telegraph relay
Date: circa 1903
Inventory Number: 1997-1-0568
Classification: Telegraph Relay
Subject:
Attributed to: Western Electric Company (1881 - 1995)
User: Department of Physics, Harvard University (founded 1884)
Cultural Region:
Dimensions:
9.5 × 18.6 × 9.9 cm (3 3/4 × 7 5/16 × 3 7/8 in.)
Description:
Telegraph relay mounted on a black, rectangular base. Two black, horizontal coils (an electromagnet) lie in the centre of the base. A black metal plate connects the cylinders in the back. A bronze metal rod with an adjustment dial on the end extends from the back plate into a metal brace. Between the coils, near the front, is a metal circle on which stands a solid metal rod, shaped in an arc. There is a double adjustment dial on either end of the rod.
A movable black piece of metal, with a hook in front, extends from the front of the magnet 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. Beneath the rectangle there is a movable, triangular piece of metal with a black knob on the end, free to pivot around a metal screw.
A movable black piece of metal, with a hook in front, extends from the front of the magnet 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. Beneath the rectangle there is a movable, triangular piece of metal with a black knob on the end, free to pivot around a metal screw.
Signedon back plate: WESTERN ELECTRIC
Inscribedon base: No 22A / 100 OHMS
on back plate: JULY 21 1903 MADE IN USA
on back plate: JULY 21 1903 MADE IN USA
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.
Curatorial RemarksPatented July 21, 1903
ProvenanceFrom the Department of Physics, Lyman Laboratory, Harvard University.