If you would like to see some comparative experimental data,
Ben Tongue has performed some experiments and posted the
data to his web site.
http://www.bentongue.com/xtalset/29MxQFL/29MxQFL.html
Yes, it looks like Litz wire has a significant advantage. If I read
the results right, the unloaded Q factor at 943Khz is 141 using solid
copper wire verses a Q factor of 1030 using Litz wire.
That's quite a significant difference. Am I reading the results right?
That's the way I read it. Quite a large difference.
And according to Table 7 using a smaller wire diameter, even with the
higher
DC resistance gives better Q. I found that interesting, I new I could get
higher Q's
when I spaced turns about one wire diameter, but it seem there's a little
more to it.
Oh, and that contrawound thing is neat to. I wonder if there is any
advantage to
three or four contrawound windings.
Great article.
Thanks, Mike
Quote from website:
Table 7: Simulation of inductor BB in FEMM at 1 MHz, with various
conductor diameters (type 61 core material)
Wire dia.
in inches Inductance in uH Resistive
losses in ohms Hysteresis
losses in ohms Total losses
in ohms DC resistance
Q
0.02530 258.5 11.16 1.32 12.48 0.16 130.1
0.02320 259.6 8.04 1.33 9.36 0.18 174.2
0.02127 260.5 6.26 1.33 7.59 0.22 215.7
0.01951 261.1 5.13 1.34 6.47 0.28 253.7
0.01789 261.6 4.37 1.34 5.71 0.36 288.0
0.01265 263.4 2.91 1.35 4.26 0.64 388.1
0.008995 264.0 2.48 1.36 3.84 1.25 431.9
0.006300 264.4 3.02 1.36 4.38 2.62 379.7
0.008995* 264.5 2.57 1.40 3.97 1.00 418.6
Table 7 shows the benefits of space winding when using solid wire. All the
inductors in Table 7 use centered have solenoids of 58 turns and a length of
1.624". The only variable is the diameter of the conductor, which controls
the spacing of the turns (the winding pitch is held constant). The lesson
here is that, when using solid copper wire, there can be a great Q benefit
by space winding the solenoid, using an optimum size wire, in this case a Q
of 431.9 vs 130.1 at 1 MHz.