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Re: [TCML] Tesla Digest, Vol 147, Issue 3 more info for Chris Reeland <chrisreeland@xxxxxxxxx>

Hi Chris,

I have a few notes add to the research center picture I sent previously:


The 14-sided test chamber is 75 feet across.

The large Marx generator is ~55 feet tall and 85 feet long (5 million volts

One of the 40-inch (1000 mm) calibration spheres (copper is greenish color
now) is visible just below 
the 60-ft portal tower structure over to the right on the concrete pad. The
corona rings and conductor 
tubes were all made from 6" aluminum.

Below the test chamber are the remaining two Allis Chalmers HV transformers 
(the third one has been removed). They were placed on insulating pedestals
the cases could be floated up such that when the full 3-step cascade was
it produced a face value of 2,250 KV at 1800 KVA (750 KV @ 600 KVA each).
They were 
originally energized with a motor-generator set that allowed for field
weakening so the 
output could be boosted by at least 15% (yielding >2.5 million volts rms at
60 Hz).

If you have read Harry Goldman's Volume 3, No. 1 edition of the Tesla Coil 
Builders Association periodical, " T.C.B.A. News" article on A. O. Austin of
Barberton, Ohio, then you 
are familiar with the Ohio Brass Co. (then the Ohio Insulator Co.). These
along with a 2-1/2 million volt hexagonal Marx Generator, and a 15-ft tall
Tesla Coil 
were originally set up at the high voltage research farm at the O. C. Barber
estate east 
of Barberton in the early 1930's. All of these systems were later moved to
the Ohio Insulator 
Co. factory test building just off of 9th St. in Barberton where the TCBA
cover picture was 
composed. In 1968, the three transformers were moved to the new Frank B.
Black Research 
Center in Wadsworth, Ohio where a new 5 million volt Marx generator was
The big Tesla Coil was discontinued in the late 1950's, then salvaged in
1958  from Barberton.  

Dick Hoover
Replying to:
Message: 1
Date: Sun, 16 Feb 2020 20:53:16 -0600
From: Chris Reeland <chrisreeland@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: Re: [TCML] Tesla Digest, Vol 147, Issue 1
Content-Type: text/plain; charset="UTF-8"

Hi Dick,

A last big quote here:
"Back a few years when I was impulse testing UHV insulators, we used the
original Tektronix 507 Dual Beam Oscilloscope. We experienced oscillations
in the input amplifier circuits which appeared as oscillating time (negative
time) during the rise of the voltage rise for each impulse. The fix was to
remove the input amplifiers completely and directly connect the incoming
signal to the vertical plates of the 507 scope. The images were captured
single-trace on high speed Polaroid flatpack film. A pair of 1000 mm
(40-inch) spheres were used to calibrate the total measurement for a
uni-potential pulse from a 5000 kV Marx generator.    

--------- note: be sure that your scope is reading the true risetime of the
voltage waveform!

Rule of thumb - you need at least 1 ft of clearance for every 100 kV (peak)
of arc potential with a nominal 1 kv/uSec rise time. Faster risetime has a
higher breakdown voltage, where slower risetime has a lower breakdown
voltage.  Ref-IEEE-4. "

I want to say just WOW!!! Very big stuff on that compound. I have looked
out of curiosity zooming in and out of the satellite imagine link you
provided. Can see also all kinds of very large interesting things. Looks to
be large corona rings on several things also. Even though I know huge,
still hard to comprehend the full scale of this all.
Really neat. Quite the research compound.

Chris Reeland
Ladd Illinois USA

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