The works below are the opinion of the author and not the official viewpoint
of the Edison Tech Center:
Lamp Development: A comprehensive history covering the 1930s and 1940s by Rick DeLair
George Inman and Richared Thayer R& D Engineers: William L. Enfield and Philip P. Pritchard Application Engineer: Ward Harrison
OF NOTE: In January 1931 (Jan 27, '31 to be exact) Dr. Albert
W. Hull of the GE Schenectady labs, obtains a paten for low pressure
vapor-discharge lamps - this is a big step towards the development of
fluorescent lamps in coming years
1934: Dr. Arthur H. Compton, on a visit to Oxford, England writes
a letter to Dr. William L. Enfield telling him of the English lamp makers
showed him an interese4ting experimental lamp. It was tubular, about
2 feet long, and the center portion was coated with fluorescent material.
It emitted a yellowish-green light, and appeared to be highly efficient.
In November 1934 research begins at NELA Park. Under management of Dr.
William Enfield, George Inman started development work. Also in the
group were Richard Thayer, Eugene Lemmers, Dr. Willard A. Roberts. In
December, the group made their first lamp. It was 10 inches long, ¾
inch in diameter, and had an electrode in each end. The group made lamps
that used various phosphors, including zinc silicate.
1934-35: Dr. Clifton G. Found joins the R and D Group. Dr. Willard
Roberts, a chemist develops phosphors - aided by Dr. G.R. Fonda and
C. A. Nickel of Schenectady, and Harry M. Fernberdger of the Wire Division.
In the first few years of fluorescent lamp production the most important
phosphors were zinc-beryllium silicate and magnesium tungstate ("white"
and "daylight" lamps, respectively).
In July 1935, Lamp department engineers and research men held
a closed meeting at NELA Park with a group of U.S. Navy officers. Sample
fluorescent lamps were displayed, and the Navy men were the first persons
outside GE to see the new lamps. In early September 1935 the illuminating
engineering society (I.E.S.) held its annual convention oat Cincinnati,
Ohio. GE's exhibit booth showed one of the new "F" lamps in
operation. The lighting engineers attending were interested, but not
overwhelmingly impressed. The lamp looked like a highly specialized
item. It was 2 ft long, produced a brilliant green light. A display
card read: "The fluorescent lumiline lamp - a laboratory development
of great promise." This statement on that card was a REAL UNDERSTATEMENT
- INDEED, for in only about 6 years, a war and a new light source will
transform the USA and soon the World!
1936-1937: In July, 1936 machinery to produce fluorescent lamps
is beginning development with Philip J. Pritchard in charge. Meanwhile
other departments of GE aided in construction of ballasts, starters
(incorporated in the same case as the ballast at first), and lamp sockets
for F lamps. The Transformer Engineering Department in Fort Wayne, Indiana
On November 23, 1936, a dinner held in Washington DC celebrating
the 100th anniversary of the founding of the U.S. Patent Office was
doubly historic. The guests attending the dinner were seeing for the
first time a practical public application of fluorescent lighting. The
new lamps, furnished by GE, provided much of the lighting in the large
More than a year passed, it was late 1937, and P.J. Pritchard and his
colleagues were making progress, but no factory could take on fluorescent
lamp production yet. Very soon this would change!
1938: On April 21, 1938, GE announced the introduction of fluorescent
MAZDA lamps as a regular line and they were placed on public sale. A
story in the Magazine of light appeared at the same time stating that
"These new light sources provide colored light at efficiencies
therefore unobtainable." Lighting would be changed forever, and
for the better! 1938: The new MAZDA 'F' lamps are available in 3 sizes as follows:
15 W, 18 inches long, 1 in. in diameter ('T-12'), and 30 W, 36 inches
long, 1 in. in diameter ('T-8'). They come in 7 colors, 2 of which are
The colors are as follows: Red, Gold (yellow), Green, Blue, Pink, White
(3500 deg. K), and Daylight (6500 K). 3 types of "auxiliaries"
or ballasts, to operate F lamps were available in 1938. The "magnetic
Auxiliary" ballast, which was simple choke reactor type ballast
combined with a "doorbell buzzer-magnetic 'vibrator'-relay starter
unit" in the same case. The next type of ballast was the "Thermal
Auxiliary" which walls had a choke reactor type ballast combined
with a "doorbell buzzer-magnetic 'vibrator'-relay starter unit"
in the same case.
type of ballast was the "Thermal Auxiliary" which also had
a choke-reactor ballast combined with a thermal-switch-relay starter
unit in the same case. The last type, still made today, was then called
a "Manual Start Auxiliary" and was merely a choke ballast
for use with manual starting switches. The 15 and 20 W ballasts were
110 to 120 volts. The 30 W ballasts were 220-240 volts, and required
step-up transformers installed in the fixtures if the 220 volts needed
was not supplied and only 110 volts was available to the fixtures.
In the summer of 1938, Westinghouse Electric Corporation invents
the glow-switch type of starter. Initially in an S-6 bulb with bayonet
base, it fit into a socket on the end of the ballast case. The familiar
"can" twist -in glow switch starter didn't appear until mid-summer
1938: A little later in this year, the 14 W, 15 inch 1-1/2"
(T-12) MAZDA lamp is introduced. Initially intended for use on a 64-volt
street rail car, it soon was used 2 in series on 120 volts with a 60
volt ½ amp incandescent MAZDA lamp as a ballast, in floor and
table lamps, it also operated on 15 watt ballasts as well.
Germicidal lamps ware introduced. Clear, with no phosphors, and made
of U.V. transmitting "corex-D" glass, they emit short-wave
ultraviolet (U.V.) rays that kill airborne bacteria. The lamp was made
in 15 W and 30 W T-8 tubes then. Westinghouse developed the principals
prior to 1936.
In late spring of 1938, fluorescent lamps were shown at the New York
World's Fair and the Golden Gate Exposition in San Francisco, CA. The
lamps were used outdoors at the world's fairs and a large indoor installation
at the New York Exposition.
Fluorescent lighting was now officially launched. In October 1941 a
patent was granted to George Inman covering the basic principals of
fluorescent lamp design. The application was filed in April 1936.
During 1938 form April on, GE and the whole industry sold about 200,000
lamps, good for the first year, but nothing compared with what was soon
The 40 W lamp (white color) was rated at 35 lumens per watt early on,
and before mid-year it had reached 47 lumens per watt(lpw), and by years
end it reached 50 lpw.
Sales of fluorescent lamps rocketed to 1.6 million in 1939.
GE develops the RF, or Rectified Fluorescent lamp for industrial lighting
early in the year. It was 8.5 watts, 58 inches long, 1-1/4 inches in
diameter (T-10), and was 47 lpw and rated at 3000 hours. It had one
heated cathode at one end, like standard F lamps, and 2 unheated anodes
at the other end. Current flowed in only one direction, thought the
lamp, going to the 2 anodes alternately as the A.C. line current changed
direction 60 times a second (120 reversals/sec.) making the RF lamp
a "full-wave mercury-arc rectifier." It used special bases
and sockets, with 3 prongs on the anode end, 2 prongs on the cathode
end, and special ballast. It needed no starter either. It was not made
after 1942 anymore.
Hygrade -Sylvania develops "stroboscopic-corrected" lead-lag
ballast circuits, and introduces the first fixture to use it - the 2-lamp,
4 ft "HF-100" unit for industrial use. This had 2 choke ballasts,
a step-up transformer, a starting compensator for the "leading"
lamp, and a capacitor for this same compensator for the "leading"
lamp, and a capacitor for this same lamp, all separate units! I have
one, made circa May 1939, serial no. 8108 with rare original thermal-switch
starters - working!
1939: Early in this year (around Feb-March) GE introduced the
now ubiquitous 48 inch (4 ft) 1-1/2 in. Diameter T-12, 40 watt MAZDA
F lamp. Initially there was much skepticism among GE engineers that
such a long lamp was not practical or even possible to manufacture.
Again GE accomplished the "impossible"! Like the 30 watt lamp,
this new lamp at first used 240 volt choke ballast and a step-up transformer
if used on a 120 v circuit. This size quickly became and remains to
this day, the most popular fluorescent lamp ever made! Even today's
4 foot T-8 F lamps aren't at all "high tech" and were made
experimentally in 1939!
This article goes on in depth until 1957. See the full article at
the Edison Tech Center.
featuring the earlier inventors of the lamp:
on the graphic below to see our full page on fluorescent
lamps including early history.
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