Improvements in Electric Mountain Railways.
Year: 1897

page_text: Date of Application, 28th May, 1897-Accepted, 18th Sept., 1897
COMPLETE SPECIFICATION.
Improvements in Electric Mountain Railways.
We, EMIL ANDRE, of 15 Thiergarten Strasse, Hannover Engineer and ALBERT
SILBERMANN, of 74 Blumenstrasse, Berlin, Manufacturer, do hereby declare the
nature of our said invention and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement:-
The present invention relates to electric mountain railways and consists of
a device for controlling the electro-motor of the car so as to enable the same to
generate a counter current in the circuit during the downward passage of the car,
without, however, unduly increasing the speed of the said car, the device further
operates to cause the motor to act as a brake during its downhill passage.
Since in order to produce a counter current in the circuit the electromotive
force of the dynamo must exceed that in the line wires, the cars were hitherto
allowed to run downhill at a higher speed, in order to increase the electromotive
force of the dynamo-for as such the motor operates under the circumstances-
hy increasing the number of revolutions of the same. An increase of the speed
of the car downhill increases the danger very considerably so that hitherto the
system of regenerating the current during the downhill passage has generally
been avoided on this score.
According to the present invention the increase of speed of the electromotor
when acting as a dynamo is attained without increasing the speed of the car by
means of a device for changing the gearing connecting the car wheels or axle
with the motor. The invention may be applied to all kinds of electric cars,
whether, driven by contact with overhead or underground conductors, or by
accumulators.
And in order to render the present specification more easily intelligible
reference is had to the accompanying drawing in which similar letters of
reference denote similar parts throughout the several views: -
Fig. 1 is a front elevation partly in section of one form of the invention,
Fig. 2 a vertical section on line ee of Figure 1,
Fig. 3 a similar section on line f-f of Figure 1,
Fig. 4 a side elevation of the gear shifting arm,
Fig. 5 a diagrammatical representation of a modified form of the invention
showing the electric connections and position of the parts during the upward
journey and
Fig. 6 a similar representation during the downward journey.
Referring to Figs. 1 to 4:-A sleeve H is mounted on one of the axles said
sleeve being keyed to the said axle by means of a key K and being moveable
thereon in the direction of the longitudinal axis of the same. The sleeve H
carries two gears a and b of different diameters and pinions c and d are mounted
on the driving shaft of the motor M, one of the said pinions being in engagement' with
one of the gears a or b. The gears a and b and the pinions c and d are so mounted
on their respective shafts that when the gear a is engaged by the pinion c, the
gear b and pinion d are out of engagement and vice versa. In the drawing, when
a and c mesh, the pinion d is idle and lies between the two gears a and b, but

page_text: it will be evident that the wheels may be mounted so that the idle pinion may
lie outside the gears. The sleeve H is provided with a groove N in which the
straps R of a rod A engage, so that by moving the rod A the gears must be
shifted.
The gears and pinions are advantageously of such diameters as to cause the motor
shaft to make twenty per cent. more revolutions when the wheels band d are
in engagement than when a and c mesh.
During the upward journey will engage a whilst on the downward journey,
the lever A is thrown over and the gears band d brought into engagement. The
impetus of the car during the downward journey causes the motor M to act as a
current generating dynamo and consequently as a brake. The increased speed
of the armatures of the motor will generate an increased current so that the
motor will operate to feed current to the conductors, whilst the speed of the car
will remain unaltered.
The same effect may be obtained by electrical means according to the device
shown at Figures 5 and 6.
Each car is provided with two dynamos, one of which is larger than the
other d, the latter acting as a brake and being termed the "brake dynamo" for
the purposes of the specification. Both dynamos may be mounted on one and
the same shaft, but it is generally better to have them on separate shafts.
During the downward journey the brake dynamo is switched out of the circuit (Fig. 5)
the current being fed to the motor from the overhead conductor a passing
through the motor to the return line 6. During this journey the brake
dynamo runs idle i.e., it has no effect.
During the down journey the brake dynamo is switched in, being connected
up with the motor in series (Fig. 6). Both machines now operate to brake me
car and as current generating dynamos, or more correctly speaking as electro-
motors driven by the impetus of the car. If the machine only were employed,
the current regained would be converted into heat by the resistance, but by
switching in the dynamo d¹ its tension is added to that of the machine c¹ and the
surplus of electric energy thus attained is returned to the conductors.
It will, of course, be understood that the pole of the machine is not changed
during the down journey, the arrangement shown at Figure 6 being employed,
so that the pole remains unaltered.
Other devices, besides that just described may be employed for the same
purpose, such devices being superficially mentioned in the following paragraphs.
Thus for instance if two or more motors are on the car, the same may be
connected up parallelly during the up journey and in series during the down
journey so that in the latter case the tensions of the several machines will be
added together and the sum of the same become effective.
The magnetic field may be influenced in the known manner to attain the
required tension by means of suitable resistances in shunt connection with the
series windings of the field magnets, or by means of shunt windings which
counteract the series windings.
Instead of employing two machines, the armature of one machine may be
provided with two different windings and correspondingly with two collectors.
During the down journey the windings would be connected up in series whilst
during the up journey, the same would be connected up parallelly by means of
the collector brushes so that in this case too the sum of the tensions will be
effective.
In the case of multiple pole dynamos the increase of tension may be added by
rendering operative or inoperative certain of the field magnets and adjusting
the brushes accordingly. Thus, for instance, in a six pole dynamo, if two of the
fields are rendered inoperative during the up journey, the brushes being adjusted
accordingly, and operative during the down passage, the tension will be increased
by one-third during the latter journey.
The above devices for increasing the tension of the dynamo may be easily

page_text: applied and enable the regaining of from 40 to 60 % of the electric energy, as
has been proved by experiments with elevators.
In view of the considerable amount of electromotive power employed in con-
nection with mountain railways, it will be clear that considerable saving will be
effected by the present invention.
Thus in the case of the Jungfraubahn, instead of the 1500 to 2000 1.1. estimated,
only 900 to 1200 would be required whilst the section of the conductors and the
whole cost of the plant would be considerably reduced.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is:-
1. In an electric mountain railway (railway with inclines) a device for
increasing the tension of the dynamo during the down journey without danger-
ously increasing the speed of the car, which consists of a device in connection
with the motor enabling the latter during the down journey, and irrespective of
the kind of current employed, to act as a dynamo and impart current to the line
wires by increasing the number of revolutions of the said motor, said motor
acting simultaneously as a brake substantially as described.
2. A device according to Claim 1 characterized by an additional dynamo,
adapted to be connected up with the motor in series during the down journey
in order to increase the tension of the latter by means of its own tension, and
simultaneously to act as a brake, substantially as described.
Dated this 28th day of May. 1897.
BOULT & WADE,
Agents for the Applicant.
BOULT & WADE,
Agents for the Applicant.