12.1
Wire chart
AWG D.C. OHMS WIRE DIAM APPROX. TURNS PER FEET PER
SIZE PER 1000 FT INCHES INCH, SOLID ENAMEL POUND
COVERED
1 .1264 .2893 X 3.947
2 .1593 .2576 X 4.977
3 .2009 .2294 X 6.276
4 .2533 .2043 X 7.914
5 .3195 .1819 X 9.980
6 .4028 .1620 X 12.58
7 .5080 .1443 X 15.87
8 .6405 .1286 7.6 20.01
9 .8077 .1144 8.6 25.23
10 1.018 .1019 9.6 31.82
11 1.284 .0907 10.7 40.12
12 1.619 .0808 12.0 50.59
13 2.042 .0720 13.5 63.80
14 2.524 .0641 15 80.44
15 3.181 .0571 16.8 101.40
16 4.018 .0508 18.9 127.90
17 5.054 .0453 21.2 161.3
18 6.386 .0403 23.6 203.4
19 8.046 .0359 26.4 256.5
20 10.13 .0320 29.4 323.4
21 12.77 .0285 33.1 407.8
22 16.20 .0253 37.0 514.2
23 20.30 .0226 41.3 648.4
24 25.67 .0201 46.3 817.7
25 32.37 .0179 51.7 1031
26 41.02 .0159 58.0 1300
27 51.44 .0142 64.9 1639
28 65.31 .0126 72.7 2067
29 81.21 .0113 81.6 2607
30 103.7 .0100 90.5 3287
31 130.9 .0089 101 4145
32 162.0 .0080 113 5227
33 205.7 .0071 127 6591
34 261.3 .0063 143 8310
35 330.7 .0056 158 10480
36 414.8 .0050 175 13210
37 512.1 .0045 198 16660
38 648.2 .0040 224 21010
39 846.6 .0036 248 26500
40 1079 .0031 282 33410
41 1323 .0028
42 1659 .0025
43 2143 .0022
44 2593 .0020
45 3348 .00176
46 4207 .00157
47 5291 .00140
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For winding Tesla secondary coils the general consensus is to use
number 22 AWG, or larger diameter, CLOSE WOUND MAGNET WIRE. Often
surplus partial spools of odd wire sizes are found, so I took time
to post a more complete chart of AWG numbers and fractional diameters
than is usually available. All information above is approximate
despite the decimal places. Wire diameter, turns per inch, resistance,
feet per pound, etc. all vary slightly from one manufacturer to another.
Insulation thicknesses will vary depending upon type and the supplier.
Turns per inch will also vary with the quality of the winding. In
practice, Tesla coil windings are not perfect (nor do they need to be)
so expect some slight variations from the specification table above.
Magnet wire coatings from Phelps-Dodge: All data pertain to 18 AWG
magnet wire. Build = thickness of coating
Coating What's it made of Build DC
---------- ----------------- ----- breakdown
Thermaleze-T (TZT) polyester-imide 2.8mils 11kV
Armored Polythemaleze 3.05mils 11kV
(APTZ) modified polyester&
modified polyamide-imide
Imideze (ML) Aromatic polyimide 2.9mils 12kV
Formvar modified polyviynyl 3.0mils 10kV
formal
Sodereze modified polyurethane 2.9mils 8.5kV
Nyleze Polyurethane 2.9mils 8.5kV
& polyamide
* Note: for the dielectric breakdown - These numbers are much bigger than
for bulk materials because they are very thin coatings. The breakdown
field increases as the thickness goes down. {a similar effect happens
in gases and liquids and was studied by Paschen}
Anyway, here's the dielectric constant/DF numbers for these matearials:
Material Dielectric Const. / DF x 10^-3
1kHz 100kHz 1Mhz Rating
TZT 3.7/5.6 3.56/16.4 3.58/21.5 3rd
APTZ 3.86/6.9 3.69/22.1 3.67/26.6 5th
ML 3.34/0.9 3.3/5.7 3.36/9.8 2nd to
teflon
Formvar* 3.6/11.2 3.41/25.2 3.37/28.4 5th
Soldereze 3.85/11.3 3.66/20.7 3.66/23.1 4th
Nyleze 4.07/19.7 3.78/27.1 3.75/27.2 6th
* This shows that Formvar is far from an ideal coating for magnet wire
used in Tesla Coils when compared to something like Polyimide coatings
If this looks like Greek to you please don't dispare. Even the worst
wire coating is acceptable, though noticable improvements in secondary
coil performance will be obtained if you use magnet wire coated with
ML, TZT, or Soldereze. Formvar coated wire is frequently found surplus
on bulk rolls and is cheap by the pound, so don't feel bad if you end
up using it.