Improvements in or relating to Electric Railways and Tramways Worked on a Mixed Power System.
Year: 1899

page_text: Date of Application, 24th May, 1899
Complete Specification Left, 23rd Feb., 1900 - Accepted, 31st Mar.. 1900
PROVISIONAL SPECIFICATION.
Improvements in or relating to Electric Railways and Tramways
Worked on a Mixed Power System.
I, Dr. ERNST ANDREAS, Chemist, of Dresden, in the Kingdom of Saxony, do
hereby declare the nature of this invention to be as follows:
The present invention relates to an improved shunting device for mixed work-
ing (a combination of accumulator and line driving) for tramways or the like.
The invention is specially intended to be used in the automatic switch devices
forming the object of my prior Patent No. 17507 of 1898.
On lines of such an arrangement it often happens, when the potential differ-
ences are great or especially, that, when the line circuit is interrupted, the
accumulators arranged on the rolling stock have to provide not only for the line
current but also to feed other vehicles that happen to be on the line besides
providing the motive power on their own vehicle.
In consequence of this, great disadvantages arise as regards the regular working
of the line as the accumulators cannot be sufficiently charged during the voyage
from the line, and are prematurely or unduly discharged by providing current for
other vehicles, so that it often happens that when cars are expected to be worked
as automatic cars they cannot do so on account of a deficiency of current, or
because the accumulators have been already totally discharged. The shunting
device forming the object of the present invention is calculated to completely
remedy these evils.
In no case can undue charging or discharging of the accumulator battery take
place. The shunting device consists essentially of a shunting resistance and a
galvanic cell.
The magnet coil of an automatic shunter is located in the shunt circuit of these
two devices. For a better understanding of the effect of such an arrangement, it
should be observed that in a galvanic cell of this kind there are two electrodes
opposite each other, one being of aluminium and the other of any metal preferably
of lead or silver.
The electrolyte can be of any composition such as for instance a solution of
sulphate of magnesia.
A cell of this description possesses the well known property of allowing a current
to pass easily in one direction while a current in the opposite direction will meet
with a great resistance.
When the line circuit pole is positive and the collecter is connected with the
Jead electrode of the cell, while the positive pole of the accumulator is connected
with the aluminium electrode, the current passes without hindrance through the
cell and charges the accumulators. If however the direction of the current is
changed, as for instance when the tension of the accumulators is greater than the
line current, the cell will have a great resistance and at the two poles of the same
a potential difference of about 50 volts is produced, which will actuate the switch
in the shunting line, with the result that the accumulator circuit will be broken.

page_text: If, on the other hand, the charging on the part of the line current becomes too
strong, at the poles of the resistance of the shunt it may represent, for instance,
half an ohm, with a current of 100 amperes, a potential difference of 50 volts is
produced, which, as in the former case will excite the electro-magnet, and produce
thereby the shunting.
In this manner the discharge of current from the accumulators to the line or a
too strong charging of the accumulators from the line is rendered impossible.
The galvanic cell may also be placed in the shunt circuit with the electro-
magnet of the automatic shunter after it, instead of being located in the principal
circuit.
By means of such an arrangement the necessity is avoided of having the whole
accumulator current pass through the cell; since in consequence of such strong
currents passing through the cell the electrolyte is very rapidly decomposed, and
has therefore to be replaced very frequently.
Another drawback of the first arrangement is that the automatic shunter
is actuated at small differences as regards working; a circumstance which will
not he observable when the cell is located in the shunt circuit, inasmuch as such
differences are not so much felt in the latter.
Dated the 24th day of May 1899.
BOULT & WADE,
Agents for the Applicant.
Improvements in or relating to Electric Railways and Tramways
Worked on a Mixed Power System.
I, Dr. ERNST ANDREAS, Chemist, of Dresden, in the Kingdom of Saxony, do
hereby declare the nature of this invention and in what manner the same is
to be performed, to be particularly described and ascertained in and by the follow-
ing statement:
The present invent on relates to an improved shunting device for electric rail-
ways and tramways worked on a mixed power system (a combination of accumu-
lator and line driving).
The present invention is specially intended to be used in the automatic switch
devices torming the subject of my prior Patent No. 17507 of 1898.
On lines thus arranged it often happens when the potential differences
are great or fluctuate considerably and especially when the circuit line breaks,
that the accumulators have to provide cuiient also on the ordinarily line driven
parts and even to supply current to the line circuit either overhead or under-
ground to be used by other vehicles on the line.
The latter condition is particularly objectionable in cases when different parties
are making use of the same line current, or, where current producer and current
consumer are different parties.
Such loss, on the part of the accumulators of current on line driven tracks is.
moreover, very frequently followed by the annoying drawback, that when such
cars are expected afterwards to travel as automotors the current soon gives out,
the accumulators becoming totally discharged and the cars stop.
The shunting device torming the object of the present invention is calculated
to effectually remedy these drawbacks.
The new hunting device is described hereunder and schematically represented
in two positions in the accompanying drawing.

page_text: For the better understanding of the drawings the parts which are already
known from my prior patent are marked with the same reference letters. The
arrangement represented in both figures shows the shunting applied to line driven
movement; Figure 1 representing the circuit of the accumulator battery as inter-
rupted by the device forming the object of the present application, and Figure 2
the same closed.
The latter figure represents the shunting device in its normal condition during
the charging of the accumulators, while Figure 1 represents the device, forming
specially the object of the present invention, in action, such action being caused
by a back flow of the electric current from the accumulator battery to the line
circuit.
The novelty forming the basis of the present application consists, essentially,
in the arrangement of a resistance w and a galvanic cell bb in the circuit leading
from the line to the accumulator battery, in connection with a magnetic shunter s
arranged in the shunt circuit, which shunter s opens the current whenever the
current is reversed, i.e., whenever current flows back from the accumulator
battery to the line circuit.
In the accompanying drawing the principal circuit is represented in full lines
and the shunt circuit e in dotted lines. The galvanic cell consists of two elec-
trodes b b opposite to each other, the one being of aluminium and the other or
any other metal, but preferably of lead or silver.
The electrolyte may be of any suitable composition such as for instance a
solution of sulphate of magnesia.
A cell of this description possesses the well-known property of allowing the
current to pass freely in one direction, while a current in the reverse direction
will meet with great resistance.
The effect of such a cell in combination with the shunting device forming the
object of the present application, may be explained as follows:-
If the line circuit pole is positive and the collector a is connected with the lead
electrode 6 of the cell, while the positive pole of the accumulator d is connected
with the aluminium electrode b, the charging current will pass without hindrance
through resistance and cell 1 b to the accumulator. If, however, the direction
of the current is reversed, which will happen, for instance, when the potential of
the accumulators exceeds that of the line current, a strong polarisation will be
caused in the cell, in consequence of which a potential difference of about 50 volts
will be created, owing to which, the back flow of current from the accumulators,
meeting with a great resistance in the principal circuit, will pass through the
shunt circuit e, thereby energising the electro-magnet e and causing it to attract
the armature of the commutator or shunters in consequence of which the accu-
mulator circuit will be interrupted.
The commutator consists, in the construction represented in the drawings of a
bell-crank-lever, one end of which is provided with an armature s¹, and the other
with a hammer-shaped contact blocks, opposite to which is arranged a stationary
contact ².
Whenever the electro-magnet is energized by a backflow of current from the
accumulators as described above, the normal equilibrium is disturbed, the
armatures is attracted by the electro-magnet e and the contact s separated from
contacts, thereby causing the circuit of the accumulator battery to be interrupted.
Similar effects are produced, should the charge in the line circuit become
excessive. In this case and with a current strength of about 100 ampères a
potential difference of 50 volts will be produced at the poles of the resistance,
amounting to, say, half an ohm, which potential difference is sufficient to excite
the magnet as in the former case, and, thereby, to produce the breaking of the
circuit.
In this manner the discharge of current from the accumulators to the line and
a too strong charging of the accumulators from the line is rendered impossible.

page_text: Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
:-
a mixed
A shunting device for electric railways and tramways worked on
power system for the purpose of preventing an unintended discharge
of current during travelling. to the line circuit, whether overhead or under-
ground, and preventing overcharging of the accumulators, characterised by
the circuit for the charging current being arranged with a resistance (as w),
a galvanic cell and an automatic commutator actuated by an electro-magnet
arranged in the shunt circuit, in such manner that either in case of back
current or excessive potentiality in the line current, the accumulator battery will
be shunted out of the circuit, substantially as described.
Dated this 23rd day of February 1900.
BOULT, WADE, & KILBURN,
Agents for the Applicant.