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Re: [TCML] Turn-to-Turn short circuit
Hi Mathew,
The reason I'm asking about supply transformer is to help you avoid
frustration and mistakes: For example, disregarding various issues about
losses, with your dimensions on the secondary and assuming a small
toroid (say 2" x 10"), the coil would resonate at 138kHz and would
require a .06uF cap size for 10 primary turns to attain resonance (which
is key and fundamental). In order to provide an adequate charge cycle
(ability of power supply to charge the tank cap), the power supply
transformer would need to be nearly 3KVA (example is maybe a 12kV at
250mA output).
There are many problems with your secondary (h/d ratio, high losses,
other downstream needs) and there is the fact that 5MV coils only exist
in the most extreme "Golka" size coils). Our hobby coils are in the 200
to 500 kV range. That's the reality. This can be quite a dramatic
psychological effect on your brain once you realize the details.
The voltage at the output terminal is better described as Vtop = Vpri x
sqrt(Lp/Ls), where Vpri is your peak output supply voltage and Lp and Ls
are the primary and secondary inductances.
Vpri = 12,000 x 1.414 = 16968V.
Lp = 21.71uH
Ls = (90.9mH at resonance)
Vtop = 16968 x sqrt(21.71uH/90.9mH) = 262kV.
Even this is an ideal transformer model. In a practical application,
maybe 70%, so 183kV. Nothing near 5 million volts. This is what you can
expect from your particular secondary. It should be higher for a well
designed sparking Tesla Coil, and about 2x as high. Your secondary
geometry is what should be looked at. The power supply is a good place
to start developing the secondary, and why I ask if you already have a
transformer.
Take care,
Bart
bartb wrote:
Hi Mathew,
Your likely going to get a few replies on the statements below for a
many reasons, but I'm curious, do you already have a transformer you
plan to use? If so, what are is the output voltage and output current
ratings?
Bart
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