Tesla Did Not Invent Alternating Current Power
The Distribution of Electricity by Induction.
There has been much said in recent
times about the distribution of electricity by means of induction coils,
and the use of this process has given rise to several systems that differ
but little from one another in principle.
The following are a few details in regard to a system due to a Dutch engineer:
"In the month of December, 1881 a
patent relating to the distribution of electricity was taken out in Germany
and other countries by Mr. B. Haitzema Enuma, whose system is based upon
a series of successive inductions. The primary current developed by a
dynamo-electric machine gives rise to secondary, tertiary, etc., currents....
The induction
is effected by the aid of bobbins whose interior consists of a bundle
of soft iron. The wire of the inducting current is wound directly around
this core. The wire of the induced current is superposed upon the first
and presents a large number of spirals. It is useless to say that these
wires must be perfectly insulated from each other, as well as from the
soft iron core....
Each electric apparatus, whether it be a lamp or other mechanism, is furnished
with a special current. If the number of these apparatus be increased,
it is only necessary to increase the number of bobbins in the same ratio...
As regards to lighting, it is preferable to employ alternating current dynamo machines; yet there is nothing to prevent the use of continuous current ones, provided that there is an arrangement that permits of constantly opening and closing this same circuit..."
La Lumiere Electrique
The bobbin referred to is what we call today a step-down transformer just like those on utility poles in the alley behind your house. They operate on the principle of induction.
So about the time Enuma was patenting his system, Edison was constructing the direct current Pearl St station in New York City. In the beginning DC was preferred possibly because it was easier to understand. It was usually preferred because dynamos could fail and be off line for hours or days at a time. Batteries could be put across dc mains to provide emergency power. And generation of AC at the time was thought to be less efficient than DC, and that may have been true because soft iron is not as magnetically efficient as modern silicon steel.
It could very well be that when Tesla arrived in the States a few years later, he concentrated on AC power because he already knew it worked, and dreamed of the fame and fortune it might give him. AC power was yet another idea that Tesla lifted from someone else and attempted to improve upon.
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