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Re: [TCML] Subject: current & fuses and toroid diameter, etc @@

-----Original Message-----
>From: FutureT@xxxxxxx
>Sent: Dec 31, 2007 10:44 AM
>To: tesla@xxxxxxxxxx
>Subject: Re: [TCML] Subject: current & fuses and toroid diameter, etc
>In a message dated 12/31/2007 10:50:38 A.M. US Eastern Standard Time,  
>evp@xxxxxxxxxxx writes:
>>>Spark streamers will tend to reach out by  about 3 to 3.5 times
>>>the toroid diameter.  Possibly a little  longer at higher  breakrates.  
>>>Spark streamers will tend  to reach out by 10 or 11 times
>>>the toroid minor diameter.   This is just a rough rule of thumb
>>>that I use.  So it's mostly  the toroid diameter that's limiting
>>>your spark lengths.  Using  700 turns vs. 1000 + turns will
>>>only reduce your spark lengths by  maybe 10% or so.
>> Seems to me  that the terminal diameter would only limit the spark length 
>if the power was  very >high.  Also, IF the secondary is tuned properly, why 
>would the  output voltage be affected by the number >of turns and the secondary  
>Marko mentioned that his spark length was not as long as that  of
>some other coils for the amount of power he was using.  My  comment 
>was specifically for his coil situation.  Once the streamers reach 3  or
>3.5 times the toroid diameter, it's very hard to get longer sparks  at
>120 bps.  Once the sparks reach that length, adding more power tends  to
>create a greater number of streamers, instead of longer  streamers.
>Certainly the sparks will never even reach 3 or 3.5 times the  toroid
>diameter if the power is too low.  Marko is using enough power to  
>create at least 80" sparks, but he's only getting 40" or so.  I  think
>the small toroid is the culprit on his coil.  He may be able to  get
>a little more spark length using his toroid but it may max out at
>45" or 50" the most.  I'm basing all this on a 4" x 15"  toroid.  
>If I'm mistaken, and his toroid is actually larger, then his sparks
>may be longer.  
>Regarding the secondary turns, a greater number of turns  (more
>inductance) may reduce the gap losses by increasing the  pri surge impedance
>as Malcolm used to talk about.  There may be other advantages  of
>using more secondary turns also.  I believe many folks have  reported they
>obtained longer sparks with 1000 or more turns than with 700 or  so.
>If the secondary coil is rather wide, it may be OK to use  fewer
>than 1000 turns and still get a good result.  

I have done a lot of experements just to see the results. I make all of my secondary coils with 950 turns now days.  I have tried secondary coils from 300 turns to 1800 turns.  If your trying to get longer sparks from the top load go with 950 to 1000 turns on the secondary coil.  If you want longer streamers without changing the power supply, top load, caps, caps, gap, etc. wind another 950 turn secondary coil right over the top of the 950 turn secondary coil you already have and connect the 2 coils in parallel.  Two 950 turn secondary coils in parallel with increase the streamers about 10%.  3 secondary coils in parallel will give you another 2%. I have no idea why this works.  If you check arcives way back about 6 or 7 years you will find the details on this.

There is one other thing that works too Mike Hammer told me about this many years ago, I tried it and it works.  Put a resistor on each HV output terminal of your neon transformer.  The resistor needs to be in series with the neon and the spark gap.  If you have a 500 watt power supply then you need 500 watt resistors.  You have to experement with the resistor value it does not work the same on every TC you do this to.  I have about 15 different size and shapes of Tesla Coils I can experement with I have found a 200 ohm resistor works best on one TC while a 600 ohms works best on a different TC and no resistor at all works best on another TC.  GO FIGURE?  I don't recall how much spark length is gaines seems to me it was in the 5% range.  I never felt like 5% was a big deal so I don't do this to my TCs.

If you have a 4" secondary coil powered by 1 neon and a 6" secondary coil powered by 1 neon, everything being the same the larger secondary coil diameter produces longer streamers. Its not a big deal 20" sparks may turn into 22" sparks but the most noticable thing is the spreamer get hotter looking.

If your trying to tweek your coil to get ever ounce of spark output you can possible get then get yourself a varaiac.  Turn the power down very low so the TC is making only 1" sparks from the top load.  If you make an adjustment and the spark increases from 1" to 1.125" that is a 12% increase.  Turn the power up, what was once a 20" sparks should now be very close to a 22.4" spark.  It is much easier to measure those 1" sparks than to measure the 20" sparks.

Many years ago after doing all of these experements I took the best of each experement and combined them all and build a new Tesla Coil.  As I recall the heading of the Thread was, THE BEST OF THE BEST, check the arcives for it.  I didn't do any scientific calculations I just built coils and made observations, some worked good and some worked better.  

Many years ago I was into getting maximum spark output but now days I want a reliable TC that will run for years and never screw up.  I keep several coils set up all the time all I have to do is flip the switch and I can make sparks for 30 minutes if I want.  The only coil I do not keep set up all the time is my 10" coil it makes 12ft sparks I can not fire this up inside my work shop. 

If you want longer sparks build a larger Tesla Coil. 


Gary Weaver

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