Omaha daily bee., 1889-11-03
S. P. MORSE eco
TWIN-BR0THER OF STEAM.
How the Electric Current Moves
the City Pullmans.
TWO NEW MOTOR SYSTEMS.
A Description of the Magnets, Arm =
atures Motors of Each, With
the Means sofsupDlying Big
Power.
The Subtle Current.


As couple of men stood on Sixteen tn
street yesterday watching the beautiful
motor train as it went whzzing by, one was
asked by his companion If the cars were not
propelled by the friction of the trolley wheel
on the overhead wire
"Oh, no." wisely replied the other, ''the
overhead wire is in constant motion like the
cable, and 1t draws the cars along" ana he
assumed the important air of a man who has
impaired some valuable information.
Many citizens enjoy the comfort, speed
and beauty Of the electric cars, but know lit
tie about the workings of the subtle fluid by
which they are propelled. They know that
somehow there is current of electricity
which causes the locomotion, but at that
point their knowledge ceases.
There are two power houses in Omaha,
each representing a different system, the
Sprague and the Tho mpson-Houston. The
princi pies of both are essentially the same.
The power house on Nineteenth and Nicho.
las, where is generated the propelling force
for the Hanscom Park and North Twenty
fourth street line represents the Sprague
system.
A study of one OF the dynamos there gives
an insight into the workings OF the whole
system and Is much moro simple than many
people imagine. The dynamo is really an
immense horse shoe magnet, with the prongs
extending upwards. These prongs are
wrapped with wire until they resemble colos
sal spools. The curved part of the magnet
is termed the pole piece and in it is sus-
pended the armature. The latter Is made up
of series of iron disks around an axle
and the outside of these are wrapped
with four or five thicknesses of fine
wire extending lengthwise instead of aro und
the disks. Each disk and all the wires are
insulated. On the axle of this armature are
number OF narrow copper plates, insulated
from each other with still narrower strips
of mica This covering is called COM
mutator. The immense horseshoe magnets
have had current of electricity passed
through them before they We're sent from
the factories, and there is a residuum of
electricity left IN them, although it is only
apparent by the use OF a delicate maget
The machinery causes the armature to re-
volve 600 times per minute, and these revoiu-
tions, with the residuum of electricity in the
pole piece as starter, cause constant gen
Grafton of the electrical fluid. The cleo
tricity flows into o cOmmutator and is caught
by strips of carbon called 'brushes'' press
ing against the commutator in its revolu-
tions.
Two wires are attached to these brushes
One is known as the positive and the other
the negative WIRE. The positive extends to
the overhead wire and tine negative con-
meets with the tracks. AS the tracks are
good conductors OF electricity, they answer
the purpose Of the negative wire. The only
thing necessary TO complete the circuit be-
tween tho positive and Negative wires is
some conductor OF electricity between the
overhead wires and the tracks.
This Is effected by the trolley and a wire
extending to the wheels.
The motors in the car are under the floor.
| They are really small dynamos, being exactly
like the dynamos in the powerhouse only they
are much smaller. They have armatures,
commutators and brushes like the dynamo.
There are two Of them and they are directly
| connected with each other by copper wire
The circuit is made complete or is broken by
| OF the motor car. When the armature of the
dynamo at the power house Is put In motion
and the motorman on the car tnrns the
switch bar completing the current, the arma