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THOMAS W. DAKIN
1 915-1 990
BY LEE A. KILGORE
TOM DAKIN, world-renownec3 specialist on insulation for elec-
tric machinery, cried April 1, 1990. He was born in Minneapolis
on May 5, 1915. After graduating from the University of Minne-
sota, he received a Ph.D. in physical chemistry in 1941 from
Harvard.
He made his careerwith the Research Department of Westing-
house Electric. From 1946 he directed the company's electrical
insulation development, making many individual contributions.
In 1948 he proposed a methodwherebyinsulation deterioration
with aging at elevated temperatures could be treated as a chem-
ical rate phenomenon in accordance with the Arrhenius equa-
tion. This method iswidely used because it has more validity than
other methods that have been proposed and because of its
. . .. .
re Steve simplicity.
He pioneered investigations into the effects of electric dis-
charges on the breakdown of solict insulation, a method of
estimating the magnitude of internal electric discharges and
dischargingvoid volume in high-voltage apparatus by measuring
capacitance increase with increasingly high voltages. He con-
firmed and applied the concept that alternating-currant voltage
endurance (useful life of insulation uncler voltage stress) is
proportional to the number of cycles applied. Bushings for high-
voltage applications are made with cycloaliphatic epoxy resins.
Under his guidance, cycloaliphatic epoxy bushings have been
57
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58
MEMORIAL TRIBUTES
field tested in contaminated atmospheres under high-voltage
stress for more than eightyears with excellent results. In addition
to field testing, weathering stations were established in areas that
were typical of the types of environment bushings might encoun-
ter in service. He devised a laboratory-accelerated test that
appears to duplicate, in less than aweek, ayear of exposure in the
weathering stations. He investigates! the voltage endurance of
cast epoxy resins with microcavity type defects. The study indicat-
ed that care must be exercised so as not to apply too high an
average voltage stress to cast epoxy insulators, even when no
internal corona can be detected.
He was a major contributor over a period of many years in the
field of power capacitor development. A key to the dramatic
progress maple in size and cost reduction per kilovolt-ampere
was, again, the clevelopment of an accelerated life test based on
power factor increases with time at several temperatures. These
studies, which permitted the selection of the best low-Ioss mate-
rials, were carried outwith the paper-askare} and polypropylene-
paper-askare} systems, and also the latter where the askare} was
replaced by liquicls free of polychIorinatecl biphenyls (e.g.,
isopropy~biphenyI).
A fellow of the Institute of Electrical and Electronics Engi-
neers (IEEE), he received IEEE's Electrical Insulation Society
Award for Technical Achievement in 1978 and its Westinghouse
Order of Merit and Lamme Meclal. He served on the National
Research Council's Conference on Electrical Insulation and
Dielectric Phenomena and was the U.S. representative to the
International Conference on High Voltage Electric Systems
(chairman of the Committee on Solic! Insulation). He was
elected a member of the National Academy of Engineering in
1981.
Dr. Dakin was active in civic affairs, serving for many years as
secretary of the local School Building Authority, and he was an
active member of the local Rotary Club. His wife Theo(lora was
a meclical doctor, and they were known among friends as Dr.
Tom en cl Dr. Ted.
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Representative terms from entire chapter:
voltage stress
