RE: Geek Pig! :)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "David Dean by way of Terry Fritz <twftesla-at-uswest-dot-net>" <deano-at-corridor-dot-net>

Hi

> >
> >The thing is that just because a transformer is rated 5KVA
> (mine) or 10KVA
> >(yours) does not mean that it has to deliver that much power.
>
> It does when you don't have a variac :)
>
Power delivered equals power that can be pumped into the system which is
determined by the size of the cap and the BPS plus the losses, most of which
are to be found in the gap. Resistive ballast works great for limiting the
total power that can be delivered. An old electric furnace with four 5KW
heat strips in it works great. That is what I used to start out with. A 5KW
heat strip for 240V operation is about 12.5 Ohms. They can be hooked in
series or parallel or any combination to give a range of resistance from
around 3 Ohms to 50 Ohms. Use the blower that is in the furnace to keep the
heaters cool. Not a bad deal in the winter. When you get things working well
then you can switch over to inductive ballast and give it the juice. Just
remember that if you are using a sync. rotary that the firing angle will
change a few degrees when going from resistive to inductive ballast. Also
the firing angle changes with any change to the cap or ballast with a SRSG.


> >I have no Ideas about that. I did run for the first year I had the pig
> >without a variac with no problems. It is just a bit wild to tune
> with only
> >full power available.
>
> Yeah, we're not looking foreward to that.
>
>
> > >
>
>
>
> >By cage you mean Faraday cage?
>
> Yes, we have a sealed room (with ventillation) that we run in.
> It's a large
> paint booth at one of our local sponsors'.
>
> Are you saying that you connect the base of
> >the secondary to the same ground as the cage itself?
>
>
> Yes, right to the wall.
>

In the case that you are in the room, the walls etc. should be at the same
potential as the base of the secondary. So for your case, you are doing it
right. The last thing you want to expose yourself to is a difference in
potential. It would not matter if the whole thing is floating at 100s of
kilovolts above the "absolute" ground potential, as long as everything
inside the room is at the same potential. (with exception of course to the
"business" end, primary circuit, etc.)