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A black circular metal instrument with a large analog display. Its gradation goes up to 9 and is measured in “thousands of vibrations per second”. The instrument has two black round knobs on the bottom and three metal pillars with screws on top. A piece of tape on the bottom details the basic movement and present wiring: “Basic Movement, 13 Ma @ 2.52 Ohms; Present Wiring, 0 – .9 Volt, 69.3 Ohms, 770 P.A.”

Accession Number: 2011.psy.28

Alternative Name:

Primary Materials: metal, glass


There are manufacturing details inside the display: “Made by Westinghouse Electric and Manufacturing Co.; For The Electric Tachometer Corp., Philadelphia, PA; Style No. N-505876, Type SX; Sr. No. 642965”.

Dimensions (cm): Height = 10, Width = 20, Length = 20


Measuring the rotational speed of a shaft or disk.


Good. There are elements of debris inside the display. There are glue marks on the side indicating the instrument had something tapped to it which was then removed.

Associated Instruments:


Westinghouse Electric Manufacturing Co., Philadelphia, PA, U.S.A.

Date of Manufacture:


Dept. of Psychology, University of Toronto

Additional Information and References:

Historical Notes:

Westinghouse Electric was an American manufacturing company. It was founded in 1886 as Westinghouse Electric Company and later renamed Westinghouse Electric Corporation by George Westinghouse. The company purchased CBS in 1995 and became CBS Corporation in 1997. George Westinghouse had previously founded the Westinghouse Air Brake Company.

The company pioneered long-distance power transmission and high-voltage transmission. Westinghouse Electric received the rights for the first patent for alternating-current transmission from Nikola Tesla and unveiled the technology for lighting in Great Barrington, Massachusetts.
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