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Re: to Bert Hickman
From: DR.RESONANCE[SMTP:DR.RESONANCE-at-next-wave-dot-net]
Sent: Saturday, July 26, 1997 4:04 PM
To: Tesla List
Subject: Re: to Bert Hickman
To Bert, et al:
We use a 40 mH inductor with a 0.8 Oh.mn 10 kw series resistor with most
our pole pig units. The small resistance really helps during those sharp
peak saturation points and makes the coil run very smooth overall. We use
a 12 ft. long piece of monel resistance element coiled up into a compact 9
in. long x 2 in. dia. size. Our 40 mH inductors we manufacture using 130
turns #10 AWG on special laser cut C-core units. Size is 10" x 6" x 6"
overall. Runs fine at up to 20 kva then we use #6 wire and a much larger
core cross section.
Hope this information is of assistance.
DR.RESONANCE-at-next-wave-dot-net
----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: 'Tesla List' <tesla-at-poodle.pupman-dot-com>
> Subject: Re: to Bert Hickman
> Date: Saturday,July 26,1997 10:01 AM
>
>
> From: Bert Hickman[SMTP:bert.hickman-at-aquila-dot-com]
> Reply To: bert.hickman-at-aquila-dot-com
> Sent: Saturday, July 26, 1997 9:58 AM
> To: Tesla List
> Subject: Re: to Bert Hickman
>
> Tesla List wrote:
> >
> > From: Rodney Stapivic[SMTP:rstapivic-at-sprynet-dot-com]
> > Reply To: rstapivic-at-sprynet-dot-com
> > Sent: Thursday, July 24, 1997 8:28 PM
> > To: tesla
> > Subject: to Bert Hickman
> >
> > That is very true, you would definitely draw 3x more current than
rated.
> > I want to thank everybody for their inputs. Anyway have you priced what
it
> > would cost to construct a .19 Henries ballast? You sound like you're
in
> > the same boat I'm in...no arc welder and trying to do this project on a
low
> > budget. Let me know what you find out and I'll try to look into the
> > inductive ballast method myself.
> >
> > Thank you
> > Rodney
>
> Rodney,
>
> You may have confused me with Rodney Davies who also responded to your
> earlier post. I have a 225A arc welder and also a big 7 KVA tappable
> ballast I picked up at a junkyard for inductive ballasting on the pig.
> Others on this list have made their own inductive ballasts by using
> heavy gauge (#6 or 8 AWG THHN or similar housewire) wound around a 2 or
> 3 foot length of 3-4" PVC with a movable core made from transformer
> laminations or even welding rods! Inductive ballasting runs much more
> efficiently and delivers much better coil performance than simple
> resistive ballasting. The best overall solution appears to be a
> combination of both.
>
> I'd recommend scanning the local want-ads and scouting the junk yards
> for old welders or inductive reactors. You can usually get these for
> about the average of the going rate for the copper and iron - my big
> reactor ran about $20, and weighs over 54 pounds. The welder was more
> ($75.00) since it worked, and I got it through a want-ad in the local
> Trading Times newspaper.
>
> If you decide to wind your own, you'll still need to obtain the copper
> wire from somewhere, and it'll take a fair amount of fairly heavy gauge
> wire to do it. Simple THHN Housewire is not very expensive, and you can
> often find it very inexpensively at junkyards. You'll probably need at
> least 20-30 pounds worth. Make sure to bring out taps periodically, or
> have a method to vary how much iron is in the solenoid. Perhaps those
> who've actually wound their own can give you some more pointers.
>
> BTW, 0.19 Henries, or 190 MilliHenries, sounds much too large - the
> ballast inductance should be in the range of 3-5 mH (for max current) to
> 20-25 mH (minimum current) if you're running off 60 Hz and a 240 V
> source. However, this is _good_ news, since it significantly reduces the
> size of the inductive ballast you'll need. In any regard, chokes capable
> of handing 50+ amps tend to get quite large and heavy!
>
> Safe ballasting to you!
>
> -- Bert --
>
>