Re: Ballast Inductor

[Megavolt121-at-aol-dot-com (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Mike
    With an NST powered system, you don't need ballasting. NST's have their 
own internal ballast int he form of shunts. thats why they only output 60 ma, 
30 ma, etc etc. Of course, if your like Ross, you'd dissect your nst, pull 
out 1/2 the shunts and hotrod you nst to run at 2-3 times the rating and call 
it a 1/2 nst.
-Alan


In a message dated 10/3/00 8:19:02 PM Pacific Daylight Time, tesla-at-pupman-dot-com 
writes:

<< Original poster: "M Fabs" <the_machin_shin-at-hotmail-dot-com> 
 
 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 >>