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Re: ribbon vs. tubing
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|From: "tesla-at-poodle.pupman-dot-com"-at-PMDF-at-PAXMB1
|To: Benson Barry; "Tesla-list-subscribers-at-poodle.pupman-dot-com"-at-PMDF-at-PAXMB1
|Subject: Re: ribbon vs. tubing
|Date: Saturday, December 07, 1996 2:45PM
|
|<<File Attachment: 00000000.TXT>>
|From lod-at-pacbell-dot-net Sat Dec 7 08:43:59 1996
|Date: Fri, 06 Dec 1996 22:45:40 -0800
|From: lod-at-pacbell-dot-net
|To: tesla-at-pupman-dot-com
|Subject: Re: ribbon vs. tubing
|
|Benson_Barry wrote:
|
|
|> I was thinking in terms of the proximity effect.
|> Does not greater self capacity increase the
|> proximity effect of a coil? Thinking of it like
|> a reactance would it not increase the impedance
|> of the primary thereby limiting the di/dt attainable?
|> Barry
|
|
|What's the 'proximity effect'?
|
|-GL
|
The proximity effect is a term used to describe the
skin effect for wires close together such as in a coil.
I think that there might be two effects. The
electromagnetic induction between wires and the
electrostatic induction between wires. The latter is
evinced by the need to space the turns in the primary
to prevent arcing and the arcing up and down the coil
when the voltage gradient becomes too high. The
electromagnetic induction and electrostatic
induction tend to cause the charge to concentrate
near adjacent surfaces. This reduces the effective
diameter of the coil for a solenoid and causes the
inductance to (decrease?). The electrostatic
induction is caused by the potential gradient
across the winding length.
I was wondering if the increased cross section in a strip
winding would not increase the capacity between
adjacent differences of potential in time and in some
way offset the benefits of a strip winding. The only
reference to electrostatic induction that I have been
able to find is on page 142 of "The transmission line
reference book", second edition, 1982 by the
Electric Power Research Institute, prepared by the
General Electric company.
I am also curious about the affect of the increased
surface area of the strip winding upon energy loss
by magnetic diffusion. As the frequency increases
the magnetic flux gets trapped within the conductor
and causes energy loss. I wonder how this affects
the choice in wire size for the secondary also. Is
there an optimun geometry-inductance-wire diameter
for each frequency to achieve minimum energy loss?
Barry
|