From: Paul
Date: Mon, 28 Aug 2000 23:38:39 +0100
Subject: [TSSP] More result comparisons in
Results on: BIG LTR Coil No toroid
http://63.225.104.218/test/TeslaCoils/MyCoils/BigCoil/BigCoil.htm
More results from Terry Fritz for his big coil, same setup
as reported yesterday, except without the toroid this time,
makes for an interesting comparison of the two.
Using the measured in-situ inductance, 74.1mH,
Measured Model Error
148.37 152.4 +2.7%
353.40 359.2 +1.6%
513.84 515.7 +0.4%
A little on the high side, as with the two other sets of readings
on coils without toroids. A trend showing up here.
Input impedance (fiddle factor W set at 1.0):
Measured Model Error
f1 784 ohms 320 ohms -59%
and the Q factor predicted is around 70. Was predicted 57
with toroid fitted.
Compare the input impedance with toroid, to that without:
Measured Model Error
f1 408 ohms 368 ohms -10% With toroid.
f1 784 ohms 321 ohms -59% Without toroid.
The rise in f1 input impedance of almost a factor of two when the
toroid is fitted is very similar to that seen in my own coils,
which confirms there is something drastically wrong with the
series resistance estimation. Its such a gross error that
I feel there's a major silly bug in the code - I'm looking
into it. Terry has offered to measure the Q factors for these
two configurations so that will make a total of 7 assorted Zin
and Q measurements on 3 coils which will need to be simultaneously
satisfied by any fix to the Rs estimate. That should be enough
to work with.
Discrepancies:
More glitches in the external cap matrix, laplace
solver problem.
The program calculates Medhurst C to be 15.3pF, and Medhurst
tables give 15.6pF. Once again Medhurst tables work fine
when no toroid is fitted. Note that 12pF of the Medhurst
15.3pF comes from external cap, only 3.3pF from the internal
capacitance. A set of measurements on a coil suspended well
off the ground would help to clarify this.
Data:
See http://www.abelian.demon.co.uk/tssp-data/tfltr/
Files are (in CSV format for Terry running windows):
tfltr.internal-caps.csv: internal caps matrix, pF, 32 segments
tfltr.external-caps.csv: external caps matrix, pF, 32 segments
tfltr.vi152400.csv: VI records at f1.
tfltr.vi152400.gif: VI plot at f1.
General info:
simulator version: v0.2d, 28th August 2000
system: tfltr
LCR Sections 1000, Capacitance segments 32
Coil turns: 1000, resistance: 69.87
Coil radius: 0.130, length: 0.762
Conductor radius: 0.255 mm
Spacing ratio: 0.670
Top loading capacitance: 0.10pF
Weighted internal toroid cap to coil: 0.00pF
Weighted external coil cap to gnd: 12.04pF
Weighted internal coil cap: 3.29pF
Medhurst C should be: 15.33pF
Standard Ln: 1.075uH
Quoted inductance: 74.10mH
Lundin inductance: 76.45mH
using quoted inductance
chose sigma for Mpt: 1345.91
mid coil turn: 79.86uH
end coil turn: 41.10uH
--
Paul Nicholson,
Manchester, UK.
--
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.