Re: Tesla coil output voltage

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Scott Hanson" <huil888@xxxxxxxxxxxx>

JT -

Unfortunately, without having access to sophisticated test equipment you are
not going to be able to determine the "exact" output voltage of your coil.
With no instrumentation and so many variables involved, I think you'd be
lucky to obtain an accuracy of +/- 75 KV by estimation.

The usual "figure of merit" for characterizing Tesla coil performance is by
the length of the discharge arc, determined by slowly bringing a grounded
target into range and measuring the straight-line distance from the toroid
to the target. The frequency with which the arc must strike the target is
not "standardized", but a minimum of once every ten seconds is reasonable.

Note that this method does not take into consideration the "esthetics" of
the discharge. Personally, I find a coil that continuously generates a
multitude of constantly moving air streamers more impressive to watch than a
coil that generates a single long, thin arc to ground.

Regards,
Scott Hanson

----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Sunday, November 27, 2005 5:30 PM
Subject: Re: Tesla coil output voltage


> Original poster: "JT Bowles" <jasotb@xxxxxxxxxxx>
>
> you told me i am about 1/2 way there to a perfect coil, which isnt bad.
Thanks.
>
> NOW TO BUSINESS. I "NEED" TO KNOW WHAT MY OUTPUT VOLTAGE IS FOR SEVERAL
REASONS
>
> *bragging rights(yes...yes...I know)
> *Curiocity, and just need to know, if i am to ever describe its
> output accurately
> *coil is a joint effort by school and I  ( though it is about 99.9999999%
mine)
> *contractual obligation! ha!
> *lastly, i feel obligated to create the best coil possible with my
> resources. IF i discover my output voltage is low, well then, my coil
> isnt the best it can be, is it.
>
> 18 Gazillion volts. Wow buddy, thats some rather serious power. 18
> GAZILLION is enough to ruin your day! haha
>
>
>
>
>  >From: "Tesla list" <tesla@xxxxxxxxxx>
> >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
> >
>
>