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TACAMO

Tue Nov 15 2011, 03:59AM

Registered Member #2794 Joined: Sat Apr 10 2010, 05:13AM
Location:
Posts: 12

Hi, What size secondary could I get with 1257 feet of 26 gauge wire or with 1989 feet of 28 gauge wire? What is the perrfered gauge 26 or 28?

Sulaiman

Tue Nov 15 2011, 06:29AM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

1989 ft of 28 awg would produce a coil 25% longer than 1257 feet of 26 awg of the same diameter. (or 25% larger diameter if coils of same length)

Which is best?
I'd go for 1257 ft. of 26 awg
somewhere between a 6 inch diameter pipe, 15 inches long with 800 turns
and 4 inch diameter pipe, 22 in. long, with 1200 turns.

Mads Barnkob

Tue Nov 15 2011, 11:37AM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

That all depends on what you are building... Is it a SGTC, VTTC, SSTC, DRSSTC?

What power levels are you going to run, what is the rest of your budget for this coil?

If you want general Tesla coil sizing advices, you could easily google you to a lot of information or f.ex. read this:

To play a bit with calculating different secondary sizes, you could f.ex. use the helical coil calclator here:

Tetris

Wed Nov 16 2011, 09:22PM

Registered Member #4016 Joined: Thu Jul 21 2011, 01:52AM
Location: Gainesville, FL
Posts: 660

Just be sure you do not wind the wrong size wire i.e 30 instead of 26, before you realize that it is the wrong size. It will also have crosses in it and you only realize it is bad after you poly it. you will not want to rewind it. So word of advice: be careful and be sure of what you are winding and the wire size.

TACAMO

Fri Nov 18 2011, 12:43PM

Registered Member #2794 Joined: Sat Apr 10 2010, 05:13AM
Location:
Posts: 12

All right, Thanks. Ok here we go, my first build. Here's what I have so far. Don't know what the top load will be yet. Does this all look right so far?

Input Parameters
Input Voltage: 120
Input Freaquency: 60hz
Output Voltage: 7.5kv
Output Current: 35ma

MMC Parameters
20 Caps. Total Capacitance: 13nf

Primary Coil Parameters
Wire Diameter: .25"
Wire Spacing: .25"
Hole Diameter: 6"
Incline Angle: 0

Secondary Coil Parameters
Wire AWG: 26
Winding Height: 20"
Form Diameter: 4"
1,096 Turns, Ratio 5:1, Wire Length: 1,147

Mads Barnkob

Fri Nov 18 2011, 03:29PM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

TACAMO wrote ...

All right, Thanks. Ok here we go, my first build. Here's what I have so far. Don't know what the top load will be yet. Does this all look right so far?

Input Parameters
Input Voltage: 120
Input Freaquency: 60hz
Output Voltage: 7.5kv
Output Current: 35ma

MMC Parameters
20 Caps. Total Capacitance: 13nf

Primary Coil Parameters
Wire Diameter: .25"
Wire Spacing: .25"
Hole Diameter: 6"
Incline Angle: 0

Secondary Coil Parameters
Wire AWG: 26
Winding Height: 20"
Form Diameter: 4"
1,096 Turns, Ratio 5:1, Wire Length: 1,147

Looks good except that your tank capacitor value is close to the resonant value with the transformer, this can damage your transformer due to resonant voltage rise over the transformer. You should take a look at the larger than resonant values underneath.

I ran your numbers through javatc and added a toroid of standard size compared to the secondary size, it could also be smaller.

J A V A T C version 12.5 - CONSOLIDATED OUTPUT
18. november 2011 16:26:32

Units = Inches
Ambient Temp = 68Â°F

------------------------------------------- ---------
Surrounding Inputs:
------------------------------------------ ----------
200 = Ground Plane Radius
200 = Wall Radius
200 = Ceiling Height

------------------------------------------ ----------
Secondary Coil Inputs:
------------------------------------------ ----------
Current Profile = G.PROFILE_LOADED
2 = Radius 1
2 = Radius 2
0 = Height 1
20 = Height 2
1096 = Turns
26 = Wire Awg

--------------------------------------------- -------
Primary Coil Inputs:
------------------------------------------ ----------
Round Primary Conductor
3 = Radius 1
7.871 = Radius 2
0 = Height 1
0 = Height 2
9.7428 = Turns
0.25 = Wire Diameter
0 = Ribbon Width
0 = Ribbon Thickness
0.02 = Primary Cap (uF)
0 = Total Lead Length
0 = Lead Diameter

---------------------------------------- ------------
Top Load Inputs:
------------------------------------------ ----------
Toroid #1: minor=4, major=20, height=23, topload

----------------------------------------- -----------
Secondary Outputs:
----------------------------------------- -----------
211.57 kHz = Secondary Resonant Frequency
90 degÂ° = Angle of Secondary
20 inch = Length of Winding
54.8 inch = Turns Per Unit
0.00231 inch = Space Between Turns (edge to edge)
1147.7 ft = Length of Wire
5:1 = H/D Aspect Ratio
46.4617 Ohms = DC Resistance
29144 Ohms = Reactance at Resonance
0.88 lbs = Weight of Wire
21.924 mH = Les-Effective Series Inductance
22.873 mH = Lee-Equivalent Energy Inductance
22.3 mH = Ldc-Low Frequency Inductance
25.812 pF = Ces-Effective Shunt Capacitance
24.74 pF = Cee-Equivalent Energy Capacitance
44.582 pF = Cdc-Low Frequency Capacitance
6.43 mils = Skin Depth
21.375 pF = Topload Effective Capacitance
116.1873 Ohms = Effective AC Resistance
251 = Q

----------------------------------------------- -----
Primary Outputs:
----------------------------------------- -----------
211.57 kHz = Primary Resonant Frequency
0 % = Percent Detuned
0 degÂ° = Angle of Primary
27.73 ft = Length of Wire
4.6 mOhms = DC Resistance
0.25 inch = Average spacing between turns (edge to edge)
0.867 inch = Proximity between coils
1.32 inch = Recommended minimum proximity between coils
28.418 ÂµH = Ldc-Low Frequency Inductance
0.02 ÂµF = Cap size needed with Primary L (reference)
0 ÂµH = Lead Length Inductance
103.174 ÂµH = Lm-Mutual Inductance
0.13 k = Coupling Coefficient
0.129 k = Recommended Coupling Coefficient
7.69 = Number of half cycles for energy transfer at K
17.99 Âµs = Time for total energy transfer (ideal quench time)

------------------------------------------- ---------
Transformer Inputs:
------------------------------------------ ----------
120 [volts] = Transformer Rated Input Voltage
7500 [volts] = Transformer Rated Output Voltage
35 [mA] = Transformer Rated Output Current
60 [Hz] = Mains Frequency
120 [volts] = Transformer Applied Voltage
0 [amps] = Transformer Ballast Current
0 [ohms] = Measured Primary Resistance
0 [ohms] = Measured Secondary Resistance

-------------------------------------- --------------
Transformer Outputs:
----------------------------------------- -----------
263 [volt*amps] = Rated Transformer VA
214286 [ohms] = Transformer Impedence
7500 [rms volts] = Effective Output Voltage
2.19 [rms amps] = Effective Transformer Primary Current
0.035 [rms amps] = Effective Transformer Secondary Current
263 [volt*amps] = Effective Input VA
0.0124 [uF] = Resonant Cap Size
0.0186 [uF] = Static gap LTR Cap Size
0.0323 [uF] = SRSG LTR Cap Size
48 [uF] = Power Factor Cap Size
10607 [peak volts] = Voltage Across Cap
26517 [peak volts] = Recommended Cap Voltage Rating
1.13 [joules] = Primary Cap Energy
282 [peak amps] = Primary Instantaneous Current
23.4 [inch] = Spark Length (JF equation using Resonance Research Corp. factors)
8 [peak amps] = Sec Base Current

TACAMO

Fri Nov 18 2011, 10:03PM

Registered Member #2794 Joined: Sat Apr 10 2010, 05:13AM
Location:
Posts: 12

Excellent, I can add four more caps to the bank, that would bring it to 15.6nf. Would this be better?

EDIT: Found two more caps. So 16.9nf

TACAMO

Sun Nov 20 2011, 10:45PM

Registered Member #2794 Joined: Sat Apr 10 2010, 05:13AM
Location:
Posts: 12

Hi, I have to redesign my secondary. I was originally planning on building a 20" x 4" secondary which is a 5:1 ratio. But I forgot PVC was measured by the inside diameter. So the 4" PVC pipe I bought has a diameter of 4.5". So now my secondary is going to be 4.5" x 19" which is a 4.2:1 ratio. Is this still good?

Mads Barnkob

Mon Nov 21 2011, 03:56PM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

TACAMO wrote ...

Hi, I have to redesign my secondary. I was originally planning on building a 20" x 4" secondary which is a 5:1 ratio. But I forgot PVC was measured by the inside diameter. So the 4" PVC pipe I bought has a diameter of 4.5". So now my secondary is going to be 4.5" x 19" which is a 4.2:1 ratio. Is this still good?

It is fine, remember that all of these thumb rules are very loose. It also depends on the type of Tesla coil, f.ex. for SSTCs I have used 2:1 secondary coils.

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