To: tesla@xxxxxxxxxx
Subject: Re: Tesla coil output voltage
Date: Sun, 27 Nov 2005 12:46:34 -0700
Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>
At 09:12 AM 11/27/2005, Tesla list wrote:
Original poster: "JT Bowles" <jasotb@xxxxxxxxxxx>
I need to know, for sure, what my coil produces.(voltage & current)
Why do you need to know "for sure"? Curiosity? Bragging rights?
[My coil puts out eighteen gazillion volts and your piddly effort
puts out a mere million!] Scientific research? [The output voltage
of the coil, measured by calibrated E-field probes at distances of
1, 2, and 3 meters, is 142 kV(measurement uncertainty of 3kV, 1
sigma) Science project for school?
Contractual Obligation? [Vendor shall provide a tesla coil with an
output voltage of no less than 400 kilovolts]
That will determine how you go about answering the question.
I can tell you all humidity, spark distance, breakrate of topload,
and resonant frequency of secondary, and much more.
* currently its about 70% humidity
* my topload breaks out at 210 Hz
* unloaded secondary is 240KHz
* maximum spark distance is 15.5 inches
* topload is 10.5 inch diameter toroid, 3.5 inches thick
* topload is semi-smooth Aluminum air ducting w/ foil tape all over it
* no clue about output current
can you tell me, with this informartion what the output voltage is?
Current would be nice too, but il need to measure that one somehow.
Max spark distance doesn't tell you much in this circumstance.
The useful thing to know would be what's your power source (a NST?)
and how big is your primary capacitor.
The Vsec = Vpri * sqrt(Lsec/Lpri) approximation might also be
useful, since the inductances can be determined pretty much by
calculation from dimensions.
Your rough surfaced toroid with 3.5" diameter tubing will also limit
things.. If the inductance calculation comes up with 600 kV, that
will be unrealistic.
If you're using a 12kV 30mA transformer... that's 360VA.. You can
probably get 20% more by overvolting it.. call it 450VA.. The rule
of thumb spark length you'll get, with everything optimized will be
around 3'. You're about half way there, which isn't bad.
Borne coiler,
JT Bowles