Re: General Coil Design

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Bart Anderson <classi6-at-classictesla-dot-com> 

Hi  Ian,

I just ran Javatc with the 6" x 32" (1220 turns) using your .6mm wire size 
(246kHz). I ran both meters and inches and pasted them below for your 
reference (just the secondary related info). There must have been an input 
error to get a 100kHz output from Javatc. Reference my inputs below (you 
will probably quickly identify where the error was).

If you (or anyone) is having any type of difficulty with Javatc, please 
email me. I'm just a click away. I'm happy to help (any time).

As far as the coil is concerned. The h/d ratio looks good and the coil size 
looks good. The .6mm is a good size and is near 21 or 22 awg. This about 
perfect. I suspect you will have a great working coil. I would recommend 
however that you do consider the entire design before actually building, 
mainly to ensure a good fit with the relationship between tank capacitance 
and inductance. Also, consider the topload in these decisions.

Take care,
Bart

J A V A T C v.10 - CONSOLIDATED OUTPUT
Monday, December 08, 2003 6:32:08 PM

Units = meters
----------------------------------------------------
Secondary Coil Inputs:
Current Profile = G.PROFILE_BARE
0.076199 = Radius 1
0.076199 = Radius 2
0 = Height 1
0.8128 = Height 2
1220 = Turns
0.0006 = Wire Diameter

----------------------------------------------------
Secondary Outputs:
246.97 [kHz] = Secondary Resonant Frequency
90 [deg°] = Angle of Secondary
96.838 = Turns Per cm
0.00662 [cm] = Space Between Turns (edge to edge)
20 [awg] = Recommended Wire Size
584.11 [meters] = Length of Wire
5.33 = H/D Aspect Ratio
35.625 [ohms] = DC Resistance
52731 [ohms] = Reactance at Resonance
1.47 [kg] = Weight of Wire
33.982 [mH] = Les-Effective Series Inductance
31.762 [mH] = Lee-Equivalent Energy Inductance
39.105 [mH] = Ldc-Low Frequency Inductance
12.221 [pF] = Ces-Effective Shunt Capacitance
11.44 [pF] = Cee-Equivalent Energy Capacitance
21.714 [pF] = Cdc-Low Frequency Capacitance
0.133 [mm] = Skin Depth
0 [pF] = Topload Effective Capacitance


Here's a check using inches:
J A V A T C v.10 - CONSOLIDATED OUTPUT
Monday, December 08, 2003 6:38:59 PM

Units = inches

----------------------------------------------------
Secondary Coil Inputs:
Current Profile = G.PROFILE_BARE
3 = Radius 1
3 = Radius 2
0 = Height 1
32 = Height 2
1220 = Turns
0.02362199 = Wire Diameter

----------------------------------------------------
Secondary Outputs:
246.97 [kHz] = Secondary Resonant Frequency
90 [deg°] = Angle of Secondary
38.1 = Turns Per inch
0.00261 [inch] = Space Between Turns (edge to edge)
20 [awg] = Recommended Wire Size
1916.4 [ft] = Length of Wire
5.33 = H/D Aspect Ratio
35.63 [ohms] = DC Resistance
52731 [ohms] = Reactance at Resonance
3.24 [lbs] = Weight of Wire
33.982 [mH] = Les-Effective Series Inductance
31.762 [mH] = Lee-Equivalent Energy Inductance
39.105 [mH] = Ldc-Low Frequency Inductance
12.221 [pF] = Ces-Effective Shunt Capacitance
11.44 [pF] = Cee-Equivalent Energy Capacitance
21.714 [pF] = Cdc-Low Frequency Capacitance
5.229 [mils] = Skin Depth
0 [pF] = Topload Effective Capacitance


Tesla list wrote:

>Original poster: "Ian McLean" <ianmm-at-optusnet-dot-com.au>
>Hello Coilers,
>
>I have been lurking on this list awhile.  I have been playing with
>electronics and high voltage for a long time in one form or another but
>still have not built a coil.
>
>I have done a lot of research over the last few years on the Web on Tesla
>Coils, and am in the process of building my first Tesla Coil now :)
>Whilst
>I am no newbie to electronics or high voltage I am certainly a newbie to
>coiling, so I have some general design questions for obtaining optimal
>performance.
>
>I have built my HV supply.  I have 2 x 15/60 NST's.  I have built a HV RC
>filter and protection gap for the NST's.  I have built an AC control box
>with a 2kVA variac.  I have tested this setup on a Jacob's Ladder, and it
>works real well.  Tested AC draw from the wall.  With a single 40uF PFC cap
>for both NST's, and the Jacob's Ladder running, AC current draw from 240
>volt mains averages out between 5 and 6 amps.  I have an 8 Amp breaker in
>the AC control box and it has not tripped yet.  So far so good.
>
>I have ordered 60 x Cornell Dubelier 942C20P15K 0.15uF 2000V caps from
>Richardson Electronics here in Sydney Australia.  They arrive in 2 days.  I
>am so excited.  I can build my MMC now :)  Getting closer ....
>
>I seem to be building this coil back-to-front compared to a lot of people.
>I haven't built the actual coil primary or secondary yet ...  I am building
>it from the power supply up rather than the other way around.
>
>For my MMC, I am planning on building 5 strips of 12 caps.  I'll build the 5
>units separately so I can play with cap size.  I'll use 10M 1/2W resistors
>as bleeders as suggested by the Geek Group.
>
>If I use all five strips in parallel, that gives me 67.5nF  tank cap.
>This
>is very close to the LTR cap size recommended for an SRSG gap by the Geek
>Group for a 15/120 supply.  If I use 2 or 3 strips, this gives me roughly
>the LTR cap size for a static gap (about 37.5nF).  I have a 600W motor, and
>am planning to modify it for salient pole synchronous operation.  I am
>building a sucker gap as well, so I will have the ultimate in flexibility.
>
>Now you have my history, comes my question.  Secondary coil design.  I
>originally thought 1mm enamelled copper.  About 750 turns on 200mm form.
>160kHz resonant frequency.  I thought this would give me some headroom if I
>decide to get a pig later.  Got these design specs from a coil on Herb's
>tesla Page for a similarly powered transformer.  Then I spoke to Claude,
>also here in Sydney, and an experienced coiler, whom suggested that my
>selection for copper was too thick, and turns too few.  He suggested that I
>choose 0.6mm copper and go for 1000-1200 turns on a 6 inch former for a
>secondary length of 30-32 inches.  I have plugged these figures into JavaTC
>and cannot for the life of me get the results I am expecting.  The
>calculated resonant frequency is below 100kHz, which can't be right.
>
>I am after the same thing as everyone else of course, the longest possible
>streamers, so my question is what secondary design would be optimal for a
>15/120 supply with the tank circuits I have described ?  This really is a
>general question for everyone's benefit I figure, as this seems to be about
>the power level that many coilers are using.
>
>Sorry for the long email.
>
>Rgs
>Ian
>
>
>
>