Re: Ballast Inductor

["M Fabs" <the_machin_shin-at-hotmail-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Just two more questions about my ballast, and then I'll leave you alone 
(well, not really, but anyway):

I was hoping to check my understanding of the saturation you mentioned.  
That is when the iron is being subjected to just as much magnetic flux as it 
can handle, and any flux beyond that amount just ignores the iron and moves 
through the air around it, right?  Thus you lose the prime benefit of the 
iron core (more inductance in the same space as an air core). So there is a 
practical limit to how much current can travel through an inductor, based on 
the cross section of the core.  I think that explains my understanding 
fairly well, does it make sense?  For approximately 20-30 amps peak, would 
the 2" I.D. conduit hold enough iron in the 1/8" welding rods to not 
saturate? Or should I rebuild a 4" or maybe 6" version?

I should have mentioned this next piece in my first post, but here it is:  
the welding rods are each copper plated. They consist of a core of mild 
welding steel, with a copper coating.  Is this a bad thing?  I think 
somebody else asked this question before, but I am doubting my memory of the 
answer.  I polyurethaned the individual rods before bundling them up and 
then coated them again to lock them together, so there is no continuity 
between adjacent rods.  I am still concerned about the shorted turn 
potential with these copper coatings.  Of course the iron itself would make 
a shorted turn too (hence the need to make transformers with thin 
laminations...), so maybe I will be OK.

Any thoughts would be welcomed!!

BTW:  I don't have a pole pig, or even a working coil yet, but I do have a 
stack of NST's, NST filter parts, a primary coil wound on a lexan form, and 
more recently a 4" sch 40 secondary wound with #22 wire + polyurethane, a 
whole bunch of DigiKey AC caps (PFC), and a whole bunch of DigiKey/Panasonic 
pulse caps soldered to perfboard (MMC).

I'm playing with this ballast because #10 is easy to wind, and I would like 
to have complete understanding of large inductors + high voltage (120,240, 
etc) + high current before I venture down the pole pig way (well into the 
future).

Enough run on sentences, Thanks for your help.
Mike
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