Re: Desktop Bipolar Coil

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

Original poster: "Steven Ward by way of Terry Fritz <teslalist-at-qwest-dot-net>" <srward16-at-hotmail-dot-com>

Some comments of my own on this 'discussion':


>Generally the goal of a coiler is long sparks.

Since large TCs dont have any practical uses, i would say that is the only 
design goal.  Most of us could care less to know EXACTLY how much power is 
being burned up and how much is in the sparks.  It seems that spark lenght 
and intensity are the most wanted characteristics, not really how much 
power is radiated or anything like that.

  It's possible for a
>coil
>to more efficient in the true sense of coil effiency, yet give shorter sparks.
>For example, one may have a coil that uses 1kW and gives a
>30" controlled spark length, and a 42" maximum spark length.
>Another coil may use 1kW and give 33" controlled spark length,
>but give only 40" maximum spark length.  Most folks would rather
>have the coil that gives longer max sparks, even though it's less efficient
>in the true sense.  These kinds of situations may possibly occur due
>to certain toroid sizes, breakrates, or other factors.

Seems to be a touchy area as to what is considered "efficient".




>>Single sparks are not being considered here as coilers seldom use this
>>method of comparing Tesla coils. Single sparks present a different problem
>>compared to multiple sparks. When multiple sparks are used the problem is
>>trying to find how much of the input TC watt seconds belongs to that special
>>extra long random spark. It does not appear that this will be possible until
>>new methods of instrumentation are devised.

It seems to me that an average is more important than finding those few 
situations where the spark does (at random) reach extra far.  But really, 
how can we say that this is completely related to the watt/second input?
For example, wind will reduce spark lenght.  Who is to say that there was 
more power processed when the spark does grow extra long?  Maybe just the 
fact that there are different gasses in the air, and the atmosphere in 
general around a tesla coil is ever changing, that produces those few extra 
long sparks.  So maybe it is safe to say that in extreme and non extreme 
spark outputs, the power is still consistent?

>>Finding an average length spark over a certain period of time would be
>>useful if it was possible. However, I do not believe any coiler has ever
>>made or could make these measurements.
>
>
>Some sort of average length may be determinable by using a video
>camera

This seems pretty easy to me, is it accurate?  Then again, does the 
accuracy matter that much?  Then again, i guess this is what the whole 
discussion is about.



>>Random sparks can be turned into constant length sparks by using the
>>controlled spark method. The output then becomes a constant energy output
>>that can give a coiler an overall efficiency for his coil that makes sense.
>>This appears to be the only option for the coiler at present.

I have tried the method of using a single shot type setup (with only 1 
spark per second or so), the spark output still seemed quite random :(


I must also comment that the spark lenght formula as it stands is almost 
dead on with my 2 latest systems.  1 is a 15kv 100ma system- spark max 
average 65", formula says 65.8".  My other system is a 15kv 150ma setup, 
max sparks are about 78", the formula says 80.6".  Both systems use a 
120bps rotary and strictly 120v input.  The first system uses a capacitor 
that is 2.5x resocap, the second is roughly 2X resocap.  So there is one 
explanation as to why the second coil performs slightly less than the first 
when comparing to the formula predictions.  So really, it looks like the 
formula does have much validity.

Steve Ward

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