Hi Scott, Brandon, All,
I don't think that there is a specific over-all formula, but here are some "constraining" parameters:
1) Total charge on the toroid Q=0.5CV^2
2) Total energy stored in Toroid E=QV
3) V ~ fn(ROC of topload)
4) If D(toroid)>>>h(coil) or d( toroid)>>d(coil) ==> structural instability
I remember reading, but cannot now find the reference, that it is "desireable" to have ~ half the total sec C be in the topload.
Hope this helps,
Matt D
-----Original Message-----
From: Scott Bogard<sdbogard@xxxxxxxxx>
To: Tesla Coil Mailing List<tesla@xxxxxxxxxx>
Sent: Sun, Sep 26, 2010 11:19 pm
Subject: Re: [TCML] Largest Secondary Coil "Drivable" by Primary Circuit
John,
Good info, I was not aware of this relationship, but it does make sense. It does bring to question however, is there a more concrete formula that relates input power to relative toroid size or capacitance? So if one is designing a system that uses 3kW his toroid size should be X picofarads for longest spark before breakout can no longer occur under normal conditions... It makes me wonder how much bigger I can go on my 4-inch coil that uses a 7*24; the thing makes sparks longer than my old system that happily ran a 12*40 and is consuming about the same power, just a smaller secondary...
Scott Bogard.
On 9/26/2010 8:59 PM, Futuret wrote:
Brandon,
The toroid size should follow the input power, not the secondary
size. If you keep the input power the same, but use a larger secondary,
you should not use a larger toroid (unless the toroid was too small
for the power in the first place). If you increase both the input power and
the secondary size, then the toroid size should also be increased.
If you double the input power, then the toroid should be made
1.4 times larger approximately. For example if the original input
power used a 13" toroid, then when doubling the input power,
you'd use an 18" toroid... just a rule of thumb. The spark length
should also increase about 1.4 times if you double the input power.
If the original spark length was 40" then the new spark length
using double the input power might be 56" or so.
John
SNIP!!
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