[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [] conical secondary (fwd)
---------- Forwarded message ----------
Date: Sun, 17 Jun 2007 13:13:15 -0700
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: [] conical secondary (fwd)
Hi Dave,
I got your specs, thanks. Interesting model. Your measurements look good
to me. To look at your coil, which really is a 3 coil system where
L1=flat primary, L2=flat disc driver, L3=helical solenoid, I had to
model it a couple different ways using a home version of Javatc that
allows me to rim ground the disc (as you have it connected). I find this
configuration similar to my hybrid maggy. To look at all 3 coils, L3 is
placed as a cylinder object (same dimensions and placement of L3).
Here's what it looks like minus the pvc:
http://www.classictesla.com/temp/DaveThomson-1.gif
I obviously had to guess at wall dimensions, post lengths at the bottom
of the sphere and center of the flat disc, primary, etc., but I think
close enough to see what's going on. Below are my IO's from Javatc. To
sum it up, the driver section (L1 and L2) are resonating at 418 kHz
according to Javatc, but of course your measured 428 kHz is real. L3 is
being seen as a topload object more than it is a coil. As a matter of
fact, if you replaced L3 with a cylinder the same dimensions and
placement, the coil would likely act exactly same. Your L measurement is
good. But the back calc of 19 pF is not. If you used the measured Ldc
inductance with the operating frequency of 428kHz to back calc that
value, then there's a problem as the high frequency inductance should be
used. BTW, I didn't tune anything in the primary, just placed it there.
Coupling is extremely high at k=0.661 between L1 and L2 and total energy
transfer is a ripping 1.5us!! This is maggy territory. The spark gap
could have some issues here. I can see why you get the hot white discharges.
I also modeled L2 and L3 and placed the primary as grounded objects (I
do that by using the disc inputs and basically placing rings in place of
the actual primary wires).
http://www.classictesla.com/temp/DaveThomson-2.gif
The helical coil is resonating at 1300 kHz! Way out there compared to
the rest of the system. I didn't check to see if it's running at f2 or
not. It may be set to 3/4 wave? Coupling is low about 0.023. I can send
you that data if you like also. It would interesting to match all 3
coils to resonance. It would of course change the whole system when that
is done and it's difficult to match 3 coils all in such close proximity
to each other (been there, done that). The problem here is the slender
helical coil. You would need to lower frequency of that coil but you
really don't want to make it taller and a larger coil would not be ideal
above L2. But maybe an inverse cone (small at the bottom near L2 and
wide at the top?).
Anyway, very interesting. This setup in my mind is a close proximity 3
coil system (regardless of the connection between L2 and L3). I don't
think you need a "physical" connection if L3 was tuned to L1 and L2.
Take care,
Bart
----------------------------------------------------------------------------
Dave Thomson : L1=Flat Primary, L2=Flat Disc, L3=Helical Coil.
Coils modeled are the Flat Disc and Flat Primary.
The helical coil is modeled as a topload cylinder object.
This particular situ will show the total system resonance you would
measure with a scope.
J A V A T C v.10 - CONSOLIDATED OUTPUT
Sunday, June 17, 2007 11:12:41 AM
Units = Inches
Ambient Temp = 68°F
----------------------------------------------------
Surrounding Inputs: MY BEST GUESS
----------------------------------------------------
100 = Ground Plane Radius
100 = Wall Radius
100 = Wall Height
100 = Ceiling Radius
100 = Ceiling Height
----------------------------------------------------
Secondary Coil Inputs: FLAT DISC L2
----------------------------------------------------
Current Profile = G.PROFILE_LINEAR
12.625 = Radius 1 <==Grounded end
0.125 = Radius 2 <==HV end
30 = Height 1
30 = Height 2
144 = Turns
12 = Wire Awg
----------------------------------------------------
Primary Coil Inputs: FLAT DISC L1
----------------------------------------------------
10.25 = Radius 1 <==BEST GUESS BASED ON PICTURE
11.25 = Radius 2
30.35 = Height 1
30.35 = Height 2
4 = Turns
0.125 = Wire Diameter
0.009 = Primary Cap (uF)
24 = Total Lead Length
0.1 = Lead Diameter
----------------------------------------------------
Top Load Inputs:
----------------------------------------------------
Sphere #1: horz=4, vert=4, height=64.5, topload
Cylinder #1: diam=1.3125, bottom_h=32, top_h=59.5, topload <==HELICAL COIL
Cylinder #2: diam=0.25, bottom_h=61, top_h=62.5, topload <==TOP POST
Cylinder #3: diam=0.25, bottom_h=30, top_h=32, topload <==BOTTOM POST
----------------------------------------------------
Secondary Outputs:
----------------------------------------------------
418.54 kHz = Secondary Resonant Frequency <==TOTAL SYSTEM RESONANCE
0 deg° = Angle of Secondary
12.5 inch = Length of Winding
11.5 inch = Turns Per Unit
480.7 ft = Length of Wire
0.76 ohms = DC Resistance
9037 ohms = Forward Transfer Impedance
3.388 mH = Les-Effective Series Inductance <==HIGH FREQ INDUCTANCE
4.705 mH = Ldc-Low Frequency Inductance <==NEAR LCR MEASUREMENT
42.677 pF = Ces-Effective Shunt Capacitance <==HIGH FREQ CAPACITANCE
106.784 pF = Cdc-Low Frequency Capacitance
4.43 mils = Skin Depth
----------------------------------------------------
Primary Outputs:
----------------------------------------------------
354.65 kHz = Primary Resonant Frequency <== NOT TUNED. I SIMPLY
POSITIONED IT.
0 deg° = Angle of Primary
22.51 ft = Length of Wire
0.125 inch = Average spacing between turns (edge to edge)
0.247 inch = Primary to Secondary Clearance
21.63 µH = Ldc-Low Frequency Inductance
0.746 µH = Lead Length Inductance
210.981 µH = Lm-Mutual Inductance
0.661 k = Coupling Coefficient <== WOW!! VERY HIGH COUPLING!!! YOU'VE
GOT A FLAT MAGGY!!
1.51 = Number of half cycles for energy transfer at K
1.5 µs = Time for total energy transfer (ideal quench time) <== NOW
THAT'S FAST!!!
Tesla list wrote:
>---------- Forwarded message ----------
>Date: Sun, 17 Jun 2007 07:19:10 -0500
>From: David Thomson <dwt@xxxxxxxxxxxx>
>To: 'Tesla list' <tesla@xxxxxxxxxx>
>Subject: RE: [] conical secondary (fwd)
>
>Hi Bart,
>
>The specs are on the link I gave.
>
>When I say, "practically no coupling," it should be obvious I'm referring
>strictly to inductive coupling. Of course there is electrical coupling as
>electrical current drives the resonator. Also, there is some degree of
>capacitive coupling.
>
>However, if I understand resonance correctly, the center of the flat spiral
>coil will be out of phase (inductively) with the solenoid coil, especially
>since the two coils are tuned to different (although harmonic) frequencies.
>Further, the magnetic field at the center of the coil is 90 degrees tilted
>from the magnetic field where the primary and secondary couple. There is no
>way they can be inductively coupled.
>
>These particular coils were built to quarter wavelength specs based upon
>wire length. The solenoid coil had a wire length three times that of the
>flat spiral. The mistaken idea I had at the time was to place the node of
>the overall oscillation at the connection point of the two coils. To begin
>with, the node would have been at 22.5% of the total wire length, not 25%.
>Also, it appeared the solenoid resonated independently of the flat spiral
>secondary, as evidenced by the topload standing wave and misplaced node.
>
>Dave
>
>David W. Thomson
>
>
>
>>-----Original Message-----
>>From: Tesla list [mailto:tesla@xxxxxxxxxx]
>>Sent: Saturday, June 16, 2007 9:51 PM
>>To: tesla@xxxxxxxxxx
>>Subject: Re: [] conical secondary (fwd)
>>
>>
>>---------- Forwarded message ----------
>>Date: Sat, 16 Jun 2007 20:26:45 -0700
>>From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
>>To: Tesla list <tesla@xxxxxxxxxx>
>>Subject: Re: [] conical secondary (fwd)
>>
>>Hi Dave,
>>
>>What do you mean that the solenoid has practically no coupling?
>>Certainly it does. There is both electrical connectivity and
>>mutual inductance between those two coils. They definitely
>>couple to each other and probably a good value considering
>>their proximity. Give me specs on the two coils and I'll tell
>>you how much.
>>
>>How did you measure coupling between the two?
>>
>>Take care,
>>Bart
>>
>>Tesla list wrote:
>>
>>
>>
>>>---------- Forwarded message ----------
>>>Date: Sat, 16 Jun 2007 21:17:12 -0500
>>>From: David Thomson <dwt@xxxxxxxxxxxx>
>>>To: 'Tesla list' <tesla@xxxxxxxxxx>
>>>Subject: RE: [] conical secondary (fwd)
>>>
>>>Hi Scott,
>>>
>>>
>>>
>>>
>>>
>>>> Did anybody consider a flat secondary with a helical
>>>>
>>>>
>>resonator in
>>
>>
>>>>a magnifier setup? My thinking is that would give the absolute
>>>>maximum current (from the flat secondary) and potential (from the
>>>>helical resonator).
>>>>
>>>>
>>>>
>>>>
>>>This is essentially my setup:
>>>http://www.tesla-coil-builder.com/FlatSpiralSolenoidCombo.htm
>>>
>>>A tall solenoid coil has practically no coupling when
>>>
>>>
>>connected to the
>>
>>
>>>center tap of a flat spiral coil. The solenoid is operating
>>>
>>>
>>as a resonator.
>>
>>
>>>That is how I generated the coronal standing waves (longitudinal,
>>>scalar, whatever you want to call them) on the topload.
>>>
>>>Dave
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>
>
>
>
>
>
>
>