Electrical transmission of energy

Abstract

Introduction: In later years the invention of the dynamo and motor led to their experimental use for this purpose. They proved to be satisfactory, with one serious exception, their efficiency was too low, there was too great a waste of power. Of the original power from the engine, only one fourth, or even less was obtained from the motor, and in such a case it was too expensive unless for very small amounts of power, or for short periods of use. But later dynamos were constructed having an efficiency of 90% to 95% and motors practically the same and by using large conductors, from 75% to 90% of the power generated by the engine could be obtained from the motor. With an ultimate efficiency of 90%, or even 75%, power in small amounts, or for limited periods, becomes more economical than the use of an engine for such power for the following reasons: First, the cost of labor and fuel represented by the energy lost in firing up and cooling of the boiler is far less in one large boiler kept in use all day than for many small boilers fired up once or twice a day and for only a few hours. Second, a large engine is much more efficient than a small one; we get a greater return, proportionately, in relation to the cost of fuel and care. Third, the motor does not require an experienced attendant, as does the engine, the engineer at the central station may answer for fifty or a hundred motors.