New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1903-10-12
DETAILS OF ELECTRIC FRICTION.

Almost simultaneously with the recent re-
sumption of experiments on the Marienfefde-
Zossen line, In Germany, tests of kindred
character have been initiated on suburban
road In the city of Berlin. Between the Two
there is one noteworthy point OF difference In
the former case three phase alternating cur
rents are used. and in the latter instance the
one phase system Is being tried. Fifteen ana
twenty years ago. when the ordinary alternat
ing current was introduced successfully for
lighting purposes. peculiar difficulties were en-
countered in attempts to apply 1t to power ser
vice There was no trouble about the dynamo
or the line, but II was hard to design motor
so that IL would act In all respects as satisfac
torily as the direct current motor. At length
one was designed that called for two or three
separate alternating currents. slightly diff
ferent form Of generator was required to sup
ply the current but the motor gave materially
better results than that which was driven by
a single current However. advances In the de-
sign of the one phase system have been effected
in the last few years. Whether II Is now In all
respects as efficient and convenient as the poly
phase system Is highly interesting question
and the trials which hav been instituted in the
German capital possess peculiar interest on that
account.
Another problem on which light is TO
be obtained for the first time relates to the
feasibility Of doing without transformers. 1t
has been accepted as automatic for the last few
years that for long distance electric service on
| trunk lines-say. between Berlin and Hamburg
the alternating current must be used. and that
for economy In transmission 1t must be gener-
ated at a high voltage. 1t has been deemed
necessary hitherto to reduce the latter more or
less before admitting the current to the motor.
On a railway in the Lake Como region Of Italy.
equipped by CAM & Co., Of Budapest, the line
voltage is about 10000. and small sub-stations
are placed here and there to ira usform 1t down
TO 1900. The voltage employed on the Marien-
felde-Zossen line two years ago was substan-
TALLY the same, but the transformers were
placed upon the car itself, the reduction In that
instance being to 1900 volts Some of the tests
now being made are based on that plan. but n
new car has been built from which transform
ers have been omitted entirely. 1t is not clear
from the cable dispatches whether this has yet
been tried, but it will be heard from sooner or
later The car employed for the one phase ex-
periments In Berlin also dispenses with trans
formers. although the voltage on the line is
only 6.000. Between the two sets of investiga-
tons. therefore, the world ought soon to learn
something about the wisdom of thus simplify
ing electric railway equipment
The feature of the German experiments which
appeals most strongly to the general public. no
doubt, is the attempt to discover where the
limit of speed with safety lies. Less curiosity
is felt this point by experts In electric trac-
ton. Incidentally, Of course, they want to
know whether velocities never before attained
will interfere with the operation Of taking off
the current from the conductor. II is also TO be
ascertained at what point atmospheric resist
ance becomes prohibitive to progress So far as
the motive machinery proper is concerned
though. electricians are confident that II will
prove adequate to any speed which is ever de-
manded of It whether this be 125, $50 or 200
miles an hour.