Re: [TCML] Magnifier topics

[Harvey Norris <harvich@xxxxxxxxx>]

--- On Thu, 2/11/10, Paul Nicholson <tcml88@xxxxxxxxxxx> wrote:

> From: Paul Nicholson <tcml88@xxxxxxxxxxx>
> Subject: [TCML] Magnifier topics
> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> Date: Thursday, February 11, 2010, 8:50 AM
> David Sharpe wrote (in another
> thread):
> 
> > I suspect the connection you are alluding to is that
> the
> > "driver secondary + transmission line" acts as a 1/2
> wave...
> 
> > If that is true, an electrical high stress "node"
> would
> > (should) appear mid-way up the driver secondary.
> 
> Yes.   Actually there are two 3/4 wave modes
> coming into play!
When you are speaking of operating in 3/4 wave mode in the magnifier arrangement; does this imply changing the  primary frequency choice? This sounds like a self evident question since it is undoubtably true, that if the primary and secondary were in operation without addition of the tertiary coil, its frequency of operation can be based on the quarter wave value. If I understand things correctly this should then also reduce the primaries frequency of operation, since now 50% more wire length as tertiary coil line connection has been added. But then we should say the entire operation is using a quarter wave mode changed to a 3/4 wave one, so being somewhat confused here let me cite the actual example I will be working on this spring.
47 Turn/ 10 ft Diameter/1500 ft 14 gauge Secondary for Magnifier Experiments.
http://www.flickr.com/photos/harvich/3933345200/
Primary later placed as three winds of thick
insulated 00 gauge aluminum around the base circumference laterally outwards from the first wind, so that the primary has a better mutual inductance with the driving secondary. 

Now here I will assume that since the secondary windings are at 1 inch separation, we can use the quarter wave formula as a good approximation of the secondaries resonant frequency using 1500 ft of wire, the wavelength being 6000 ft, the reciprocal of the time period at c is ~ 163,700 hz.
By adding 50% more wire length from line connected tertiary coil should we then not drive the primary at 2/3 the former frequency, or 108 khz?
The tertiaries I was planning on using for this experimentation are small in comparison to the secondary itself; they are 4.5 in OD PVC tube TC secondaries of 1 and 2 ft, the longer being 1791 ft of 23 gauge wire, and the one ft model being half of this at ~895 ft. According to the interpretation being made here I see that I should be then aiming for a tertiary of 750 ft, of half of the secondary length. My next question becomes do these length ratios between secondary and tertiary, if not obeyed in the construction details detract from the magnifiers performance due to improper node and antinode placements?

I see here that the 895 ft secondary 1 ft coil length as tertiary should be tried first, where here a good experiment can be made by altering the ending top load of this final coil, so that it can act as 750 ft quarter wave resonator as required. To do this however would require that the top load itself must reduce the tertiaries resonant frequency to that of one BELOW its quarter wave value. It would seem that quite a guessing game of the proper tertiary dimensions for this 1500 ft secondary may be involved. I may have this all mixed up about the proper driving primary frequency, so if corrections can be made by other comments, please indicate so. For noting differences of top load operation a special option here has been designed where I have used this for other "off TC coil topic" investigations of this somewhat unique secondary having little to no internal capacitance. My first signal generator tests of the coil did not show the typical loss of
 impedance at its predicted resonant frequency, but a long base delivery wire was used in that test. 
As incredible as it sounds the coil with its elevated top load may detect varying ground conditions. The top load at ~ 25 ft elevation;
Sideways View of Secondary and Central Tower Globe/ June 30/09. 
http://www.flickr.com/photos/harvich/3933314910/
A pvc tube insulation is used between the top of the tripod tower, which the entire tower of course becomes the ground connection, and a top inverted brass dome bowl. Below this dome is a 4 inch neon bulb metallically connected to the dome, and given an independent ground connected at the base of the tower. A special air core 60 hz resonant circuit using a 70 lb coil of 23 gauge wire, having a series resonant q factor in the 15 range @ 60 hz can be connected at its midpoint voltage rise to the base of the secondary and its ending connected to the domed neon/ ground end path shows that when the bulb ignites to the ground path, it in turn quenches the voltage supplying it, as the resonance has essentially been grounded out, reducing the voltage back down to that found in its reactive state. During the time period where this bulb discharge has been extinguished, the 60 hz series resonance has again become disconnected from that grounding and is free again
 to engage in a repeated cycle of voltage rise, where after ~ three of these AC  60 hz cycles, the voltage again becomes high enough to ignite the bulb, which in turn again quenches itself. This happens about 20 times/sec, where here a shaky camera picture shows a night time neon discharge below the dome.
http://www.flickr.com/photos/harvich/3932481603/ 
During an approaching thunderstorm the neon discharge will be disabled before the tower itself sees a drop of rain. The voltage is prevented from reaching the tower top by leakage of the coil to its environment. Morning glory vines were grew around the tower to see if this would also be an issue, where it certainly shows that alternative ground paths around the coil through the moisture in the vines does inhibit the process, to the point where late in the year, the neon discharge would now no longer even work. After the vines dried up through winter, the process now once again works. Dismissing these off topic investigations I would again assume that the elevation of the top load; once an intervening tertiary coil has been added in series, will do a good job of reducing that tertiaries higher frequency desired 750 ft oscillation, even though the wire length itself at ~900 ft is itself 20% too high.
> The lower frequency one has a 1/2 wave spanning the
> secondary, a
> voltage node (zero) on the transmission line, and the
> tertiary +
> topload makes up the remaining 1/4 wave.  This is the
> resonance
> you describe.
> 
> But there is another 3/4 wave mode present too, at a
> higher
> frequency.   This one has 1/4 wave along the
> secondary, a
> voltage antinode (max) coinciding with the transmission
> line
> and the tertiary + toroid spans the 1/2 wave, with a
> voltage
> node (zero) somewhere inside the tertiary.
For this mode of operation would not the longer 2 ft secondary using 1790  ft of wire be a better choice? Perhaps both one and two ft height 23 gauge tertiaries could be placed slightly above the ending wire periphery of this larger secondary... Is there also an issue that tertiaries need to be in isolation from the secondaries magnetic field? I do not understand why this is said, since both fields should be able to act in unison, and perhaps one might even reinforce the other just on the tertiary side itself.
Sincerely
Harvey D Norris


  
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