Cooper Hewitt Electric Co.
220 West 29^th St, New York City, New York

Also:
Hewittic Electric Co. Ltd, 80 York Rd, Kings Cross London N1
Hewittic Electric Co Ltd, Walton on Surrey, England
Hackbridge and Hewittic Electric Co, Walton on Surrey, England

Manufacturers of mercury vapor lamps, mercury arc rectifier tubes and associated equipment.

Peter Cooper-Hewitt was born in New York City, of a very wealthy family, on March 5^th, 1861. He attended Stevens Institute of Technonlogy and Columbia University School of Mines and received an Honorary Doctorate in Science in 1903.

In 1901 he invented a mercury vapor lamp, which he patented. These lamps had to be tilted so that there was a continuous stream of mercury between two electrodes at opposite ends of a two foot length of glass tube, which would make the lamp "strike". The lengths of these tubes depended on the output of the lamp. One end of the tube was a resevoir for the mercury. Lamps were usually mounted on a ceiling fixture and there was a chain attached to the other end of the tube so that the lamp could be tilted, closing the circuit with the mercury stream. The lamps needed starting and he developed an inductive ballast for this purpose. The efficiency of the lamps was much greater than that of the carbon filament lamps of the time, with the disadvantage of a blueish green hue of the emitted light. In spite of this drawback, the lamps enjoyed some commercial success.

From 1907, Hewitt became involved with other interests such as hydroplanes and powered flight. He served in the Board of the Inventors Guild. He was appointed to the Naval Advisory Board in 1915 and received three patents on a helicopter in 1920.

Hewitt died in August 1921.

In 1902, with financial backing from Geroge Westinghouse (see Westinghouse Electric and Manufacturing Co.), the Cooper Hewitt Electric Co. was formed.

They developed a large mercury vapor rectifier tube and associated equipment to run it, which would revolutionise industries where high voltage DC current was in use.

These rectifiers were used for tramways, elevator motors, electroplating and the like. They were able to be used by some radio stations in relation to power supplies needed for transmitters. Some cities, such as Sydney, used the rectifiers for DC power station supplies for vast areas. It is known that the Clarence Street Electricity Sub-station in the heart of Sydney was still using a single rectifier unit to drive a DC operated elevator a few blocks away. This last use was discontinued around 1989. The sub-station originally had sixteen rectifiers mounted in frames and each nearly a meter in diameter, that were driven in pairs by eight rectifiers half the size. There was enough mercury in each large tube to fill a soup bowl.

Many of these huge tubes can be found in various technical and transport museums today.

The company also formed the Westinghouse Hewitt Company in the UK, Westinghouse Cooper Hewitt GmbH in Germany, Westinghouse Cooper Hewitt in France (which became Hewittic later on), as well as others.

In 1919 General Electric assumed control of the American company. [1][2]

Semiconductor devices of high power replaced the Hewitt rectifiers generally in the 1970's and 1980's.

[1] The Commercial & Financial Chronicle, Vol 108, June 14, 1919
[2] Hearings to Amend Sect. 7 & 11 of the Clayon Act, US Congress, May 23 1945