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Re: Wire gauge



Tesla List wrote:
> 
> Original Poster: "Samuel Rosset" <samr-at-chez-dot-com>
> 
> I have a problem with converting the gauge in inches, for I have several
> sources and they are different. For example, with one source, a #26 AWG
> would have 58 turns per '' and another one says there are 63 turn per ''
> Does anyone know the diameter for the wires AWG #26, #24 and #22
> 
> Thank you
> 
> Sam

Sam, 

The difference is due to insulation thickness. If you used bare #26 AWG,
you could approach about 63 turns/inch. However, in a working coil
you'll be using insulated wire, and about the best you'll see is 59
turns/inch if you use a single layer of conformal insulation. The
nominal diameter of magnet wire increases as you add successive layers
of insulation (called "builds"). The more build layers, the fewer the
number of turns/inch you'll get (i.e., lower inductance), but the
greater the turn-to-turn insulating capability (better high voltage
stress handling). 

The ACTUAL number of turns/inch that you'll see will usually be a bit
lower, since its quite difficult (on a hand-wound coil, at least) to
consistently get the adjacent turns to butt together together. You can
usually see see some of the coilform peeking between the turns if you
look closely.  To take this into account, I usually derate the number of
turns by multiplying the theoretical turns/inch by an adjustment factor
- typically 94% to 97%. 

Magnet wire can go from single build to quadruple build. A good
compromise is to go with "double build", or "heavy build" wire. The
table below is taken from Essex Wire:

              (Inches)
               Nominal  Turns/ 
AWG:  Build:  Diameter: Inch: 
===   =====   ========  ====
#22    Bare    0.0253   39.5
#22     1      0.0266   37.6
#22     2      0.0276   36.2
#22     3      0.0286   35.0
#22     4      0.0298   33.6
 
#24    Bare    0.0201   49.8
#24     1      0.0213   46.9
#24     2      0.0223   44.8
#24     3      0.0232   43.1
#24     4      0.0243   41.2

#26    Bare    0.0159   62.9
#26     1      0.0170   58.8 
#26     2      0.0179   55.9
#26     3      0.0187   53.5
#26     4      0.0198   50.5

Hope this helps, and good luck on your coil!

-- Bert --