The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1898-01-27
ELECTRICAL SCIENCE.
why Electric Motors Do Not SuppIant
Steam Locomotives.

Boston Transcript.
1T is remarkable what number of per-
sons of intelligence there are who have the
impression that by the use of electricity
five or six-horse-power will do the work OF
fifty or sixty-horse-power produced by
steam" said an electrician. only few
days ago sucl. a person said to me in good
faith that b. Believed that electric motors
would soon take the place or steam loco
motives for general railroad use, because
little electric motor of five or six-horse-
power would be able to do the work OF the
heaviest engine. The real economy or the
electric motor does not lie in its being able
to do any more work for each horsepower
than could be done by the steam engine,
but in the fact that the power Tor many
motors can be generated at or central sta
ton under conditions of much greater econ
omy than can be secured in the locomotive
or in small separate plants. and also in the
greater efficiency for certain purposes OF
rotary motor over the reclprocatlng actioh
of the ordinary steam engine speaking gen
orally, the power all comes from coa1 oTlsl-
nally and the steam engine is USED 10 drive
the electric generators or dynamos, as they
are called. If there were hundred ma
chimes to be driven and each Of these would
take five-horse-powe they would each re-
quire an electric motor of the same power
as if the motor were a steam engine, ana
the whole would require a central station
engine which could furnish to them 1lXe-
acknowledgements in the aggregate Inc
loss of power In good practlce amounts 70
from 6 TO 10 per cent, so that the central
station must actually produce, in sucn
case, fifty-horse-power perhaps more tnan
the separate steam engines to perform the
same work would be required to do. You
wonder then, where the economy of using
electricity lies. Let us consider this as APP
piled to the running of locomotives, for in
stance. An express locomotive, running I'M
der favorable conditions, will use
for each horsepower produced. Some
runs have been made upon a
consumption of three and one~halt pounds
an hour for each horsepower. An engine
drawing local train will burn five pounds
of coal every hour Tor each horsepower
while the usual consumption of freight To-
connective is from six to ten pounds. Even
this does not take in the coal wasted while
the engine is getting up steam or that
burned when the fires are banked or thrown
away when the fires are drawn Compare
this with the results attained in good sta
tionary plants. Some of these will produce
power at an expense of 1.5 pounds of coal
Tor each horsepower an hour, while IL is
a poor plant which requires more than TWO
pounds. In the new steamship Kaiser VIII
helm der Crosse the engines produce 10000
horsepower upon an average consumption
of one and one-half pounds OF coal Tor each
horse power an hour for run across the
Atlantic. Coal can be delivered and handled
cheaper at large central stations, ana the
other expenses are also less. AS a rule,
the cost of fuel on electric roads is about D
per cent. of the operating expenses, While
on steam roads it is about 10 per cent. The
real reason why the electric locomotive does
not at once take the place OF the steam
motor is the difficulty and cost of distribute
ing the electric current for long distances
without a great loss OF current through the
electrical resistance of the wires. To over
come this the roads operated by electricity
are divided into short sections and separate
copper feeder wires are run from the power
house to each section. This would not en-
tail so much expense il it were not for the
fact that each feeder wire as 1t Is increased
in length must also be increased in size, or
there would be a great loss of power, and
the cost of the copper soon gets TO be too
great to warrant the increase in size. When
the scheme for building the Broadway UNI
foreground capld transit railroad was being
Investigated by a Supreme Court commits
Sin in ayr oaT re
the enormous amount of power which would
be required for the proposed train service
would take $I,00O,U00 worth or copper wire
alone if the power all came from one sta
tion''f
These difficulties were set forth recently
by Claude Marshall in a paper read before
the Chicago Electrical Association and Mr..
Marshall also points out a way in which
they may be overcome. He says. in part:
LAS far as an engineer can see into the
future, it is improbable that electricity Will
supplant steam for general railroading pur-
poses, but there are some departments of
the work where the adoption Of electricity
will be a great advancement. In thickly
settled communities, as parts OF the New
England North Atlantic and Central States,
the railroads will be forced to make changes
in their service to successfully compete with
the parallel trolley lines With the present
equipment it seems that 500 or 600 volts at
most is the limitation of the direct current
motor, and long lines can only be operated
by placing power stations at frequent inter
walls. say ten or twelve miles apart. The
transmission at this voltage involves enor-
nous losses or great expense for copper.
On one road recently tested the voltage
varied from 525 volts near the station to 240
volts at the end of a line seven miles dis
tant. 1t is obvious that for transmission
alternating currents must be employed.
How necessary high voltages are may be
seen from little calculation on the cost
of copper for line wire. Mr. Stillwell gives
the cost of copper required to deliver one
horse power at motor shaft ten miles from
the generator, allowing d 20-per-cent. drop
and copper Is cents per pound at 500 volts,
$3.50 10 and 10000 volts. 81. 30. Thus 1t is
seen that it costs four hundred times as
much to furnish copper at 500 volts as it
does at 10000 A voltage of 10000 is well
is generally believed that alternating cur
rent motors are out of consideration for
experiments have not been successful on
account of the low starting torque and lack
of regulation; but the improvements which
have of late been made go far in perfecting
this machine.