Warren_master_clock.png
Summary
Description Warren master clock.png |
English:
Electric utility
master clock
invented by
Henry Ellis Warren
in 1916 and manufactured by his company
Warren Telechron
. These were installed in the control rooms of U.S. electric generating plants and were the first device to precisely control the daily frequency of electric power grids. Warren promoted these to electric utilities in order to stabilize the power grid frequency to make the synchronous electric clocks his firm produced accurate. By 1935 Warren master clocks regulated over 95% of the electric power in the U.S.
The device consists of a precision pendulum clock with a low temperature coefficient
invar
pendulum rod, and a synchronous electric clock driven by the 60 Hz electric power from the plant. The pendulum clock turns a black hand on the center dial, and the electric clock turns a gold hand on the same dial. The plant operator would adjust the output power until the two hands turned in synchronism. If the gold hand fell behind, the operator would increase power so the generators turned slightly faster, increasing the frequency of the alternating current, causing the electric clock to run faster until the gold hand caught up to the black one. If the gold hand got ahead, he would reduce power. This kept the averaged frequency of the AC power at exactly 60 Hz. The result was that all synchronous clocks attached to the power grid would keep in step with the precision pendulum clock, which was accurate to within a few seconds per week.
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Date | |
Source | Downloaded 2012-08-12 from Henry E. Warren (May 7, 1919) 'Using the time characteristics of alternating current', Trans. of Amer. Inst. of Elec. Eng. , Vol. 38, Part 1, p. 772, Plate 35, Fig. 3 on Google Books |
Author | Henry Ellis Warren |
Licensing
Public domain Public domain false false |
This media file is in the
public domain
in the
United States
. This applies to U.S. works where the copyright has expired, often because its first
publication
occurred prior to January 1, 1929, and if not then due to lack of notice or renewal. See
this page
for further explanation.
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This image might not be in the public domain outside of the United States; this especially applies in the countries and areas that do not apply the
rule of the shorter term
for US works, such as Canada, Mainland China (not Hong Kong or Macao), Germany, Mexico, and Switzerland. The creator and year of publication are essential information and must be provided. See
Wikipedia:Public domain
and
Wikipedia:Copyrights
for more details.
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