The herald., 1897-06-06

sides being impra cticable to use cop
per wire large enough to carry the cur
rent of large power plant any distance.
Here lay the principal difficulty in the
way of long distance transmission and
it is only recently that inventive genius
has successfully got around it. Nicola
Tesla has given the question a great
deal of attention and several years ago
discovered the principle that has sue
cessfully dealt with the problem. Mr..
Tesla, it should be said, is by no means
entitled to all the credit, for while he
discovered the principle, others have
most successfully applied it.
The key lies in the ability to increase
the potential of the current of electricity
so that great amount of power may pe
transmitted over an ordinary wire. Let
me use an humble ILLUSTRATION somo-
thing after the fashion of the Georgia
darkeys idea of the telegraph, promis-
ing to add to it something more SUBJ
stantial.
AN ILLUSTRATION.
Have you ever read "Alice in Wonder
land?" Don't laugh. you old fellow with
the gray hair, because ideas can be got
from book adapted to the mind of the
smallest of your children. You will re-
member that Alice, by eating and drink
ing certain mysterious things, could
make herself a 20-foot giantess or an
inch-tall fairy, according to the need
for her adventures in Wonderland.
Well, that is exactly the same idea that
is used in the transmission of electric
power to long distances. The form OF
~l,1 I,o%
voltage of many thousands can be car
ried over ordinary wires. AS it is thus
carried, it would be comparatively val
ueless for commercial purposes. So
genius now comes into play again and
by the use of a similar agency to that
which changed the original form of the
current, the electricity becomes as it
was gathered miles away, ready by the
means of wonderful devices to be par
celled out in job lots and quantities 10
suit.
This remarkable fact is made possible
by the converter, or the transformer, as
it is more commonly called. l shall as
sumo that readers Of this paper are fa-
m;liar with the process Of collecting the
subtitle fluid we call electricity because
it has for years been familiar one, and
deal more particularly with the prob
lem of transmission.
We will assume that the electricity is
ready to transmit, say from the Sierra
Madre mountains to Los Angeles, hav-
ing been secured by means of water
power applied to electric generators.
The current is a large one and cannot
be sent by ordinary methods over the
wires commonly put in use.
THE TRANSFORMER
Right here is where the wonderful
transformer comes in and makes pos
sible the longdistance transmission of
electricity. To transform, or convert, as
the words are used in electrical science,
means to change the electro-motive
force, and consequently simultaneously
TO change the current strength of the
circuit by any means. electro motive
force is the force that moves or tends to
move electricity or start it in, motion
The unit of electro-motive force is the
volt)
The transformers are of two kinds
The step-up transformer is one in which
a large current of electricity of compar
atively small difference of potential is
converted into a small current of conn
paratively great difference of potential
The step-down transformer is one ir
which small current of comparatively