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RE: New Files at www.teslacoil-dot-com
Original poster: "sundog by way of Terry Fritz <twftesla-at-qwest-dot-net>" <sundog-at-timeship-dot-net>
Hi Jeff, All,
I've noticed a *big* transition from the modest 2-5kW range, up to the
10kW+ range in my own coiling efforts. Space and neighbors prevents me
from running really big coils a lot, so my experience is a tad limited in
that respect, but here's what I've learned -
Primary conductor is a big concern. Small diameter tubing just gets
really hot.
Tank caps take a horrendous beating at higher power levels, for several
reasons noted below.
Secondary coils become expensive because of the length and size of wire
needed. The weigh also goes up astronomically with larger coils. (12"
green PVC weighs a ton itself, then slap wire, endcaps, poly, etc on
there.) Usually you use less turns on the larger coils, dropping your
primary turns, and *really* dropping the primary turns when you use a large
tank capacitor. This means higher RMS current on the primary and caps, and
the base of the secondary.
The secondary ground connection must be good. I've had significant
heating in my base's RF ground, because of poor connection (crimped ring
onto the magnet wire - soldering helped considerably with that.
The control system must be more heavily protected. Pole-pigs tend to
pass more trash through to the primary side via strikes to the primary and
HV feed lines. I've seen this on my own coils and on my buddy's coils.
Room. Big coil=big noise + bigger sparks. Whereas a 1kvA coil may
give you a nasty jolt if it reaches out and touches you with a streamer, a
big coil can hurt you pretty badly. Even worse when you fall down and land
on something dangerous (end of a ground rod, concrete, etc).
Power. 10kvA is 240v at 42A. That's a lot of juice, and your normal
dryer outlet probably won't be too happy about providing that. A dedicated
run of heavy 3 conductor wire on it's own breaker is a definite plus.
Twist-lock connectors are also worth their weight in gold here.
The control system... The variacs, ballast, and EMI filters (you *are
using filters, right? :) take a beating. My ballast will thump and buzz
when running LTR at 7kva (200nf tank cap), and current spikes on the pig
are considerable, but controllable. (performance is outstanding, btw)
And lastly, cost. The cost of a NST system is pretty mild. The cost of
a pig system can get prohibitive. It's not just the pig, it's also the
caps, control system.
However, it seems that once you get over 300mA of charging current at
*any* voltage, you start running into problems where the RSG must be of
high quality, and tank cap current capability becomes increasingly
important. Ah, the price we pay for long sparks....
Hope it helps!
Shad
At 10:15 AM 11/4/2002, you wrote:
>Original poster: "Jeff W. Parisse by way of Terry Fritz
><twftesla-at-qwest-dot-net>" <jparisse-at-teslacoil-dot-com>
>
>Terry & All,
>
>The poles were set 10' away from the coil and were 45 degrees apart so
>your guess was pretty much right on the money. The discharge points were
>also set 45 degrees apart to match the poles. The video camera was off
>to one side because the still camera was set dead center (see the .jpg).
>I don't recall the exact number of turns but generally we use about half
>the number of turns of smaller (<8kVA) coils (NST, MOT, OBIT, PT). Same
>with wire; less resistance is better so we go for "bigger", however, the
>same doesn't (may not) hold true for smaller coils.
>
>I believe that there is a physical leap at 10kVA... That is, many of the
>"rules of thumb" change dramatically at or near that power level and
>many design factors (overall system Q, RF grounding needs, insulation
>factor, coupling, tuning, etc...) "change" in a non-linear way (i.e.
>things stop scaling up like one expects them to). This is just a
>personal observation I have "noted" in the last six or seven years.
>Maybe others who have make the 10kVA transition can comment?...
>
>Jeff
>
>
>
>-----Original Message-----
>From: Tesla list [mailto:tesla-at-pupman-dot-com]
>Sent: Sunday, November 03, 2002 10:21 AM
>To: tesla-at-pupman-dot-com
>Subject: Re: New Files at www.teslacoil-dot-com
>
>
>Original poster: "Terry Blake by way of Terry Fritz
><twftesla-at-qwest-dot-net>" <tb3-at-att-dot-net>
>
>That is some awesome teslacoil action. Now I need a 48x12 toroid. What
>is the secondary wire gauge and number of turns? Is it 60" high (1:3)?
>
>It looks like about 2.5 toroid widths to the poles in the photo. That
>would be about 10 feet. But since the poles are going at an angle (one
>close to the camera and one far), I guess that the distance is bit over
>12 feet. Is that what you figure Jeff?
>
>Terry Blake
>Getting cooler in Chicago.
>
>----- Original Message -----
>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: <tesla-at-pupman-dot-com>
>Sent: Saturday, November 02, 2002 6:53 PM
>Subject: New Files at www.teslacoil-dot-com
>
>
> > Original poster: "Jeff W. Parisse by way of Terry Fritz
><twftesla-at-qwest-dot-net>" <jparisse-at-teslacoil-dot-com> > > TCML, > > I've
>posted two files from Halloween on my driveway on the kVA Effects Web >
>site. > >
><http://www.teslacoil-dot-com/files/kva_halloween_2002.jpg>www.teslacoil-dot-com
>/fil
>es/kva_halloween_2002.jpg
> > - a 231k photo by Ross Overstreet
> >
><http://www.teslacoil-dot-com/files/kva_halloween_2002.mpg>www.teslacoil-dot-com
>/fil
>es/kva_halloween_2002.mpg
> > a 7.5 mb video of two runs (15 sec & 20 sec)
> >
> > The coil is the Model 9J. It was turned down so as to run off the
>240v, > 100A feed to the house. > The meters showed about 18kVA.
>Specs: 20" form -at- 1:3, .2uf cap, primary > tapped at three turns,
>48x12 toroid. > > Enjoy! > > Jeff W. Parisse > Director, kVA
>Effects > <http://www.teslacoil-dot-com/>www.teslacoil-dot-com
> > 310-748-5893
> >
> >
> >
>
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Shad (Sundog)
G-5 #1203
"Ever stop to think, and forget to start again?"
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