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RE: Converting to "Pig Power"
Original poster: "Randy & Lori" <rburney6-at-comcast-dot-net>
Thanks Bart. Next weekend just happens to be the only listed Hamfest for
the year in Atlanta; I'll try and mosey that way Friday and stay with some
relatives. If I can get the wife to let me have a quantity of cash! As
far as she is concerned "COIL" is fast becoming a four letter word just
like "BIKE", "BOAT".... Thanks again
Randy
-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Friday, March 12, 2004 11:33 PM
To: tesla-at-pupman-dot-com
Subject: Re: Converting to "Pig Power"
Original poster: Bart Anderson <classi6-at-classictesla-dot-com>
Hi Randy,
From your specs, it sounds like a 20A General Radio Co. variac (plate on
bottom where the wiper contacts winding?). If your looking at over 20A on
the pig (probable), you'll have a hard time using it. I have a couple of
these and even tried cutting the core on one of them. It went into
over-saturation almost immediately (was using 10kva pig at the time). I
just went hunting for a larger variac and found the 30A type of which I cut
the core (that worked out ok). If I were you, I wouldn't waste my time
cutting the core on this small variac. You wouldn't gain much. Better off
just going in search of a larger variac or alternate source of inductive
ballasting.
Take care,
Bart
Tesla list wrote:
>Original poster: "Randy & Lori" <rburney6-at-comcast-dot-net>
>Bart,
>
>The variac doughnut measures 8.25" across, 2.18" across short section,
>2.7" tall, and the wire size is 15 gauge. There are 7 terminals. The gauge
>seems kind of small now that I have measured it. In fact it seems real small!
>
>If I were to cut the torrid and re-wrapped it with 8 gauge, does anyone
>know what kind of inductance I could expect? I'm not crazy about cutting
>it, but I'm not opposed to it either.
>
>Randy
>
>-----Original Message-----
>From: Tesla list [mailto:tesla-at-pupman-dot-com]
>Sent: Thursday, March 11, 2004 9:32 AM
>To: tesla-at-pupman-dot-com
>Subject: Re: Converting to "Pig Power"
>
>Original poster: Bart Anderson <classi6-at-classictesla-dot-com>
>
>Randy, Ed,
>
>Tesla list wrote:
>
> >Original poster: "Randy & Lori" <rburney6-at-comcast-dot-net>
> >Ed, and list
> >
> >The reason given by Dr. Resonance for grounding one of the HV terminals
> >(and I liked the idea) was to put the bottom of the secondary and the
> >center of the primary at the same potential. Also this configuration would
> >leave me with only one HV line to run.
>
>Exactly. That's how I run these days. I have a 2-bushing pig and simply tie
>1 bushing to RF and run the other to the coil. The inside of the primary is
>at the same potential as the bottom of the secondary (RF ground). Without
>that, there is "some" potential difference between the two coils. I'm not
>sure there is a great deal of difference that might force pri to sec
>arcing, but I liked the idea of knowing the beginning of the inner primary
>is at RF ground. David Rieben is the one that turned me on to this about 2
>years ago. I also like less mess with cables.
>
> >My coil is currently tuned, and unless someone had a reason to not just
> >shoot the power to it; then that was the plan.
>
>Agree with Ed here. It is certainly better to control the both voltage and
>current then to just throw a switch. Hopefully, you can find a suitable
>variac for the purpose.
>
> >120 instead of 240 first certainly. Don't get me wrong, I would very much
> >like to ramp it up slow, but I'm not sure that my Variac is quite large
> >enough to deal with 30+ amps.
>
>I don't remember if you described your ballasting scheme (please forgive if
>you already posted it), but with an adjustable inductance, you can limit
>the current down to well below 30+ amps.
>
> >If anyone can tell me how to figure out the current ratting of my variac,
> >I would appreciate it(it came without an ID plate). I like the idea of
> >bringing it back down slow as well, rather than just opening the contacts
> >on the relay.
>
>Maybe you can post some winding dimensions, wire size, core dimensions,
>etc.. and we can probably tell you the current rating. BTW, I'm also one of
>those that cut the core in a perfectly good Powerstat 28A variac which I
>use for a ballast. Why? Simply because I only had this variac available at
>the time and knew I would be running well over from time to time. If this
>variac would have been in the 40 or 50 A range, I would not have cut it. I
>also use an identical variac for the voltage control (this one of course is
>not cut - just a normal variac in normal voltage adjusting application).
>
>Take care,
>Bart
>
>
>
> >So far I have:
> >2 get more caps
> >2 put a variac on it
> >1 filter ok
> >1 get a bigger filter
> >
> >Anybody else have any suggestions? Like I said, it would be kind of stupid
> >of me not to ask.
> >
> >Randy
> >-----Original Message-----
> >From: Tesla list [mailto:tesla-at-pupman-dot-com]
> >Sent: Wednesday, March 10, 2004 7:07 PM
> >To: tesla-at-pupman-dot-com
> >Subject: Re: Converting to "Pig Power"
> >
> >Original poster: Esondrmn-at-aol-dot-com
> >
> >In a message dated 3/9/04 11:55:40 AM Pacific Standard Time,
> >tesla-at-pupman-dot-com writes:
> >
> >
> > >Original poster: "Randy & Lori" <rburney6-at-comcast-dot-net>
> > >
> > >The pig is due in this week(14.4 10 KVA), and being as intelligent as
> I am,
> > >I thought I would run my setup past the list. The secondary is
> 6.25âàX
X
> > >24.5âàwith 26 gauge. The Tank cap is 2 strings of 10
942Cs for a
a
> > total of
> > >.03 uF. I am currently tapped on the primary at about 12 turns (out of
> > >23). Iâm not sure just what the modified 15/30 is putting out
> (half the
>e
> >e
> > >shunts removed). The gap is currently a sucker gap (vacuum through
> ÃþâÃÂ
Â
>
> > >copper pipe).
> > >
> > >I plan to ground one HV terminal of the pig to the case, center of the
> > >primary, bottom of the secondary and of course earth ground, as
> recommended
> > >by Dr. Resonance. I have a 30 Amp line filter, the 500â roll
of Home
e
>e
> >e
> > >Depot special for some current limiting.
> > >
> > >My concerns: If the 500â roll is to hold me to about 30
Amps, is
> the line
>e
> >e
> > >filter too small?
> > >Will the sucker gap give any kind of acceptable performance (or will it
> > >just âPower ArcâÃÂ)?
)?
>)?
> >)?
> > >Do I need more capacitors (to spread the wealth)?
> > >I read (one place only) that a pig doesnât need any PFC???
?
>?
> >?
> > >
> > >Iâm not asking for someone to do all of my math for me; just
give
> some
>e
> >e
> > >suggestions from your personal experience. I just feel that throwing
power
> > >to a pig for the fist time without running my setup past the list
would be
> > >a little stupid and arrogant on my part.
> > >
> > >Randy
> >
> >
> >Randy,
> >
> >I have a two bushing 5 kva pole transformer and just leave both bushings
> >and the primary floating - i.e. not connected to ground. Why do you want
> >to ground one HV output and the primary?
> >
> >Are you really going to just throw full power to the coil? Or do you have
> >a variac to ramp the voltage up nice and slow? If you don't have a variac,
> >I would at least only apply one half power to the pig. Like using 120
> >volts in instead of 220. You want to make sure it is all going to work
> >before just slamming full power to it. You could also add some resistive
> >ballast in series with the pig primary, like oven heating elements,
> >electric heaters, etc.
> >
> >Will two strings of mmc caps in parallel be enough to handle the high tank
> >currents? My opinion is no. I think you need four strings in
> >parallel. Someone more knowledgeable than I should provide input on this.
> >
> >I am also not real familiar with the sucker gap. I could not get a copper
> >segment pipe gap to quench and had to go to a rotary.
> >
> >I use a 30 amp line filter and regularly run 30 to 35 amps through it.
> >
> >Ed Sonderman
> >
> >
> >
>
>
>
>