxxxxx>



---------- Forwarded message ----------
Date: Thu, 2 Jun 2005 20:43:44 -0700 (PDT)
From: J. Aaron Holmes <jaholmes@xxxxxxxxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Cheap parts for high-power resistive ballast (for pole
    transformer). (fwd)

No contest.  But I acquired twelve 5kW water heater
elements and ten 40A relays for a total of about
$45.00 on eBay.  At this point, it'll be far cheaper
and simpler to get to 50kVA input power this way than
trying to do so inductively.  Optimum efficiency is
definitely a non-goal for this Jacob's ladder project
;-)  I'll get an arc welder for my TC, as soon as I
find one locally for cheap.  Where I am, used pigs are
easier to come by than used welders! :D

--- High Voltage list <hvlist@xxxxxxxxxx> wrote:

> Original poster: <sroys@xxxxxxxxxxxxxxxxx>
> 
> 
> 
> ---------- Forwarded message ----------
> Date: Thu, 2 Jun 2005 12:53:34 -0700
> From: Dr. Resonance <resonance@xxxxxxxxxx>
> To: High Voltage list <hvlist@xxxxxxxxxx>
> Subject: Re: Cheap parts for high-power resistive
> ballast (for pole
>     transformer). (fwd)
> 
> 
> 
> For pole xmfr systems it's best to use an inductive
> external ballast.  An 
> airgap of 1/16th inch is filled with a tight fitting
> piece of plastic and 
> epoxied in place.  The gap is cut with a band saw.
> 
> Dr. Resonance
> >
> >
> > ---------- Forwarded message ----------
> > Date: Thu, 2 Jun 2005 08:26:40 -0700 (PDT)
> > From: J. Aaron Holmes
> <jaholmes@xxxxxxxxxxxxxxxxxx>
> > To: High Voltage list <hvlist@xxxxxxxxxx>
> > Subject: RE: Cheap parts for high-power resistive
> ballast (for pole
> >    transformer).
> >
> > (this thread is getting long...oh well, the list
> is
> > pretty quiet, too)
> >
> > Okee dokey, I've got my new transformers.  Yes,
> > there's an "s" on the end there; I picked up two.
> > When I got down to the salvage yard and saw how
> big
> > and heavy the 50kVA units were, I opted for two
> 25kVA
> > units instead.  They'll do the same job but can
> > actually be moved by a human :)  These 25kVA's are
> > actually smaller (the cans, that is) than my old
> > 15kVA!  They're also about 20 years younger, which
> > probably explains it.
> >
> > Anyway, my intent when I picked up two was to run
> them
> > in parallel (or series for nearly 30kV--another
> bonus
> > to having two instead of one), but then I had
> another
> > thought:  Several people have mentioned using
> > isolation transformers together with heater
> elements
> > to create a sort of hybrid resistive/inductive
> > ballast.  That is, they talk about putting the
> > elements in series with one side of the isolation
> > transformer and the pig in series with the other
> side.
> > Does this really offer any advantages?  Maybe for
> > Telsa coil operation it could improve the rise
> time
> > after the cap discharges...I suppose I can
> visualize
> > that...but for a Jacob's ladder?  It's just a
> > continuous short circuit, so I don't see how this
> > isolation transformer arrangement accomplishes
> > anything.  But I thought I'd ask.  Perhaps I could
> use
> > the two low-voltage windings of one of the
> > transformers kind of like an isolation
> transformer,
> > with one winding in series with the heater
> elements
> > and the other in series with the other pig.  It
> might
> > work :)
> >
> > Regards,
> > Aaron, N7OE
> >
> >
> >
> > 
> 
> 
> 
>