[Prev][Next][Index][Thread]
Re: New System, was "Real Data--
In a message dated 96-11-16 03:14:31 EST, you write:
<<
Hi Ed:
Right now I am trying to sort through several alternatives associated
with my winter project. Yes, it is a two coil system and I have a 10
KVA 14,400 VAC pole pig, welder ballast and Superior 1256D variable
transformer in the supply. Last night I decided to change the secondary
to a 56" length with the 15.25" form diameter in order to get a bit
lower in frequency. This results in a resonance of about 106 Khz
without a toroid. My curiosity at this point centers about picking the
optimum capacitor size, with maximum spark being the goal. I originally
thought a .1 mfd cap would be about in the correct range, but alot
depends on how far the secondary resonance will drop with a proper
toroid, if an ideal L/C ratio is a target. I'm still not clear on what
the proper L/C ratio might be. My 8" diameter by 28" long coil had a
221 Khz resonance and with the 48" toroid it dropped to a measured 94
Khz. If I could expect the 106 Khz resonance of the new secondary to
drop to around 50-55 Khz with a big toroid, I would have a primary
needing about 100 uh with the .1 mfd cap. O.K., I guess I could just
slap a random choice cap size in there and hope for the best, but
another option makes more sense to me. That option is, we have a
tremendous amount of experience in this group and I sure don't mind
listening for a few weeks and filtering out the stuff that will help me
get a notch closer to the best I can personally do (The real story is, I
sure don't want to spend $450-$600 on a cap that isn't quite right!).
My last primary had 15 turns so I have no problem with a similar design
here. I will use 5/8" thin wall copper refrigeration tube, if they make
it in that size! Haven't checked yet.
I am planning on using the 12" diameter flexible aluminum air duct for
the toroid perimeter. I used the same type of stuff but in 6" or 8" on
the other coil and was happy with the results. I figure on a 60"
diameter for this one. Yea, I guess I'll need lots of power to get it
to break out. I have room for a few more breakers downstairs and the
next one will be a 100 amp line out to the Tesla area, or that spot my
wife calls the drive way. Silly, she thinks she will be able to use the
garage next year!
I got a couple of parts made today for my winding system for the
secondary. I should have the PVC form mounted up and getting close to
winding this next week. I am getting a gear reduction drive unit
coupled to a shaft and support system to hold the form while winding and
then I'll coat it with the Behr Super Build 50 polyurethane varnish--I
really love that stuff! I will take photo's so that when it's 10 below
zero here I can have something to look at and wait for spring. As
always, I appreciate any ideas and comments. Thanks in advance!
Chuck Curran
Cedarburg, WI >>
Chuck,
This sounds like a super system. It should perform very well. I agree about
the capacitor, for that kind of money, you don't want to be too hasty.
I also am relegated to operating only outside on the driveway - having
outgrew the basement and the garage. I sure wish I had a nice large heated
building to set all this up in. I made good progress when I had the coil set
up in the basement. Every night after work I could experiment and leave
everything set up for the next day. Now it is a big job to get it all set
up outside to run it - depending on the weather of course.
Ed Sonderman Spokane, WA