Hi Stefan,
My newest gap is 5/8" G10/fr4 (15.875mm) and was designed to run a Pig coil,
not knowing the outcome of the resonance charging project. I do have a 1/2"
(12.7) G10 that is set up for 12 electrodes (with a larger diameter also
good) which could be repurposed to 6. Max size of W would be 3/8" (9.25) as
made. And yes, the conservation of energy on .5" (12.7) tungsten spun up is
a bit disconcerting! Our craft is dangerous. I have always paid attention to
potential electrical shock hazards. And respect the energy of spinning
Tungsten. That did not preclude potential energy converted to kinetic energy
of mass and having my 200LB (90.7 kg) transformer from falling on my leg and
breaking it ;-^) F=MA I wonder if that is in the safety chapter on
Pupman.com - stupidity on my part.
My gap is more patterned after Bill Wysock's classic design. It is not hard
to find 14400V and up transformers in the US; but, the Burnett site has
intrigued me. (credit is stated from work mostly of Bert Hickman and Greg
Leyh) and Burnett's own experience in the field of power electronics.
It sounds as you are making real progress. The RPM counter is cool!
Did you make or have made your former on the resonance transformer? I have a
core similar to that. Actually, mine would be a three phase with the center
core removed. It has already been de-interlaced.
I do like the simplicity of rectified Ac and a variac powering a DC motor.
PWM controls torque and speed better though, but is again subject to hash
and transients. I think the AC motor is more suited to synchronous AC
operation or high speed operation.
I look forward to your thread on the rotary and I would like to know more
about your inductor!
Jim Mora
-----Original Message-----
From: Tesla [mailto:tesla-bounces@xxxxxxxxxx] On Behalf Of Teslalabor
Sent: Tuesday, August 19, 2014 7:08 AM
To: Tesla Coil Mailing List
Subject: Re: [TCML] was RE: How I modified the 3 phase for dual wye 5KV
2xI;** Now charging inductors.
Hi Jim,
my new rotary for the DC resonant charger is nearly completed. The mechanic
part works already (which was a real challenge to get a 25cm diameter G10
disk with 6 tungsten rods spinning up to 4000rpm (=400bps) with no dangerous
vibrations). It seems, that even speeds up to 6000rpm (=600bps) should be
possible without any problems, but will test this later :-) By the way, at
4000rpm, the "weight" of each electrode which weights only 42,7g rises up to
arround 87kg! :-)
After completing it with the stationary electrodes, I will start a thread
about it and present it to all of you. One of the cool things on my new
rotary is, it even has a tacho generator on it's shaft + rpm-meter (which
will be integrated in the control box later), so I have real time
measurement of the rpm's (and bps). I'm using only 6 rotary electrodes,
which gives me a nice low dwell time, even at reduced speed, so very low bps
should be possible without igniting a power arc travelling arround the disk
:-) Jim, maybe you should also think about this: Use only 6 instead of 8
electrodes and increase your disk speed.
My rotary is driven by a 230V AC/DC 450W Motor which has a max speed of
12500rpm. The speed is controlled with a simple variac. By the way, I never
understood, why folks use AC induction motors with a complicated (and
expensive + sensible electronics) variable frequency drive, to control the
speed of spark gaps.
Regards,
Stefan
<snip>
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