telegraph relay with light shutter
Datecirca 1905
Inventory Number1997-1-0571
ClassificationTelegraph Relay
Subject
Attributed to
Burnell Telephone and Electric Company
Cultural Region
Place of Origin
Dimensions10.5 × 16.9 × 9 cm (4 1/8 × 6 5/8 × 3 9/16 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 coils (an electromagnet), connected in the back by a metal plate. A thick coil extends from the plate through a metal knob, an adjustment dial on the far end of the knob. A binding post stands to either side of the knob.
A piece of metal sits between the coils in front, with an arc-shaped rod sitting on top. A black light shutter sits on top of the rod. 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. A black piece of metal runs up from the plate into the light shutter. A thin metal wire runs from a hook on the metal plate to a tall knob in the front of the base. Two binding posts stand in the right-front of the base.
A piece of metal sits between the coils in front, with an arc-shaped rod sitting on top. A black light shutter sits on top of the rod. 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. A black piece of metal runs up from the plate into the light shutter. A thin metal wire runs from a hook on the metal plate to a tall knob in the front of the base. Two binding posts stand in the right-front of the base.
Signedunsigned
Inscribedon base: 20 OHMS
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, Jefferson Laboratory, Harvard University.
U.S. Electrical Supplies
Date: 1910-1920
Object number: 1997-1-0578
