Re: Coil data & wall distances

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi Weazle,

Tesla list wrote:

>Original poster: "J. B. Weazle McCreath by way of Terry Fritz 
><twftesla-at-qwest-dot-net>" <weazle-at-hurontel.on.ca>
>Hi Bart, Coilers,
>
>The only "hard data" that I have is on the MMC, with a calculated
>capacity of 0.026 uF., versus a measured capacity of 0.03 uF. and
>on the Mutual Inductance and K, which I measured using the method
>described by Terry Fritz.  The measured Mut. L was 38.76 uH. and
>the K was 0.1, which are pretty close to what the MandK program
>gave, 38.4 uH. and 0.105 respectively.

Ok, that tells us there are dimensional errors which may be in the 
secondary and/or primary. Fantc in the mutual inductance area "is" ACMI. If 
you use a detail of 2, then you should come up with the same number ACMI 
produces. I've made test measurements for Mark and Paul on both their 
programs at their requests while testing out program accuracy. Many others 
have performed these same tests. Both programs should be very close.

Ok, I just ran MANDK and FANTC on your coil.

MandK gave Lm: 49.694, K: 0.1309
Fantc gave Lm: 49.38, K: 0.139

Note these are much closer than your data identified. For reference on the 
inputs used, I'll show both Fantc and MandK inputs below (should you ever 
see a huge disagreement between these programs, there is "most likely" 
interpretation error of one or more of the inputs). From my input data, you 
should be able to find where the discrepancy is:

Also note, both FANTC and MANDK inputs are identical, they just use 
different styles (and for good reason). Fantc uses radius's and height 
relationships from points of references for capacitive calculations. It's 
still a 22" height coil with the bottom turn at the same height as the 
bottom primary turn.

--------------------
FANTC: (detail 2) - These inputs are required for Mutual Inductance Analysis.
Sec inner radius: 2.05
Sec outer radius: 2.05
Sec bottom height: 30
Sec top height: 52
Sec turns: 800
Sec wire diam.: 0.0253
Pri inner radius: 3.3
Pri outer radius: 6
Pri bottom height: 30
Pri top height: 31
Pri turns: 6
Pri wire diam.: 0.25

Running F A N T C using core functions of G E O T C version: 2.2
Computing ..... please wait
Mutual Inductance (L1,L2): 49.38 uH
Coupling Coefficient(K): 0.139
Run CompleteTime elapsed: 7.3 secs

--------------------
MANDK:
Mutual Inductance Program V3.1
Copyright (c) 1998, 1999, 2000 by Mark S. Rzeszotarski, Ph.D.

Inverted Cone Primary Coil Geometry
Primary coil inside diameter (inches)= 6.6
Primary coil outside diameter (inches)= 12.0
Number of primary coil turns =      6.0
Last turn elevation in inches =      1.0
Wire diameter (inches)=      .25

Solenoidal Secondary Coil Geometry
Secondary coil diameter (inches)= 4.1
Secondary coil height (inches)= 22.0
Number of secondary coil turns = 800
Secondary coil wire diameter (inches)= .0253

Position            M               K
.000          49.694           .1309

Well, that should give you some info on MandK input information to model 
both primary and secondary. I suspect you may have made an interpretation 
error somewhere. I've done that a number of times with about every program. 
Now, if your measurement disagree's with either program, then the programs 
are being fed incorrect dimensions. I guarantee this.

>I don't have a scope or other fancy test gear, so I'm afraid I'll
>not be able to give you any other measured values, especially the
>one about the secondary that you would like to have.  Maybe I can
>borrow the necessary equipment from a Ham friend.

If you don't have the equipment, don't worry about it. I do appreciate your 
data. I do encourage you to go back through some of the measurements. 
Things like primary inner diameter, outer diameter, sec turns, etc.. are 
among the usual areas where there is discrepancy.

Well, better stop.
Take care,
Bart