telegraph relay

Date1890-1930

Inventory Number1997-1-0574

ClassificationTelegraph Relay

Subject

Maker American

Cultural Region

Dimensions12.3 × 20.9 × 8.6 cm (4 13/16 × 8 1/4 × 3 3/8 in.)

Material

DescriptionTelegraph relay mounted on a wooden rectangular base with rounded corners, the base sitting on a black piece of metal. In the middle of the base lie two black cylinders (an electromagnet), connected in the back by a metal plate. A thick coil extends from the plate through a metal knob. A binding post stands to either side of the knob.

A piece of metal sits between the cylinders in front, with an arc-shaped rod sitting on top. Each end of the rod has a screw with two adjustment dials going through it. In front of the magnet is a movable metal plate, wide at the bottom with a narrow arm extending up into the middle of the arc of the rod. An arm, with an adjustment dial on the end, extends from the left of the front plate through a metal knob in the front-left corner of the base. Two binding posts stand in the right-front of the base.

Signedunder magnets: WESCO

Curatorial RemarksWESCO is written on a tag accompanying the instrument. This could be either Wesco Supply Co. based in St. Louis or the Wesco Co. founded by Westinghouse to distribute their products. The latter was founded in 1922.

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.