Jim,
You wrote>>"
The likely output will be 10KVA based on the core. I have both a .125"
electrode x 12, and a .5" really beefy x 8 rotaries. Richie suggests paying
attention to the dwell time to avoid streaming power arcs. I guess that will
be tested "empirically" (I have lots of cut .125" electrodes for destructive
testing) and 3/8" for dual series fixed.
If I have read this correct, (ignore me otherwise), but are you planning on
putting 10kva through 0.125 inch electrodes? Albeit for destructive testing.
Even 0.125 Tungsten will melt so easily @ 10kva, that you will be hindered
by forever adjusting the gap, combined with power arching from the
overheating electrode surfaces.
use 3/8 Tungsten/copper alloy for the fixed, and 0.25 inch Tungsten for the
rotating, with their lower wear rate and that's only around 6kw.
>>" I haven't made the .5" towers yet, I'm thinking 9/16"
So much depends on the coil, but heat is the enemy. I even use 1 inch
diameter plain copper bar (7 inch tall) so the uprights can act as a heat
sink.
Phil
-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of Jim Mora
Sent: 12 July 2014 02:29
To: 'Tesla Coil Mailing List'
Subject: [TCML] Findinding the facts of a 3 P unknown transformer 50:1
"black Box" and Charging inductor(s) design.
Hello List,
I have been fascinated by 3 Phase, 6 pulse resonance changing since I first
read Richie Burnett's pages 11 years ago. Bert Hickman has been very helpful
in calculating the parameters of my repurposed charge transformer.
Important things to know are the cross-sectional area of the core of coarse
(known).
The turns ratio (approx determined).
Another thread suggests measuring the inductance of a primary winding
(shorted in) and its DC resistance (Z) - good idea!
I have learned a lot from this exercise. My core cross section area is bit
disappointing. But on the other hand, I don't have enough room for very long
streamers but hot ones would be awesome. Bert had an excellent suggestion to
rewire the secondary from wye to Delta which he points out has a 58% drop in
voltage and a bonus substantial output charging current increase.
The likely output will be 10KVA based on the core. I have both a .125"
electrode x 12, and a .5" really beefy x 8 rotaries. Richie suggests paying
attention to the dwell time to avoid streaming power arcs. I guess that will
be tested "empirically" (I have lots of cut .125" electrodes for distructive
testing) and 3/8" for dual series fixed. I haven't made the .5" towers yet,
I'm thinking 9/16"
*** I now want to turn attention to the charging coil ***
My parameters are not too different as Richie's test case. I have a new .1
uf (50KV)General Atomics that can be series to .05 (100KV). I think having
(2) inductors is a good thing for voltage stand off and flexibility and a
variable gap too.
*** I am going to study the many inductor design sites but any school of
hard knocks would be welcomed. I have quite a bit of core material around
both EI and C cores for low freq operation.
*** I fully intend to over build the diode strings but will start a new
thread on the Dequeing diode robustness. I have (500) UF5804 which are
milspec 3 amp 1000v pk inverse diodes, 500 RMS. I intend to over build
beyond that. 3 amps forward(1.5) "should" be plenty for three phase 6 pulse
current at 10KVA.
Thanks for all you do! I am having fun getting back in Tesla coiling!
Jim Mora
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