Evening star. [volume] (Washington, D.C.) 1854-1972, 1890-07-05
ELECTRICITY AS A MOTOR
What IL 10 That Makes the Wheels &C
Round.


The conclusion has about been reached that
electricity is something whose real nature we
do not understand We know what il will do
as motor power and We have practical exam
pie on all sides of lite real value, but what il
Is as thing no one really understands. Or il
any one does he has not as yet succeeded in ex-
planning il so that the average man knows whas
he is talking about And when 1t comes TO har-
Messing up this invisible, ineomprebensitle
fluid and putting it to work the popular mind
is far out at sea. Why will a current Of such
a peculiar nature run machine or move
street car? This was the question q STAR re-
porter recently prepounded to an expert at
tached to an electric street railway company.
III seems odd TO me" was his answer. 'bow
Few people understand the simple principles
that underlie the system. Ii is very easy when
you know how it Is all done. But come. wall
explain 1t to you briefly if you wish. but 10 not
De surprised If use some technical terms, for
ike TO be precise. But will endeayor 10 make
1t very PLAIN
GENERAL FAcra
I'm the first place there are some general
underlying facts that you, of course. are more
or less familiar with. For instance, II con-
meet one end of q rod of zinc and the other
with rod OF carbon and put the two rods into
tumbIer filled with a solution of bichromate
OF potash and attach them TO an iron nail
around which a thick copper wire is ccIled. the
enos OF the nali Will act as magnet. Any coil
OF wire surrounding iron acts as q M gnet when
a current or electricity flows through the coil
inns is starting point. But LET us TAKE of tho
battery and bring the ends of the wire very
near 10 each other. not quite so close as 10
touch one another, however. and place the coil
on one pole OF powerful magnet and sud-
denly remove the coil. and you will observe a
spark passing between the ends OF the wires.
The spark is the evidence that a coil near a
magnet can produce a current OF electricity
Without battery. Thus a dynamo is con-
structed by moving coil of wire near a magnet
that is traversed by a current Of electricity
This coll itself becomes a magnet when the
current flows through il. and this is what fur
nishes the motive power Of an electric car.
For practical purposes VIC follow this princi-
pie and put a number of coils on an axle and
turn the coils by means of some motive power
near the poles of powerful magnet The coils
passing the poles of the magnet with great
speed increases the current of electricity in
proportion to the revolution Of the coils These
coils OF wire, so revolving between the poles of
magnet. together with the magnet constitute
what is called a dynamo.
WHAT REvoLvEs THE COILS.
do You understand all this? Well, now you
notice that thin overhead wire-not strag
enough, Of course, to pull the car-but it isn't
the wire, nor the dynamo, nor the motive
power that revolves the wire coils; it's all Of
them taken together. The engine gives We
loclty to the revolutions OF the coils around the
magnets and the magnets send the innumer-
able sparks Of electricity over the wires, which
passes down the traveller on the top OF each
car to a little dynamo similar to the central or
chief dynamo. This little dynamo has an
armature consisting of coils on a shaft ira
versed by an electrical current, and this being
attracted III succession TO the poles Of the sta
flnnorv n.rsln la1 h., @xHl
through which the current also flows flies
around and turns, by means Of cog wheels the
wheels of the electric cars. You see now why
the car moves, L presume. The man at the
end of the car, by means Of a lever. can turn
the current of electricity into the dynamo be-
meath the car or divert 1t to the rails by an
other path.
'Oh, yes" further explained the expert.
''instead Of the overhead wire q wire can and
is often laid through an open trough along the
side OF the rails. But this wire must be carefully
insulated from the rails There is slso a contriv-
ance that takes the place of the traveller in the
overhead wire. which grips this wire as the car
passes along.
IN THE CONDUIT SYSTEM
the current passes along the wire, which is
gripped, into the motor or dynamo on the car
and then out through the wheels to the rails
and then back to the central dynamo This
system is not SO satisfactory as the overhead
system, for If the rail and wire are connected
anywhere the wire burns and the current is
stopped and this stops all the cars. These in
nocent and quiet looking wires are treacherous,
for though they look SO harmless they are
really very dangerous, for q shock from them
means sudden death.
by the way, let me advise you IL you ever
have occasion to pick up piece of wire on the
street do not do it unless YOU have a pair of
insulated pincers. But there goes MY car, and
l am in hurry. So goodbye to you. only
once more, do not fool with what you NAV
think is dead wire. 1t may be you instead OF
the wire ~