Hi Mikek:
Do you have a link to "The Litz man's page"?
I think 2.46? comes from taking the differential of a simple
equation for the inductance of a single layer cylindrical coil.
--
Have Fun,
Brooke Clarke
axioms:
1. The extent to which you can fix or improve something will be limited by how well you understand how it works.
2. Everybody, with no exceptions, holds false beliefs.
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On Sat, Sep 24, 2022 at 01:16 PM, Brooke Clarke wrote:
Self capacity is a very important factor.? Hence the
experiments related to TPI.? But for me it's hard to make sense
of TPI.? So mentioning the physical wire diameter, or the
equivalent the maximum TPI for a close would coil, would help.
?The wire I used 660/46 litz wire, it is 0.065" in diameter,
meaning 8 TPI with be very close to 1 wire spacing. Close wire
spacing is just over 15 TPI.
EBAY Litz supplier,
The old books I referenced when winding AM broadcast
coils talked about a spacing of one wire diameter.? This is easy
to do using a loop of wire with a weight.? Note any dielectric
material near the coil adds capacity, and for some insulators
even adds resistive loss.
Styrene is high on the list of low loss materials. I would have
liked to made the walls of the coupler much thinner, but I had
someone volunteering the work, 5 coils, 5 different threads, so I
didn't ask him to remove a lot of material. I also made the the
thread cut just the minimum, so the wire wasn't surrounded by
styrene.
Getting the minimum wire length for a given single
layer cylindrical coil inductance, like the ones shown in recent
posts, depends on the form factor.? AFAICR making the diameter
about 2.5 times the length is near optimum.? That's to say for a
6" diameter form the coil length should be about 2.4" long.?
The 2.5 ratio was not what my experiment came up with, My test
showed 1.97. The Litz man's page shows a test of a 1.9 ratio coil
with a peak Q of 1472 (805kHz), but he adds, 2.46 is the best
ratio. I don't know if that would hold up over all diameter coils.
???????????????????????????????????????? Mikek
