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

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

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.
>>> 
> 
> 
>