Marcell Depréz has laid down in a work of his,[4] the laws which make it possible to hold the points of consumption of electric energy independent of one another, and, excepting some inexactnesses which crept into his representation, these laws have been almost all carried out in practice since that time.
The system of direct distribution to glow lamps had the one well-known serious drawback, viz. that it only allowed of limited employment, because the cost of the leads, with equal loss of energy, increased with the square of the distance from the source of current.
It was therefore obligatory, in order to carry the current economically to greater distances, to seek new means and ways, without rendering inefficient the only practical system of connecting incandescent lamps in parallel. The experience which had already been gained in the economical carrying of high tension currents with arc lamps in series, pointed out that high tension currents should be used, and that in the secondary circuits of transformers fed by such a current, consuming devices could be connected as might be desired.
H. Enuma, 1881.
Haitzema Enuma, in the year 1881, was the first to go in this direction, and took out a patent for the feeding of glow lamps by means of transformers.
He followed the principle of making each secondary circuit and each point of consumption independent. The means to this purpose which he thought to employ were not practical, and did not at all differ in substance from those of his predecessors. His system is remarkable for his method of connecting the induction coils in the main lead, i.e. in series, using the secondary currents from these coils to excite other coils from which tertiary currents were received, and these again were further used to excite quaternary currents, and so on. This procedure stands on a level with that of the famed dynamo-electric chain of Siemens and Halske, of which it has been asked, “To what purpose?”
The peculiarities of the system of Haitzema Enuma become evident from the following extract from his patent:—
“Solche (nämlich die bekaunten) Induktionsrollen werden in den Hauptstromkreis überall eingeschaltet, wo der Strom abgezweigt (!) werden soll; und durch diese Einrichtung erhält zuletzt jede elektrische Lampe, oder jeder durch Elektrizität in Betrieb gesetzte Apparat seinen eigenen Strom.”
Haitzema Enuma had intended, so far as this shows, to connect the primary, secondary, tertiary, &c., coils in series, and the main lead being a closed circuit, the ends were taken to earth. The ends of the circuits of the secondary, tertiary, and further induced currents, were also connected together, or to earth.
Gaulard and Gibbs, 1883.