high-speed polarized telegraph relay
Date: 1900-1920
Inventory Number: 1997-1-0590
Classification: Telegraph Relay
Subject:
Maker: Western Electric Company (1881 - 1995)
Supplier: American Telephone and Telegraph Company (1885 - 2005)
User: Department of Physics, Harvard University (founded 1884)
Cultural Region:
Place of Origin:
Dimensions:
7.5 x 21.3 x 12.4 cm (2 15/16 x 8 3/8 x 4 7/8 in.)
Description:
Telegraph relay mounted on a rectangular wooden base, the latter sitting on an additional black metal base. Two metal cylinders face one another in the middle of the base, the cylinders positioned at the ends of a horseshoe-shaped, thick piece of black metal. A thin piece of black metal runs between the cylinders and continues into a piece of brass. The brass is attached to a thin metal bar that runs between two brass posts, each with a double adjustment knob on the outer side.
A brass bar extends horizontally from one side of the horseshoe-shape to the other, with two brass springs hanging down from it. There is a brass turning dial at the back.
A brass bar extends horizontally from one side of the horseshoe-shape to the other, with two brass springs hanging down from it. There is a brass turning dial at the back.
Signedon plaque on base: WESTERN / ELECTRIC / MADE IN USA
on base: AT & T CO / No. 7 / 31 A 400 OHMS
on base: AT & T CO / No. 7 / 31 A 400 OHMS
FunctionThis telegraphic instrument was used as a control relay. It could be used to control the current flow between other telegraphic instruments and switchboards.
ProvenanceFrom the Department of Physics, Jefferson laboratory, Harvard University, 3/3/61.