[TCML] HOORAY!!! my first coil works!

bartb bartb at classictesla.com
Fri Dec 28 17:02:39 MST 2007


Hi Marko,

Using your caps, can you acquire a few more?

If you put 2 strings of 20 caps in parallel, you'll have 0.05uF (which 
is LTR for SRSG's). Each cap will see about 600V which is excellent. 
You'll have to adjust the tap to 6 turns. This is not ideal, but the 
toroid and coil sets that limit.

Your coil is rather "large". This coil could probably use a larger 
toroid for best performance. Right now your toroid is small for the 
coil. I would prefer to see something in the neighborhood of 9" x 34" 
toroid on this coil. That would require about 7 turns for the tap (which 
is a bit high on inductance, but for good reason).

Now if you would prefer to not source more caps and simply use what you 
have on hand (which is what I would do), then consider the following:

If you really want to give your coil a burst, try .031uF which you can 
do with what you have on hand (1 string of 16 caps). The cap bank will 
be .031uF at 24000 volts. This is LTR for a static gap, but would do 
nicely. If you try this, consider 8 turns on the primary (with your 
existing toroid). If you can build a 9" x 34" toroid, the tap should be 
8.5 turns.

I just wanted to throw those options out there. When it comes to LTR, 
there is the usual static gap LTR value and the SRSG LTR value. I 
personally like to run slightly lower on both for best output (take 
advantage of resonant charging but not so much that you cause a cap or 
transformer failure). This is called optimization in my little book of 
tricks. There are standards, but we have to experiment with those 
standards to optimize.

Another optimization for the future is the secondary itself. It's 
currently rather low turn. Consider the same size coil with 20 awg wire 
for 1000 turns. That would put your primary in the 11 turn range. The 
reason I state this is that I've had better performance near 1000 turns 
than I have at the 700  turn range. I've also had less success with a 
high 2000 turn coil. About 1000 to 1500 turns is good and the reason why 
is the inductance and geometry for the common powers we throw at these 
coils. But that's maybe for your second coil.

Take care,
Bart












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