IEEE Power & Energy Magazine - January/February 2017 - 72

history

Thomas J. Blalock

reactors for the Roxy
evolution of ac stage lighting

THE INTRODUCTION OF aC sERvices to the "theater districts" of large
cities during the early 20th century allowed for the adoption of reactancetype dimmers to control incandescent
stage lighting, in place of the hopelessly
inefficient resistance dimmers (rheostats) that previously had to be used with
dc services. Then, in a relatively short
time, reactance dimmers were combined
with vacuum tubes to create the first truly
electronic type of lamp dimmer, which
allowed for a much greater flexibility of
control that was not improved upon until
the introduction of computer-type stage
lighting consoles during the latter part of
the century.

The Roxy Theatre
The grandiose Roxy Theatre was located at 7th avenue and 50th street in
Manhattan, New York. It opened in
March 1927 and was the inspiration
of theatrical impresario, samuel L.
("Roxy") Rothafel. The building was
constructed by developer Irwin Chanin,
who had built six other Broadway
theaters as well as the Chanin Building, which is still standing at Lexington avenue and 42nd street. The fantastic Roxy Theatre was demolished
in 1960.
The stage lighting reactance-type
dimmer board for the Roxy was constructed by the former Hub Electric Company of Chicago, and it probably was
the largest such board ever built. It was
Digital Object Identifier 10.1109/MPE.2016.2620659
Date of publication: 2 February 2017

ieee power & energy magazine

Since the launch of IEEE Power & Energy Magazine in January 2003, Thomas
J. Blalock has authored 20 articles for the "History" column. His articles have
covered a wide variety of interesting topics on the history of electric power engineering. This article, his 20th, deals with ac theatrical stage lighting, an avocation in which Tom has enjoyed a special interest and has achieved much.
He first became interested in stage lighting and rigging while working backstage during his high school years in Easton, Pennsylvania. He had little time to
pursue his interest while in college and during his early years at work for General Electric (GE) in Pittsfield, Massachusetts.
In the 1970s, Tom joined a local amateur theater group and spent much time
doing stage lighting and other backstage work. The theater group enjoyed the
use of a new facility with a large, fully equipped stage at the local community
college. Following the closure of the GE plant in 1987, Tom ran that theater
until 1999. During that time, his interest in stage lighting was rekindled with
particular emphasis on the history of theatrical lighting during the 20th century.
As to Tom's educational and career background, he earned a B.S.E.E. degree
from Lafayette College and an M.E.E.E. degree from Rensselaer Polytechnic Institute. His duties as a development engineer at the former GE High-Voltage Engineering Laboratory and later as a test engineer in the Transformer Test Department, both in Pittsfield, included a broad range of activities, including lightning
protection and high-voltage switching surge studies. Since retiring from GE, Tom
has actively pursued his hobby of "industrial archaeology," with particular emphasis on the exploration, preservation, and careful documentation of historically important and interesting electric power projects and equipment.
We are honored to welcome Tom back as our guest history author for this
issue of IEEE Power & Energy Magazine.
-Carl Sulzberger
Associate Editor, History

22 ft (6.7 m) in length and contained
hundreds of individual control levers.
It was installed in a separate room
off stage that was open ended so that
the operators (it took more than one
1540-7977/17©2017IEEE

to run it) had a view of the stage itself
(see Figure 1).
a very early attempt to use simple
series-connected reactors as theatrical
dimmers was a failure. This occurred
january/february 2017

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