Re: The Best Pmimary Type Was: A few Q's from a beginner

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi Robert,

Thank you for the reply. If I understood correctly, the best primary for
your situation is the one with
the highest current and least trouble as used with the coils to power your
accelorator. I would agree for
that application and for maggy's. But not for what more than 90% of the
lists coils are used for (sparks
and arcs). Every coil has some point where coupling is too high and racing
sparks occur or where primary
to secondary arcing occurs. Any primary configuration can be adjusted to
cause or prevent this.
Obviously, adjusting to the highest current without these issues is ideal,
but there are other issues,
like sparks attacking the primary.

When all is said and done, a flat primary can be adjusted to produce high
induced current in the
secondary (barely tollerable) and will be physically further away from top
load sparks than other primary
configurations resulting in less primary attacks. In the large percent of 2
coil systems, I would have to
say flat primary's are ideal, less problematic, and can produce the same
sparklength in our typical
'sparking in the garage' applications. In other applications where high
coupling is tollerable and
primary attacks are not applicable, then helical primary's are the ticket
as long as arc-over and racing
sparks are prevented.

Take care,
Bart

Tesla list wrote:

> Original poster: "rheidlebaugh by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <rheidlebaugh-at-zialink-dot-com>
>
> Bart: My comments are based on trial and lots of error in using my verious
> TC coils to power my linier accelorator. No I dont have a drawer of computer
> models, just what works and what dosent. I like the solinoid because I get
> the most current delivered to my load. I can deliver power in three resonant
> modes, but that makes tuning a problem. Some times I must put pieces of PVC
> pipe inside my primaty to stop arcover to my secondary. I use spaced winding
> secondary, polyester coated with a 1 ohm resistor at ground to monitor
> current. My flat primary has only one usable mode of tuning and delivers
> about 60% as much current to my carona rectifiers using the same secondary.
> This gives no problems with arc over . My imverted cone primary gives nearly
> as much current out as my solinoid primary with the base of the primary
> about 1.5" above the base of my secondary with few problems. I have tried
> several different cone angles and 45o gives the best current out with the
> least trouble.  I have secondary coils of different angles that I use for
> routine use. My 30o secondary cone, solinoid primary, VTTC is my work horse
> because it takes up the least space on the shelf.-dot-compact..and I can run it
> all day long with out any change in conditions when I'm testing. I don't do
> any tests with spark length as a criteria. I guess that would depend on
> emitter/target shape and humidity more than any thing els. Not a testable
> varriable with any reproducable results you could depend on. When testing I
> try to have the least number of variables to contend with. That is why i use
> the same secondary to test primaries. same cap, same SG, same transformer,
> same "t" filter, same load. My flat primary is my standard to test
> secondaries because it gives the least problems with arc over, compact it is
> not. It is 26" diameter. My solinoid test primary is the same inductance,
> but is only 8" dia i.d. two layer coil.
>    John's comment that spark length is probibly not a noticable differance
> is most likely correct.
>     Thank you gentelmen for your responce, my opinion stands.
>    Robert  H
> > From: "Tesla list" <tesla-at-pupman-dot-com>
> > Date: Sat, 30 Mar 2002 18:06:22 -0700
> > To: tesla-at-pupman-dot-com
> > Subject: The Best Pmimary Type  Was: A few Q's from a beginner
> > Resent-From: tesla-at-pupman-dot-com
> > Resent-Date: Sat, 30 Mar 2002 18:23:10 -0700
> >
> > Original poster: "Barton B. Anderson by way of Terry Fritz
> > <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>
> >
> > Robert,
> >
> > I would say... the same thing John said. However, I suspect your comments
> > about
> > primary types has to do with either some tests you have run or models
> > you've run?
> > Kind of curious if the comments stem from a look at surge impedances for
> > primary
> > types or maybe flux convergence to a typical solenoid secondary? Obviously,
> > I'm
> > curious if you could elaborate a little more on the subject.
> >
> > Take care,
> > Bart
> >
> > Tesla list wrote:
> >
> >> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> > <FutureT-at-aol-dot-com>
> >>
> >> In a message dated 3/30/02 2:29:00 PM Eastern Standard Time,
> tesla-at-pupman-dot-com
> >> writes:
> >>
> >> Robert,
> >>
> >> I am not as confident as you are that the best form is a 45 degree
> >> form.  I also don't see anything difficult about building it.  I also
> >> would not say that a flat primary has less efficiency.  I also would
> >> not say that a solenoid coil has the best coupling or power transfer.
> >> I also would not say that solenoid coils have more racing sparks,
> >> and arc over problems.  Any of the primary shapes can be easily
> >> adjusted to give optimal coupling, and power transfer, without
> >> arc-over or racing sparks.
> >>
> >> It's true that a solenoid coil can give the tightest coupling,
> >> but tightest does not necessarily mean optimal.
> >>
> >> I've used a flat primary for a tube coil, and that worked fine too,
> >> and was quite efficient.
> >>
> >> Certain shapes may have less inductance for a given wire length,
> >> thereby increasing the losses, but the results on spark length
> >> will probably not be noticeable.
> >>
> >> Cheers,
> >> John
> >>
> >>>
> >>> Brad: the costruction of the primary is a trade-off. The best form is
a 45o
> >>> cone slightly above the base of the secondary. This is hard to
> > construct and
> >>> mount. A flat primary has the least coupeling problems and is easy to
> >>> construct, but has the least efficency. A solinoid primary has the best
> >>> coupeling and power transfer, but the most arc over and running arc
> >>> problems. It is the easiest to construct and most trouble. Tube TC
> > coils use
> >>> the solinoid coil primary because they nead the best coupeling to
oscilate.
> >>>
> >
> >
> >