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Re: Power factor correction
Original poster: "David Rieben" <drieben@xxxxxxxxxxxxxxx>
Aaron, all,
This is is interesting. I wonder if others could share
additional insight regarding this? I, too, use a large
line filter with my setup, as I use the same power
control cabinet to drive my Jacob's ladder that I
power my Green Monster coil with. I use a 3-phase,
80 amp per leg, 440 volt rated line filter for my power
control cabinet setup and run the 2 "hot" legs
of the 240 volt input into 2 of the 3 phase legs of the
filter. I use this same power control cabinet to both
fire my Green Monster Tesla coil: http://dawntreader.net/hvgroup/david/gm.html
and my x-ray transformer powered Jacob's ladder. (sorry,
no pics of the JL uploaded yet). This webiste also needs
updating, since I have now consolidated the control panel
with the pole pig into a single 6 ft tall control panel that I
built out of an old computer server rack. It should give
a general idea of my particular setup, though. Like I said
previously, I fried or at least sent into a tailspin some
sensitive electronic equipment in my house with this coil
when I fired the coil too close to the house (or inside the
garage :^)) including my garage door opener, (and there
was no DIRECT spark contact with the opener control
box), in spite of all of my filtering, but I have never, to my
knowledge, damaged anything else in the house by firing
my JL with this same setup. Of course, I haven't tried
measuring for voltage spikes on the line while firing the JL
either. Since nothing has seemed amiss, I suppose I never
saw the need to.
David Rieben
----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Saturday, June 24, 2006 9:05 AM
Subject: Re: Power factor correction
Original poster: "J. Aaron Holmes" <jaholmes@xxxxxxxxxxxxxxxxxx>
I killed a PC power supply (not the whole PC,
fortunately!) running my 25kVA pig as a Jacob's
ladder, sans line filter. I was doing about 15kVA at
the time, IIRC. Since getting a large 75A line
filter, I have observed that the spiking is suppressed
substantially, though. Whenever the arc reached the
top of the ladder and broke, I'd get a 600V (peak)
spike. Nasty!!! I was ballasting with a water
resistor at the time. Not sure, but inductive
ballasting seems likely to make the problem worse. I
did not notice any significant reduction in the spikes
when I used my smaller 15kVA pig, either.
The reason I'd call really big spikes like this
"worse" than RF from a TC is that, to me, they seem
more apt to compromise the insulation in your house
wiring, setting the stage for badness like fires, and
other things that would be really difficult and
expensive to diagnose and fix. Others may have had
really bad experience with RF from TCs...I guess I
*should* have said this: Big Jacob's ladders are
quite able to fry stuff in your house, just like TCs
with no filter. They're not "safe" in any way (to you
*OR* your supply). A lot of people wire up big
Jacob's ladders on a whim. I was one. For posterity:
I recommend a bit more caution these days :-)
Regards
Aaron, N7OE
--- Tesla list <tesla@xxxxxxxxxx> wrote:
> Original poster: "David Rieben"
> <drieben@xxxxxxxxxxxxxxx>
>
> Aaron,
>
> I hope the moderator will allow a little bit of
> latitude here since
> we are talking about Jacob's ladders but this post
> will also ad-
> dress Tesla coils and many coilers build JLs as well
> during the
> "learning curve" toward building a coil. That
> flickr.com JL photo is from
> Clint Dickey, who was a list member at one time, but
> not sure he
> still subscribes. He resides about 55 miles from me
> here in the
> Memphis area and I helped him put a lot of his stuff
> together. I
> assume his "15 kVA" nomenclature is referring to the
> rating of that
> pole pig, which it was, and not to what he was
> actually pul-
> ling from the wall socket.
>
> BTW, I've never experienced any of the "voltage
> spike" problems
> caused by the arc "snapping" at the bottom of the
> rails when it
> starts its "climb" that you mention, although I'm
> sure that under the
> right or wrong circumstances, actually, this could
> be a problem.
> I wouldn't agree that it could be more of a problem
> than
> with a large Tesla coil that draws similar power
> levels, though. I've done
> quite a bit of damage to other sensitive electrical
> components in
> my house in the past from firing a large Tesla coil
> but have never
> damaged anything from firing a JL, even a very large
> and powerful
> one. Maybe the control panel ballasting that I use
> to control the
> input to my 125 kVp, 500 mA x-ray transformer helps
> to suppress
> any of the transient nasties that could try to feed
> back into the house
> wiring by the snap of the arc starting? However, the
> ballasting didn't stop
> damaging kickbacks from the large coil when I did
> something wrong,
> as I use the same ballasting control panel for my
> large Tesla coil that
> I use for the x-ray transformer powered JL.
>
> David Rieben