New-York tribune., 1901-11-24
THE BERLIN-ZOSSEN TESTS
NOVEL EXPERIMENTS IN ELECTRIC
TRACTION
MANY QUESTIONS RAISED BY THE ATTEMPT TO
Use ALTERNATING CURRENTS

MANY QUESTIONS RAISED BY THE ATTEMPT TO
Use ALTERNATING CURRENTS
The tests which have been in progress for sew
eral weeks short electric road from Berlin
to Zossen popularity supposed TO have been
undertaken chiefly for the purpose of ascertain
ing how high speed is practicable This Ii a
mistake. velocties depend more largely on a
straight well built track than the motive power
employed With steam OF the methods already
in use in electric traction hundred or one
hundred and twenty-five miles an hour could
easily be made if the road properly con-
structed-
A much more important question is involved
in the German experiments than one of speed.
interesting the latter is They are designed
to ascertain the feasibility of using an alternat-
ing current of high voltage, instead of direct
current of low voltage, for the operation Of cleo
trio cars Up to the present time. practically all
the world it is the continuous current which
drives the trolley car. and these run at a press
ure of about five hundred volts A highly revo-
lutionary idea is therefore trial
1t was long ago discovered that If electric
energy be sent for long distances over a
copper wire a high voltage would require less
metal than low one. Moreover. if voltage is
to be transformed upward for transmission pur-
poses and then down again for service, an alter
mating current is essential You cannot do that
Railway Company, for instance, viii generate its
electricity at a pressure of IL 900 volts trans
nit it at the same, but it at 600 or 625 volts
And this plan makes it necessary to have alter
mating current dynamos and sub-stations close
to the tracks at which the two operations OF
reducing the voltage and converting the current
from the alternating type to the direct type can
be conducted. Now both operations involve the
| installation of costly apparatus and a certain
1
version These could be avoided if the alternat-
ing current could be applied to the motors just
as it came from the power house But voltages
of ten thousand and twenty thousand are so
dangerous when there is a chance that people
or property may accidentally encounter them
that the champions of the alternating current
are disposed to make reduction OF the
pressure if they can only escape the necessity
for converting into direct current.
The most important ventures yet made
with alternating currents on railroads are those
] undertaken in Northern Italy and in Germany
/ A system of old steam roads in the vicinity OF
| Lake Como embracing a total length of sixty
seven miles has been equipped by a famous
Budapest firm. CAM & Co, with alternating ap-
| paratus and was TO have been in operation this
| last summer. For some reason, however, the
work there has not made such rapid progress
| was anticipated. and the promised demonstra-
/ ton has not been afforded There has been a
| determined struggle in London between the
! champions of the Ganz system and the direct
current system for the control of the old Metro
| poIitun and District underground steam roads,
| and this has hinged TO some extent upon the
/ outcome of the Italian tests, which have been
| delayed.
In the mean time company has been organ
| lied in Germany for experiments in traction,
| and a short military road. hitherto operated by
steam, has been put at their disposal The full
| distance from the capital to the southern ter
| minus, Zossen. is 1876 miles But the portion
| of the track devoted to the tests begins at
| Marienfelde. not Berlin. and is only 142o miles
| in length. While two big manufacturing houses.
| the General Electric and Siemens & Holske.
| have built and equipped the cars. one general
| plan has been pursued. which 0lIers IN several
| details from that Of Ganz & Co, in Italy
The favorite system Of generating and trans
! mitting alternating currents nowadays Is 10
( have three distinct currents whose waves over
| lap each other at equal intervals. Hence, three
| conductors are needed When the electricity IS
| merely being sent from one point TO another
three insulated cables bound up in one can be
| employed. But when the current is TO be ap-
| piled the conductors must be separated Thus
| in Italy there are two overhead wires, side by
side and one line of rails performs the junction
| of the third. On the Observation-Disclosures ROAD
| three overhead wires are used. arranged one
above another. In Italy the current can De
| taken off by horizontal roller, long enough to
| press up against the two wires, and carried oy
| poles each side of the car In Germany there
| is but one pole. with separate trolley Wneels for
each OF the three wires
Another point of difference lies In the voltages
and the methods Of reducing them In Italy the
| current is generated at twenty thousand volts,
transmitted that pressure TO ten Sub-Stations.
/ there transformed TO three thousand VOLTS ana
I led through overhead wires into the car motors
\ The German plan is to develop a voltage OF ten
thousand or twelve thousand at the power
house maintain this in the overhead wires and
/ put the Transforming apparatus under the car