Re: GE HV Research (cont.)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Bert Hickman by way of Terry Fritz <twftesla-at-qwest-dot-net>" <bert.hickman-at-aquila-dot-net>

Godfrey and all,

Some more information on the transformers and caps from the October,
1939 issue of the General Electric Review:
Each 5,000,000 volt Marx generator used 51 0.33 uF 100,000 volt Pyranol
capacitors, with each "stage" consisting 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. 

The million volt three 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 low
reactance 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 transformers each had a
tertiary 2300 volt winding which drove the LV side of the floating
transformers. 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 insulator at 450,000 volts and to safely
withstand transient impulses of over 1.3 MV. Pictures of one of these
transformers undergoing 450 kV dielectric and 1.3 MV impulse testing can
be seen at:
http://www.aquila-dot-net/berthickman/photos/XfrmrArc.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. 
   
At the conclusion of the World's Fair in 1940, these transformers and
the 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 new 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
National Geographic, June 1950, "Lightning in Action":
http://www.aquila-dot-net/berthickman/photos/15MV_Discharge.pdf

The Pittsfield facility finally closed its doors in 1995. GE's
Pittsfield manufacturing facilities are now 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. Some additional information about
Pittsfield, including another view of the 3-phase arc, can be seen at:
http://www.platts-dot-com/engineering/issues/ElectricalWorld/0103/0103ew-arc.sht
ml#top

Best regards,

-- Bert --
-- 
Bert Hickman
Stoneridge Engineering
"Electromagically" Shrunken Coins!
http://www.teslamania-dot-com

Tesla list wrote:
> 
> Original poster: "Loudner, Godfrey by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <gloudner-at-SINTE.EDU>
> 
> Hi Bert
> 
> What do you suppose ever happened to these huge transformers?
> 
> Godfrey Loudner
> 
>         -----Original Message-----
>         From:   Tesla list [SMTP:tesla-at-pupman-dot-com]
>         Sent:   Friday, July 19, 2002 12:46 PM
>         To:     tesla-at-pupman-dot-com
>         Subject:        Re: GE HV Research
> 
>         Original poster: "Bert Hickman by way of Terry Fritz
> <twftesla-at-qwest-dot-net <mailto:twftesla-at-qwest-dot-net> >" <bert.hickman-at-aquila-dot-net
> <mailto:bert.hickman-at-aquila-dot-net> >
> 
>         It's probably a shot of a power arc from a pair of 350 kV HV test
> transformers (seen on either side).
>