The “Heavisidion” a computing kinematic device for long transmission lines

Subject of the Paper. — A kinematic computing device is described which can be set to represent vectorially the voltage and the current at any point of a long transmission line with uniformly distributed properties and with a given load. The device has been named after Oliver Heaviside who was among the first to establish and to solve the fundamental differential equations of such a line. The parts of the device are made to assume at will different positions corresponding to different points on the line. The constants of a line to be represented by the device are adjustable at will, and a complete set of performance curves of a given transmission line can be obtained. Conversely, by a few simple trials, the best constants of a line and the necessary kv-a. of a synchronous condenser may be found, to give the required performance characteristics. The current, the voltage, and the power factor (or the phase angle) can be read off directly on the device for any desired point of the line, including the generator and the load end. Results of computations are shown for two transmission lines, 1000 and 300 miles long, values having been obtained in the usual tedious way by means of hyperbolic functions of a complex variable, and also read off directly on the Heavisidion. The agreement is as good as could be desired, showing that the device is reliable and that a considerable saving in time is possible with it. The device consists mainly of steel and celluloid bars, proportional dividers, parallel double tongs, and other simple kinematic linkages. Two sharp-edged wheels are used, similar to those used in planimeters. The parts are so combined as to satisfy the familiar exponential vectorial expressions for the sinusoidal voltage and the current, the independent variable being the distance from one of the ends of the line.