telegraph relay
Datecirca 1890
Inventory Number1997-1-0573
ClassificationTelegraph Relay
Subject
Maker
Western Electric Company
1869 - 1995
User
Department of Physics, Harvard University
founded 1884
Cultural Region
Place of Origin
Dimensions9.5 × 19 × 10 cm (3 3/4 × 7 1/2 × 3 15/16 in.)
Material
DescriptionTelegraph relay mounted on a black rectangular base. Two black cylinders (an electromagnet) lie in the middle of the base. They are attached in the back by a metal plate, which is in turn attached to a screw with an adjustment dial on the end. Between the cylinders, near the front, is a piece of metal on which stands a solid metal rod, shaped in an arc. There is a double adjustment knob on either end of the rod. A movable black piece of metal, with a hook in front, extends from the front of the magnets upward to the middle of the arc of the rod. A long metal rectangle, with no bottom and an oblong slit on top, extends from an adjustment dial at the front of the base to just in front of the front metal plate.
Signedon instrument: WESTERN ELECTRIC / MADE IN U.S.A.
Inscribedon base: 2LB / 100 OHMS
on magnet: 50 / 58
FunctionThis telegraphic instrument was used as control relay. It could be used to control the current flow between other telegraphic instruments and switchboards. When a current flowed through the magnet, it would attract the metal plate in front. When the current ceased to flow, the plate would return to its resting position. The effect was that of opening and closing a switch.
ProvenanceFrom the Department of Physics, Lyman Laboratory, Harvard University.
Burnell Telephone and Electric Company
Date: circa 1905
Object number: 1997-1-0571
U.S. Electrical Supplies
Date: 1910-1920
Object number: 1997-1-0578
