Re: secondary output calculations (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: List moderator <mod1@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Sun, 20 May 2007 18:20:48 -0500
From: resonance <resonance@xxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: secondary output calculations (fwd)




Have you tried  Vsec = 80% x Vpri x SQR (Lsec/Lpri) ??

This is very accurate for most medium size coils.

Be sure to note that Vpri depends on your actual spark gap spacing, and it's 
usually not the usual 21 kV peak value.  I have a chart and graph posted in 
the archives that gives accurate Vpri values to use based on your total 
spark gap spacing.

Based on your peak spark length of 5 ft I'm guessing around 350-400 kV 
range.

If you want to know for sure just hook up a big series resistor so it only 
fires approx once every 15-20 seconds.  This spark length measured will give 
you the real output voltage.  A single shot spark does not allow the plasma 
to "grow" and will accurately represent your max potential using standard 
charts.

A single shot pulse mode measurement is independent of the voltage waveform 
and is suitable for all types of waveforms from DC to rapid rise impulse 
voltages with risetimes = or > 0.5 uSec.  Most resonance transformer 
waveforms are in the 3 uSec risetime and are well suited to accurate 
measurement with this technique.  HF potentials up to 1 MHZ can be measured 
with this technique.  Sphere gaps are the preferred method but may "detune" 
the coil slightly so "rod gaps" are typically used for resonance transformer 
measurement.

If you elect to use a standard 1/2 inch dia. "rodgap" protruding off your 
toroid, and sparking to a standard 1/2 inch dia grounded rod, then the 
following is accurate;

50 cm = 278 kV

60 cm = 332 kV

70 cm = 382 kV

80 cm = 435 kV

90 cm = 488 kV

100 cm = 537 kV

The rod gaps should be mounted at least 2 x the gap spacing above ground. 
Humidity correction for resonance transformers is usually around 4.3%. 
Sparkover voltage increases with humidity.  Correction for air density is 
typically 1.5% or less.


Regards,

Dr. Resonance




6-in PVC (6.5od) wound 31-in with 22 AWG single build insulation.  Topload
is 2 toroids, one is 4-15, the other is 7.5-24 (but I am going to swap in
another 7.5-24 to replace the 4-15, I just haven't done it yet).  4 MOT
stack, so about 8kV RMS, ballasted at about 200-250 mA (I'm not exactly sure
about that one, but it is a decent estimate).  My primary cap is 81nf
(measured), and right now I'd getting about 4-5 ft arcs (which seems low to
me, but I have to play with the tuning some, and do  some other small
things.)  My voltage calculations suggested about 500-550 kV out (using 2
different formulas, but I may be mistaken).  Thanks.
Scott Bogard.


>From: "Tesla list" <tesla@xxxxxxxxxx>
>To: tesla@xxxxxxxxxx
>Subject: Re: secondary output calculations (fwd)
>Date: Sun, 20 May 2007 10:37:54 -0600 (MDT)
>
>Original poster: List moderator <mod1@xxxxxxxxxx>
>
>
>
>---------- Forwarded message ----------
>Date: Sun, 20 May 2007 11:24:31 -0500
>From: resonance <resonance@xxxxxxxxxxxx>
>To: Tesla list <tesla@xxxxxxxxxx>
>Subject: Re: secondary output calculations (fwd)
>
>
>
>What size coil, topload, xmfr, and pri cap are you running?  Spark length?
>
>
>
>Dr. Resonance
>
>
>Subject: secondary output calculations
>
>Hey everybody,
>      I have found formulas to calculate the peak voltage put out of a
>Tesla
>coil system, how does one calculate the amperage (please note, I have only
>basic calculus skills).  Does ohms law work?  I am getting ridiculously
>high
>numbers from ohms law, using my calculated peak voltage, my secondary
>resistance, and the impedance from my secondary inductance, capacitance,
>and
>top load capacitance (but my numbers may be off, especially concerning the
>impedances, it has been a little while since I have done that stuff for a
>class).  Thanks.
>Scott Bogard.
>
>
>
>
>
>
>
>

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