Re: Desktop Bipolar Coil

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

Original poster: "Barton B. Anderson by way of Terry Fritz <teslalist-at-qwest-dot-net>" <classictesla-at-netzero-dot-com>

Hi John F / John C / All -

We always go round on this, don't we...

JF, I didn't read JC's post as pertaining to twin coils, but just rather a 
comparison of 25.5" vs an arbitrary 36" spark length..., but that's neither 
here nor there.

I've learned to relax a little and simply realize that the JF equation 
tells me with a given input watts, my "eyes" will see "X inches" of spark 
(if all goes well). That in my book is "no-nonsense" engineering. It's a 
good ballpark, and for the majority of coilers, it works. If actually 
"measuring" spark length to define why it reaches a max/min/avg  value at 
given lengths, the equation does not apply.

Take care,
Bart

Tesla list wrote:

>Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" 
><FutureT-at-aol-dot-com>
>
>In a message dated 6/30/03 1:29:30 AM Eastern Daylight Time, 
>tesla-at-pupman-dot-com writes:
>
>John C,
>
>Comments below.....  oh  BTW, it's not a random spark length I'm
>considering, it's a maximum spark length.
>
>>John F. -
>>
>>This is what I mean by nonsense engineering when using random TC spark
>>outputs. This possibility also occurs with other engineering systems. Your
>>spark 36 inch length can be real, however, the exact watt second input to
>>produce this spark cannot be determined and the spark length should not be
>>compared to other spark lengths with an assumed same watt second input. Keep
>>in mind that the random spark length also has a random watt second input for
>>that particular spark. With most engineering systems random outputs can lead
>>to over unity energy.
>>
>>For example -
>>
>>7500 x .03 = 225 watts
>>
>>John Freau equation -
>>
>>   spark inches = 1.7 sqrt(watts)
>>          = 1.7 x sqrt(225)
>>          = 25.5 inch spark
>
>
>
>Correct so far.....
>
>
>>John Freau 36 inch spark -
>
>
>
>Now where did this 36" spark come from?  Did you perchance
>take the spark length for a *twin* coil?  Twins give longer sparks
>than a regular coil, and I use a different formula for them.  I posted
>about this very recently.  In fact I mentioned that a 7.5/30 may give
>a 36" spark in a twin coil.  My guess is you must have taken that
>figure.  Unfortunately that's mixing apples and oranges.
>
>
>>   watts = (inches/1.7)^2
>>      = (36/1.7)^2
>>      = 448 watts
>
>
>
>This is correct for a 448 watt input for a regular coil, but for a twin
>you only need 225 watts for a 36" spark.  More on that below.
>
>
>>   unity eff = 448/225
>>        = 3.96 = 396% over unity energy
>
>
>
>I believe you are confusing the results for a twin coil with results for
>a regular coil.  That would indeed give a nonsense result if that's what
>you did.  I recently answered a post about a twin coil, and you may
>have missed that distinction.
>
>
>>It is amazing what you can do with numbers using random sparks!
>>
>>This is the penalty that coilers must pay for using random TC spark lengths.
>>Hopefully, in the future TC spark lengths and watt second inputs will be
>>better defined.
>
>
>
>There is no penalty at all.  But one must be accurate in selecting
>the proper formula.  I'll explain it again.
>
>Using a 7.5/30 NST for a normal TC:
>
>   spark length inches = 1.7*sqrt input watts
>
>                        25.5" = 1.7*sqrt 225
>
>Using a 7.5/30 NST for a twin TC:
>
>   spark length inches = 2.4*sqrt input watts
>                       36" = 2.4*sqrt input watts
>
>The reason twins give longer sparks for a given input power is
>because a twin coil can be considered to be two coils each of
>one half the total input power.
>
>I hope this helps to clarify the situation.
>
>John F.
>
>
>
>>John Couture
>>
>>--------------------------------
>>
>>
>>-----Original Message-----
>>From: Tesla list [mailto:tesla-at-pupman-dot-com]
>>Sent: Saturday, June 28, 2003 9:18 PM
>>To: tesla-at-pupman-dot-com
>>Subject: Re: Desktop Bipolar Coil
>>
>>
>>Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>"
>><FutureT-at-aol-dot-com>
>>
>>In a message dated 6/28/03 1:00:09 PM Eastern Daylight Time,
>>tesla-at-pupman-dot-com writes:
>>
>> >. It is my understanding the John Freau's equation for
>> >spark length is only good for NSTs when the NST is modified.
>> >
>> >John Couture
>>
>>
>>John,
>>
>>My equation is good for NST's whether they are modified or not.
>>One should use the measured input wattage for the calc, or at
>>least the PF corrected VA which should be a reasonably accurate
>>approach too.  Consider for example John Morawa's beautiful
>>15/30 NST coil which gave 40" sparks from an unmodified NST,
>>at 120 volts input.
>>
>>John
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