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Re: 1939 Worlds Fair GE Exhibits
Original poster: "Mike" <mike.marcum@xxxxxxxxxxxx>
Wonder how far they could have got it to spread
if it was set up as the usual V (or 3D W with
3-phase)? Looks like the spinning actually caused
the arc to break early. Assuming 10kVA per yard
1000kVA could have made 300-footers. Guess they
ran out of money after buying the equipment and
didn't have funds for a bigger building to house it.
Mike
----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Saturday, October 21, 2006 3:48 PM
Subject: Re: 1939 Worlds Fair GE Exhibits
Original poster: Bert Hickman <bert.hickman@xxxxxxxxxx>
Curt, Ben, and all,
Curt - thanks for the excellent pictures! And
Ben, we'd love to see a scan of the picture you
have. Following is a portion of my posting about
the GE World Fair exhibit from last June on the HV List:
For the 1939 World's Fair, GE used twin 5 MV bipolar Marx generators to
develop 10 MV discharges that spanned 30 feet. This really must have
been an incredible sight to see (and hear!). Following is some
information from the October, 1939 issue of "GE
Review" magazine about the twin Marx generator,
the 3-phase arc, and some subsequent history.
I've also included some links to some B&W pictures.
Each 5,000,000 volt Marx generator used 51 0.33 uF 100,000 volt Pyranol
capacitors, and each stage consisted of three capacitors connected
in series. Each generator was charged from a bipolar 300,000 volt DC
source (+/- 150 kV on either side of ground) which used high voltage
vacuum tube rectifiers ("Kenotrons"). The effective series capacitance
of each 5 MV unit was 0.00653 uF, for a stored energy of 81.6
kJ/generator or ~163 kJ during a 10 MV discharge. Following are some
images of the facility (you can get a feel for the scale in the first
picture):
http://205.243.100.155/photos/GE_Lab/10Mev2.jpg
http://205.243.100.155/photos/GE_Lab/10Mev1.jpg
http://205.243.100.155/photos/GE_Lab/Steinmtz.jpg
http://205.243.100.155/photos/GE_Lab/impulse.jpg
http://205.243.100.155/photos/GE_Lab/ltning.jpg
The million volt 3-phase arc was powered from a 1500 hp motor-generator
set, and used reactive current limiting. Open circuit voltage across
phases ranged from 850 kV to 1 MV. Six 350,000 volt cascade transformers
were used, each with a rating of 1,000 KVA, with pairs connected in
series-cascade to generate 700,000 volts to ground or about 1.2 MV
phase-to-phase. The grounded (bottom-most) transformers each had a
tertiary 2300 volt winding which drove the LV side of the floating
transformer.
Each floating transformer sat on a 5 foot high insulating pedestal and
operated at 350,000 volts above ground. The diameter of each transformer
was 85.5" and overall transformer height including insulator was 14 feet
10.5". The transformers were designed to harmlessly arc over the output
bushing at 450,000 volts and to safely withstand transient impulses of
over 1.3 MV. Images of one of these transformers undergoing 450 kV
dielectric and 1.3 MV impulse testing follow, and I've also included an
image of a single-phase million volt arc:
http://205.243.100.155/photos/GE_Lab/XfrmrArc.jpg
http://205.243.100.155/photos/GE_Lab/1mevarc.jpg
Electrodes for the three phase arc were mounted on 18 foot insulating
masts, and the masts were arranged to form an equilateral triangle 14
feet on a side. Each electrode consisted of a spinner electrode (a bar
mounted on ball bearings and tipped with 5" balls on the end. Tangential
to each ball was a sharp pointed half tube that held a colored fusee
which served to color the arc as well as increase its length. Corona
drove the spinners like giant pinwheels at 50-100 RPM depending upon the
length of the spinner. Two interchangeable length spinners (3 foot and 5
foot) were used. The minimum distance between spinners was between 9 and
11 feet depending upon the length of the spinner that was used. Once
ignited, the arc rises 20 feet above the gap in a tortuous path
estimated to be between 100-150 feet long.
Unfortunately, I haven't had any success in locating good pictures of
the spinning 3-phase arc. One picture (unfortunately very small) of a
static arc can be seen here:
http://205.243.100.155/photos/GE_Lab/3-Phase_Arc.jpeg
At the conclusion of the World's Fair in 1940, the HV transformers and
Marx generators were transported back to GE's HV Lab in Pittsfield,
MA. These were then used to build two larger impulse generators in a
new High Voltage Laboratory in 1949. The rebuilt Marx generators could
develop up to 15 MV (+7.5 and -7.5 MV versus ground), and could flash
across a 50 foot gap (the previous generator could "only" do 30 feet). A
picture of the newer 15 MV system (and a good view of the last two
stages of a a triple cascade transformer setup) can be seen at from this
article in National Geographic, June 1950, "Lightning in Action":
http://205.243.100.155/photos/GE-Lab/15MV_Discharge.pdf
The complete article can be found here:
http://www.usfcam.usf.edu/McCollumPDF/14.Colton.pdf
The Pittsfield facility finally closed its doors in 1995. GE's
Pittsfield manufacturing facilities are undergoing cleanup due to
PCB contamination from earlier electrical and chemical manufacturing
operations. Some of the equipment that was in the Pittsfield HV lab was
ultimately transferred to a smaller HV lab in Fort Edward, New York. I
don't know if this included the 350,000 volt transformers, since they
would have been over 55 years old by then...
BTW, those of us who are old enough to remember the "General Electric
Theater" on TV in the '50's and early 60's (hosted by Ronald Reagan!)
may also remember that GE began the show with about a 2 second video
clip of the million volt arc... :^)
Best regards,
Bert
Tesla list wrote:
Original poster: Ben McMillen <spoonman534@xxxxxxxxx>
These are amazing..
I *think* I have an original black-and-white
that was taken of the exhibit.. I remember
asking about it on the list a few years ago to
see if anyone else could tell me what it was..
The photo is nearly identical to photo 089 (near
the bottom of the page) with the GE logo visible
in the back.. I'll have to see if I can find it (if anyone's interested)..
Coiling In Pittsburgh
- Ben McMillen
Tesla list <tesla@xxxxxxxxxx> wrote:
Original poster: "resonance"
G.E. had a huge Marx impulse lightning generator there. It produced
+5 million and -5 million Volts, so 10 million between the two 70 ft.
tall towers. My grandfather said it was so loud you could barely
stand to hear it fire.
They also have a 1 million Volt xmfr setup with AC power arcing
between xmfrs. A large series reactor controlled the current on each pri.
Dr. Resonance
>I came across the following searching for information regarding a
>Tesla coil my Dad says he saw at the 1939 world fair. I didn't find
>the Tesla coil, but found what looks like a jacob's ladder with
>rotating electrodes. Not specifically Tesla related, but thought the
>group would enjoy:
>
>Still pictures:
>http://www.pmphoto.to/WorldsFairTour/Zone-5/090.htm
>
>Video:
>http://www.archive.org/details/Medicusc1939_3
>
>It's a fascinating display, looks like it might be three phases
>arcing together? No sure what to make of it.
>
>If anyone has any detail of a Dr. Moon at the fair, please let me
>know. Apparently he would stand on the top of his coil and let the
>streamers come from his fingers.
>
>Curt.
>
>
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