Henry Ellis Warren

Background

Henry Ellis Warren was born in Boston, Massachussets, the son of Henry Warren and Adelaide Louise Ellis.

Education

In 1894 he received the B. S. from the Massachusetts Institute of Technology.

Career

After working as an electrical engineer with the Saginaw Valley Traction Company in Michigan, he returned to Boston in 1902 and joined the Lombard Governor Company, where he made a number of inventions, including an improved governor for water-driven turbines. He acquired ownership of the Lombard Governor Company in 1937 and was president from then until his death. Having become interested in local politics, Warren served as an Ashland selectman from 1907 to 1909 and as a member of the Ashland Forestry Commission from 1937 until his death. Sometime before 1914 Warren had become interested in the problem of devising a reliable, accurate electric clock that could be synchronized to the frequency of distributed alternating-current power (60 cycles per second in the United States). His proposal to base such a clock on a synchronous electric motor had been suggested as early as 1895. Warren's contributions were to design a specific mechanism for the purpose and to establish a manufacturing facility to produce it. Warren considered it important that any electric clock be self-starting. To accomplish this, and to ensure that the motor began to revolve in the desired direction, one of the pole pieces was "shaded, " that is, provided with copper rings, in which eddy currents could build up, thereby delaying the growth of the magnetic field. This arrangement allowed the rotor to be brought up to synchronism from rest, while ensuring that it did not slip thereafter. The clock would then keep time as faithfully as the power supply was maintained at 60 cycles per second. In order to manufacture his clock, Warren founded the Warren Clock Company (subsequently renamed Warren Telechron) in 1912. By 1918 it was selling in mass quantities what came to be called the Warren synchronous clock. Electric clocks were not new at this time. In some, the mechanism was directly driven by an electric motor. In others, a pendulum or balance wheel was activated by periodic pulses. There were slave clocks controlled electrically through wiring from a central master clock. Warren's invention made available for the first time an electric clock that was cheap, reliable, and accurate. It also pointed the way toward the use of fractional horsepower motors in self-contained equipment for other domestic uses. The principle of Warren's clock is still in use in electric clocks. Warren's invention and promotion of the synchronous clock led directly to a twenty-year association with the General Electric Company. Prior to the introduction of the synchronous clock, standards of power frequency control were quite lax: several percent variation from nominal was quite common, and there had been little motivation to improve it. (Translated into time, a 1 percent variation in frequency would amount to a clock error of nearly fifteen minutes per day. ) Warren therefore had a decided interest in improving the quality of power frequency control. While aware of the potential profit in Warren's invention, General Electric also realized that improved frequency control would be increasingly important if individual power companies were to be linked in regional distribution networks. In 1919, therefore, General Electric invited Warren to become a consulting engineer. Soon thereafter, he devised a master clock for controlling the power frequency of the generating stations. Thanks to this invention, the power frequency control had by 1939 been substantially improved, with the result that clock errors had been brought down to a second or two per day. General Electric acquired a 50 percent interest in Warren Telechron in 1929 and bought full control fifteen years later. Warren's other inventions included fire control mechanisms and tracking devices for astronomical telescopes. He died in Ashland, Massachussets

Achievements

• He credited with invention of the first synchronous electric clock which kept time from the oscillations of the power grid in 1918 as well as with 134 other inventions. Warren founded Warren Telechron Company in 1912 which later was acquired by General Electric in 1943. Warren was noted as the "father of electric time". Just between 1916 and 1926 the company sold 20 million clocks.

Interests

• Financially secure, Warren later developed a number of other interests, including farming, and ran his house in Ashland as a working dairy farm. He was active in the Boy Scouts and in the Salvation Army.

Connections

On January 19, 1907, he married Edith B. Smith and settled in Ashland, Massachussets. They had no children.

Father:

Henry Warren

Mother:

Adelaide Louise Ellis

Spouse:

Edith B. Smith