IEEE Power & Energy Magazine - January/February 2017 - 79

panel. GE also manufactured resistance
dimmers, but these usually were separately mounted above the board itself.
These switchboards were constructed
exactly the same as industrial switchboards of that era that were manufactured by GE at its schenectady, New
York, plant.
such a stage switchboard still exists (but not in use) in the lobby of the
restored Colonial Theatre in Pittsfield,
Massachusetts. The board dates from
1912 and was refurbished for display
along with the restoration of the theater.
Both the board and the dimmers still
display GE nameplates.
In the mid-1920s, GE acquired
the Trumbull Electric Manufacturing Company of Plainville, Connecticut,
which manufactured auto-transformer
dimmer boards for stage lighting control. The auto-transformer was a logical device to adapt for use as a stage
lighting dimmer. It was simple and
rugged and did not require an auxiliary source of dc for its operation as
with the saturable core reactor dimmer.
It was, however, still quite large and
heavy due to the need for a laminated
steel core.
as a result of the work of albert Hull,
GE held the early patents on the thyratron tube. Consequently, GE decided to
enter into the development of thyratronreactor dimmers. significant early development work also had occurred at
the schenectady GE plant regarding the
use of saturable core reactors for various
industrial control applications.
The early development of thyratronreactor dimmers was carried out at the
schenectady plant by research engineers allen Bailey and Harold LaRoque
and, later, by Dudley Chambers and
Elbert schneider. all four eventually
received patents for their contributions.
Ultimately, GE only made ten installations of thyratron-reactor lighting control in theaters, during the late 1920s
and through the mid-1930s. The first
such installation was for the Chicago
Civic Opera House in 1929. This was a
relatively simple two-scene preset board
controlling 140 dimmers and having a
total load capacity of 1,250 kW.
january/february 2017

of the possibility of having the control
board located in the auditorium, and,
instead, it was installed backstage just
as the earlier manual-type boards had
been. The reason for this is not known
(see Figure 3).
The Palace Theatre still exists and is
still in use today but the thyratron-reactor

In 1931, GE installed a very modest
nine-dimmer thyratron-reactor board at
the new Plaza Theatre in schenectady (demolished in 1964). In that same
year, a more significant 48-dimmer
installation was made at the new Palace Theatre in albany, New York. In
this case, the advantage was not taken

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Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - January/February 2017