Re: [TCML] Pig Ballasting...

[Joe Mastroianni <joe@xxxxxxxxxxxxxx>]

I did what you are suggesting, only I used 500' of 10GA.   I made a spool out of 2" PVC with some flat polycarbonate scraps glued on the ends (but not blocking the interior hole of the PVC) to hold on the wire.   The spool is about 18" long. Took quite a bit of muscle to wind.

I experimented with different configurations for the core.  I had a couple 8' rods of aluminum and steel that I cut up into 2" sections.  Generally speaking the forces want to pull the rods into the core, not visa versa.  If you do the math you see it doesn't matter which way the current is flowing in the solenoid, so it doesn't matter that it's AC, then, either.

The real issue you face is heating of the core materials.  My pig is only rated at 5KVA so I rarely pushed it above 10.  And in any case at 6kVA I was getting ground strikes so I didn't feel the need for much more.  I was measuring the input V and I to the variac, as well as the output, and shoving things into and out of the ballast core to get reasonable levels.   But those interior rods got really hot, probably because I just threw them in there, but also probably because the eddies in some of the materials were severe.

And the core would stay hot for a long time.  I never melted through the PVC, but I was close.   I'm not sure the best way to cool it down as I switched to DR coils and didn't experiment much more with that.

Cheers,
Joe


On Oct 26, 2012, at 10:27 AM, Travis Tabbal wrote:

> I've seen a number of options in the archive. I was just wanting to get
> input on what I wanted to try to make sure I'm not off the deep end
> somewhere before I mess with it. Piggy is 14.4kV 10kVA.
> 
> I was thinking of getting a 500' spool of AWG12 THHN wire from Home Depot
> or similar and winding it around a 2" PVC or similar tube, about 1.5ft
> winding length. Then getting some ferrous wire from there as well, perhaps
> something like the little yard flags or something from the fencing
> department for the core. I'd pot the core material inside a smaller tube,
> even just as a mandrel, with epoxy or similar (Bondo?). With a threaded rod
> at the top of the potting for adjustment. Then just build a frame to hold
> it together while in operation, seems like the cycling of the magnetic
> field from the 60Hz AC might want to push the core out otherwise?

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