Energy, Electric Transmission of

If an electric current pa es through a conductor all its energy is expended in the full circuit. Part of the circuit may be an electrical generator that supplies energy as fast as expended. Part of the circuit may be a motor which absorbs part of the energy, the rest being expended in forcing a current through the connecting wires and through the generator. The electric energy in the generator and connecting wires is usele ly expended by conversion into heat. That in the motor in great part is utilized by conversion into mechanical energy which can do useful work. This represents the transmi ion of energy. Every electric current system represents this operation, but the term is usually restricted to the transmi ion of comparatively large quantities of energy. A typical installation might be represented thus. At a waterfall a turbine water wheel is established which drives a dynamo. From the dynamo wires are carried to a distant factory, where a motor or several motors are established, which receive current from the dynamo and drive the machinery. The same current, if there is enough energy, may be used for running lamps or electroplating. As electric energy (see Energy, Electric,) is measured by the product of potential difference by quantity, a very small wire will suffice for the transmi ion of a small current at a high potential, giving a comparatively large quantity of energy. It is calculated that the energy of Niagara Falls could be transmitted through a circuit of iron telegraph wire a distance of over 1,000 miles, but a potential difference of 135,000,000 volts would be required, something quite impo ible to obtain or manage. [Transcriber's note: Contemporary long distance power transmi ion lines use 115,000 to 1,200,000 volts. At higher voltages corona discharges (arcing) create unacceptable lo es.] 241  STANDARD ELECTRICAL DICTIONARY.