Improved Means for Operating Electric Railways by a Combination of Alternating and Continuous Currents.
Year: 1898

page_text: Improved Means for Operating Electric Railways by a Combination
of Alternating and Continuous Currents.
I, CHARLES POLLAK, of 2538, Mainzerlandstrasse, Frankfort-on-the-Main, in
the German Empire, General Managing Director, do hereby declare the nature
of this invention to be as follows:-
Continuous currents are at present best suited to the working of electric rail-
ways, while the transmission of the electrical energy to points situated at great
distances is better accomplished by means of a high-pressure alternating current
with transformers. The present invention relates to a combination of the two
systems, as hereinafter described, whereby electric railways are better fitted
for long-distance traffic.
In carrying out this invention the high pressure alternating current is con-
verted either in the motor carriages or at the several sub-stations into low-
pressure current which in the carriages-each of which carries along with it
suitable apparatus which I term an equalizer for converting alternating currents
into continuous currents, say a device of the class described in the British
Patents Nos. 24398 of 1895 and 23442 of 1897 is transformed into continuous
current for the purpose of feeding the motors and batteries.
In the following description the apparatus employed for changing the alter-
nating currents are alone referred to as transformers, whereas the devices serving
to convert alternating current into constant or direct current are referred to as
equalizers.
Referring to the accompanying drawings in the arrangement shewn in Figure 1
the alternating current passes from the conductor m through the contact a into
the primary coil of a transformer placed in the carriage g, and from this point
passes off to the earth or return-wire n. In the secondary coil low pressure
alternating current originates which is conducted into the electrolytic equalizer d
and is there given a constant or continuous direction for the purpose of feeding
the battery and motor f.
The switch-devices have all been omitted from the drawings to avoid confusion.
Figure 2 shows a modified arrangement wherein the conversion of alternating
urrent at high pressure, say 5000 volts, into a 300 volt current is effected in
stationary transformers such as o, p, and where the low pressure current is con-
ducted to the sections 99 of the working conductor and to the return-wire r.
The carriage g is in this case provided with one electrolytic equalizer only,
o convert the alternating current into constant current and to supply the bat-
ery e and motor f. It may be here mentioned that the provision of a battery
uch as e is not in all cases necessary.
Figure 3 illustrates the conversion of alternating current in two phases-first
conversion in the transformer o, p, into medium pressure current, say from

page_text: 5000 volt to 500 volt, and then, in the carriage g itself-the conversion taking
place in the transformer bc and in the equalizer d, as previously described.
Dated this 25th day of June 1898
JOHNSONS & WILLCOX.
47, Lincoln's Inn Fields, London, W.C., Agents.
Improved Means for Operating Electric Railways by a Combination
of Alternating and Continuous Currents.
I, CHARLES POLLAK, of 253, Mainzerlandstrasse, Frankfort-on-the-Main, in
the German Empire, General Managing Director, do hereby declare the nature
of this invention and in what manner the same is to be performed to be particu-
larly described and ascertained in and by the following statement:-
Continuous currents are at present best suited to the working of electric rail-
ways while the transmission of the electrical energy to points situated at great
distances is better accomplished by means of a high-pressure alternating current
with transformers. The present invention relates to a combination of the two
systems, as hereinafter described, whereby electric railways are better fitted
for long-distance traffic.
In carrying out this invention the high-pressure alternating current is trans-
formed into low pressure current either in the motor carriages or at the several
sub-stations each of which motor carriages carries suitable apparatus which is
termed rectifier for converting alternating currents into continuous currents (say
a device of the class described in the British Patents Nos. 24398 of 1895. 23442
of 1897 or 933 of 1898) for the purpose of feeding the motors and batteries.
In the following description the apparatus employed for changing the pressure
of the alternating currents are referred to as transformers, whereas the devices
Berving to convert alternating current into continuous or direct current are
referred to as rectifiers.
Referring to the drawings accompanying the Provisional Specification Figure 1
illustrates an arrangement wherein the alternating current passes from the con-
ductor m through the conduct a into the primary coil of a transformer placed
in the carriage 9 and from this point passes off to the earth or return-wire n.
In the secondary coil e flows low pressure alternating current which is conducted
into the electrolytic rectifier and is there given a constant or continuous direc-
tion for the purpose of feeding the battery and motor f.
The switch devices have all been omitted from the drawings to avoid confusion.
Figure 2 shows a modified arrangement wherein the conversion of alternating
current at high pressure, say 5000 volts, into a 300 volt current is effected in
stationary transformers such as o, pand where the low pressure current is con-
ducted to the sections ag of the working conductor and to the return-wire r.
The carriage is in this case provided with one electrolytic rectifier & to con-
vert the alternating current into constant current and to supply the battery e
and motor f. It may be here mentioned that the provision of a battery such
as is not in all cases necessary.
Figure 3 illustrates the transformation of alternating current in two steps
first in the transformer o. r. into medium pressure current say from 5000 volt
to 500 volt, and then in the transformer be placed in the carriage g into low
pressure alternating current of say 100 volts which is finally converted into
direct current by means of the rectifier d.

page_text: I do not limit myself to the arrangement or combination described, as similar
or equivalent combinations may be used for the purpose described without
departing from the nature of my invention, but having particularly described
and ascertained the nature of my invention what I claim is:-
:-
1. Means for operating electric railways characterized by a combination of
alternating and direct or continuous currents the alternating current. being taken
from a long distance, or a working conductor. and converted into direct or con-
tinuous current by electrolytic or mechanical rectifiers placed in the carriages
substantially as hereinbefore described.
2. Means for operating electric railways characterized by the combination
described in the 1st Claim wherein the high pressure alternating current is trans-
formed to low pressure by transformers and then into direct or continuous current
By rectifiers both being placed in the motor carriage substantially as herein before
described.
3. Means for operating electric railways. characterized by the combination
described in the 1st Claim wherein the high pressure alternating current is con-
verted to low pressure by stationary transformers serving to supply sections or
parts of the working conductor, and transforming the said current into direct
or continuous current by means of rectifiers placed in the carriages substantially
as hereinbefore described.
4. Operating electric railways by means of a combination of alternating cur-
rents and direct or continuous current by the transformation of the alternating
current in several steps. by means of stationary transformers placed in sub-
stations. and transportable transformers in the carriages, and transforming the
alternating currents into direct or continuous current by rectifiers placed in the
carriages, substantially as hereinbefore described.
Datel +1: our 1
JLJ
1000
JOHNSONS & WILLCOX.
47, Lincoln's Inn Fields, London, W.C., Agents.