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Re: Tesla Coil toroid Size


  Bart -

  Changing from one toroid to another toroid may not give enough change in
energy to be detected at the input. What sizes were the toroids? Try the
large toroid vs a 2 or 3 inch sphere, if the TC can be tuned.

  Did you say that the spark did not lenghten when you used the larger
toroid? This is contrary to what other coilers have found. However, this is
possible if some other parameter changed such as finding the proper tune
point. 

  Try using controlled sparks (continuous horizontal sparks from the toroid
to a ground point).

  When using non-controlled sparks you will have to break down the input
energy into the watt seconds for each streamer because they are varying.
This means you will have to measure the integrated watts over the fraction
of a second that the streamer occurs. As I said this is difficult and maybe
impossible.  

  This is only part of the story. You are using only a voltmeter and
ammeter. This gives you volt amps. You also need a wattmeter or a power
factor meter to check the change, if any, in the power factor. However, you
may not have to go to all this trouble if you use the controlled spark and
it lenghtens. You can expect that the extra energy for the longer
controlled spark came from an increase in the input energy. That is one of
the advantages of the controlled spark, it gives you a constant load and
you do not have to mess with the fractions of time for each streamer.

   Measuring current at the sparkgap will do no good because this will not
show you the increase in input watt seconds or energy if the spark is
longer and no other changes are made.

  The em field is of little significance in this case because we are only
interested in input energy vs output energy.

  It should be noted that an increase in the output spark requires very
little energy. This means that the increase in input amps could be very
small and hard to detect if the current is varying as much as 5 amps. Using
controlled sparks would help to make detection easier. Your ammeter may
need more dampening.

  This type of testing is not simple and can take a lot of time and
instrumentation to get it right. This is no doubt why it has never been
done before (input measured). I did this test several years ago and the
controlled sparks did lenghten. I just assumed the input energy had
increased. I did not have the instruments to measure the input.

  John Couture

------------------------------------- 


At 01:16 PM 9/13/98 -0600, you wrote:
>Original Poster: "Barton B. Anderson" <mopar-at-uswest-dot-net> 
>
>John, All,
>What would be a valid measuring technique(s) for
>measuring input watts under normal TC operation
>(non-controlled sparks)? My coil setup includes a Vrms
>meter and current meter at the control box before the
>transformer. I usually set my input voltage to a given
>value, then increase my inductive ballast until the
>sparks start flowing. When this occurs, I do not see
>variation on the voltage, but the current meter jumps
>about 5 amps back and forth during operation. I placed a
>larger toroid on my TC this weekend (Ed Sonderman
>Dual-Stack style - retuned coil of course) and ran it
>for about 10 minutes. I did not notice any change in
>current as with my single toroid. I deduct from this
>that input watts did not increase with the larger
>toroid. I should note that my output sparks did not
>increase or the output type (multiple streamers). My
>coil apparently wants a larger toroid.
>
>Is it possible that smaller toroids are deep in the em
>field and larger toroids are physically nearer the edge
>of the em field thus changing breakout conditions? I'm
>not sure how large a typical em field is. I'm just
>contemplating the hypothesis.
>
>The input current is the current charging the cap. I
>think measuring current at the sparkgap may be a more
>valid test. Any thoughts anyone?
>
>Bart
>
>Tesla List wrote:
>> 
>> Original Poster: "John H. Couture" <couturejh-at-worldnet.att-dot-net>
>> 
>>   John F -
>> 
>>   I was happy to hear that someone had performed the input watts test.
>> There are several possibilities why you did not find an increase in the
>> input watts when you increased the toroid size. One reason could be that if
>> you were not using controlled sparks the varying streamers would make it
>> difficult if not impossible to correlate the streamer energy with the input
>> energy (watt seconds).
>> 
>>   When you say that the larger toroid holds more energy for fewer streamers
>> do you mean that the toroid is storing energy from more than one bang? As
>> you know I mentioned this in a past post and there were so many members
>> that felt this was impossible they almost convinced me that I was wrong.
>> However, it may be that energy is stored in the electric field surrounding
>> the coil but not in the toroid.
>> 
>>   Even with controlled sparks the increase in input watts when the toroid
>> is increased may be hard to detect if the input is varying. A small
>> increase in the spark length does not require much energy. What were your
>> input and output conditions when you made your tests?
>> 
>>   John Couture
>> 
>> ---------------------------------
>
>
>