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Earth-return telegraph is the system whereby the return path for the electric current of a telegraph circuit is provided by connection to the earth through an earth electrode. Using earth return saves a great deal of money on installation costs since it halves the amount of wire that is required, with a corresponding saving on the labour ...
The choice of earthing system can affect the safety and electromagnetic compatibility of the installation. Regulations for earthing systems vary among countries, though most follow the recommendations of the International Electrotechnical Commission (IEC). Regulations may identify special cases for earthing in mines, in patient care areas, or ...
Long-distance electromagnetic telegraph systems from 1820 onwards [a] used two or more wires to carry the signal and return currents. It was discovered by German scientist C.A. von Steinheil in 1836–1837, that the ground could be used as the return path to complete the circuit, making the return wire unnecessary. [2]
The telegrapher's equations (or just telegraph equations) are a set of two coupled, linear equations that predict the voltage and current distributions on a linear electrical transmission line. The equations are important because they allow transmission lines to be analyzed using circuit theory . [ 1 ]
Installation of the lines and poles from Washington to Baltimore began on April 1, 1844, using chestnut poles 23 feet (7 m) high spaced 300 feet (90 m) apart, for a total of about 700 poles. [6] Two 16- gauge copper wires were installed; they were insulated with cotton thread, shellac, and a mixture of "beeswax, resin, linseed oil, and asphalt."
Examples of unbalanced lines are coaxial cable or the historic earth return system invented for the telegraph, but rarely used today. Unbalanced lines are to be contrasted with balanced lines , such as twin-lead or twisted pair which use two identical conductors to maintain impedance balance throughout the line.
Provide a source of ground fault current during line-to-ground faults. Permit the connection of phase-to-neutral loads when desired. [2] Earthing transformer with a zig-zag. Grounding transformers most commonly incorporate a single winding transformer with a zigzag winding configuration, but may also be created with a (rare case) delta-wye ...
Earth return or ground return is an electric circuit using the earth for one conductor. It may refer to: Earth-return telegraph; Single-wire earth return, an electric power distribution system; Simplex signaling, an earth return signalling system used in telephony