Improvements in Preventing Sparking when Making and Breaking Electric Circuits.
Year: 1898

page_text: Date of Application, 5th Jan., 1898
Complete Specification Left, 1st Oct., 1898-Accepted, 17th Dec., 1898
PROVISIONAL SPECIFICATION.
Improvements in Preventing Sparking when Making and Breaking
Electric Circuits.
We, ADOLPH MÜLLER, of 90, Bergstrasse, Hagen, Westphalia, in the German
Empire, Works Director, and HENRI TUDOR, of Rosport, in the Duchy of Luxem-
burg, Engineer, do hereby declare the nature of this invention to be as follows;-
:-
This invention relates to improvements in preventing sparking when making
and breaking electric circuits, the said improvements being applicable to all kinds
of making and breaking devices and particularly to the transforming of electric
currents by means of switches or commutators and secondary batteries.
In such arrangements as hitherto used for the above mentioned purposes there
exists the unavoidable disadvantage of strong and injurious sparking which often
very seriously affects the life of the switch apparatus.
Now this disadvantage is effectually overcome by our invention which we
will now proceed to describe:
If a secondary battery be connected with the circuit of a dynamo so as to be
charged thereby, then the circuit can be broken without the formation of sparks
by altering the electromotive force of the battery or accumulator by switching in
more cells, in such a manner that the difference of potential between the poles of
the battery is made the same as that of the dynamo. When this condition is
obtained the circuit has no current flowing through it and it can be broken without
the formation of sparks.
Any circuit in which an electromotive force is opposed to that of the current
source can be broken in a similar manner without sparking by increasing the
opposing electromotive force until it equals that of the source of current before
breaking the circuit.
This is effected according to this invention by introducing into the circuit
before disconnection a battery of elements which are of small capacity and easily
become polarized. Elements suitable for this purpose are for instance those con-
sisting of steel plates immersed in a potash solution, platinum plates in sulphuric
acid, plain lead plates in sulphuric acid or aluminium plates in an alum solution.
Such a battery is immediately polarized on entering the circuit to the tension of
the current in the said circuit or it immediately increases any opposing electro-
motive force which may be present in the circuit until it is equal to that of the
source of current so that current no longer flows through the circuit which can
therefore be broken without sparking.
For transforming continuous currents at a certain tension into continuous currents
at a different tension and also for transforming alternating currents into continuous
currents and vice versa, we introduce into the circuits, before each interruption or
break thereof, a polarization battery in series with the current source and the
consumption apparatus (secondary battery. etc).
For interrupting or breaking polyphase currents without sparking, it is necessary

page_text: to introduce several polarization batteries into the circuit. For example, before
interrupting three phase current circuits, such batteries must be introduced into
two of the three circuits in the manner hereinbefore described.
The polarization battery can in many cases be replaced by a condenser, the
dimensions of which must be suitably calculated.
For the purpose of our invention any suitable switch or commutator device can
be employed it being only necessary that a polarization battery, before each inter-
ruption or breaking of the circuit, be connected up in the circuit in series with
the current source and the consumption apparatus, the said battery being designed
to become polarized sufficiently quickly to a tension which shall reduce the electro-
motive forces in the circuit to zero.
Improvements in Preventing Sparking when Making and Breaking
Electric Circuits.
We, ADOLPHI MÜLLER, of 90, Bergstrasse, Hagen, Westphalia, in the German
Empire, Works Director, and HENRI TUDOR, of Rosport, in the Duchy of Luxem-
burg, Engineer, 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 following statement:-
This invention relates to improvements in preventing sparking when making
and breaking electric circuits, the said improvements being applicable to all kinds
of making and breaking devices and particularly to the transforming of electric
currents by means of switches or commutators and secondary batteries.
In such arrangements as hitherto used for the above mentioned purposes there
exists the unavoidable disadvantage of strong and injurious sparking which often
very seriously affects the life of the switch apparatus.
Now this disadvantage is effectually overcome by, my invention which I
will now proceed to describe by reference to the accompanying drawings, in
which:-
Figures 1 to 5 are diagrammatic views of electric circuits provided with our
improved means for preventing sparking;
Figure 6 is a similar view but shewing the development of the commutator.
If a secondary battery A be connected with the circuit of a dynamo 1) (Figure 1)
so as to be charged thereby, then the circuit can be broken without the formation
of sparks by altering the electromotive force of the battery or accumulator by
switching in more cells, for instance by turning the lever s of a switch Z.to the
right, in such a manner that the difference of potential between the poles of the
battery is made the same as that of the dynamo. When this condition is obtained
the circuit has no current flowing through it and it can be broken without the
formation of sparks.
Any circuit in which an electromotive force is opposed to that of the current
source can be broken in a similar manner without sparking by increasing the
opposing electromotive force until it equals that of the source of current before
breaking the circuit.
This is effected according to this invention by introducing into the circuit
before disconnection a battery of elements which are of small capacity and easily

page_text: become polarized. Elements suitable for this purpose are for instance those con-
sisting of steel plates immersed in a potash solution, platinum plates in sulphuric
acid, plain lead plates in sulphuric acid or aluminium plates in an alum solution.
Such a battery is immediately polarized on entering the circuit to the tension of
the current in the said circuit or it immediately increases any opposing electro-
motive force which may be present in the circuit until it is equal to that of the
source of current so that current no longer flows through the circuit which can
therefore be broken without sparking.
If, for instance, the current from a dynamo D, Figure 2, serves to charge a
secondary battery or accumulator A, the circuit can be broken without sparking
occurring by introducing a polarization battery P into the said circuit. This
can be effected, for instance, by means of a switch U the contact lever a of which
covers two contacts c', 2 of which the one c¹ is in connection with the one pole of
the dynamo D) and the polarization battery, the second being connected to the
other pole of the polarization battery whilst the contact lever h forms the second
pole of the circuit from the dynamo D.
If, now, the lever h be turned, from the position shewn in the figure, in which
position the current flows directly from the pole of the dynamo through the con-
tact to the lever h, to the right then as soon as the said lever leaves the
contact cl, the polarization battery P will be connected up in front of the accumu-
lator or secondary battery A. The battery P is then immediately polarized to a
tension which reduces to zero the sum of the electromotive forces of the battery A
and of the current source so that the flow of the current is stopped. If the contact
lever h of the switch U be turned still further to the right then at the moment
when the lever leaves the contact c² the breaking of the circuit is effected with-
out the occurrence of sparking from extra current as all portions of the circuit are
without current.
The breaking or interruption of a circuit, with which an electro-motor is con-
nected and driven from the current source D, is effected in an exactly similar way
by means of a similar device (Figure 3). The lever h can in this arrangement
be shifted from the contact by a single movement so that the breaking of the
circuit is effected whilst the motor M. still rotates as a consequence of its momentum
and thereby generates a certain electromotive force. If such should not be the
case the polarization battery P must, before the breaking of the circuit, be
polarized to the terminal potential of the current source in order to effect the
breaking of the current without the formation of sparks; the polarization battery
must, therefore, be formed of a sufficiently large number of elements.
In those cases also wherein an opposing electromotive force is not introduced
into the circuit (for instance in simple light installations) the interruption of the
circuit can also be effected without sparking by my invention.
For example, when it is desired to switch off a number of arc lamps L (Figure 4)
by means of such a device, then as soon as the contact lever touches the contact 2,
so that the battery D is introduced into the circuit the battery P is polarized to
the terminal tension of the current source D whereby the circuit can be interrupted
or broken without sparking by further turning the lever h.
For transforming continuous current of low tension into high tension current
the invention can be advantageously employed as illustrated diagrammatically in
Figure 5.
This application rests generally upon the known arrangement of charging, by
means of the dynamo machine, the separate groups a¹, a², a³, a', of a high tension
battery A in their proper sequence whilst at the same time current is obtained from
the poles of the said high tension battery, the tension of the current
obtained being approximately as many times that of the charging current as there
are groups in the high tension battery.
For charging the groups a¹, a², a³, as the poles c³, c², c³, c, c³ of each group are
successively connected to the poles cl, c¹³ of the dynamo D the connection being
successively broken and made with the next group.

page_text: Now, in order that at each disconnection of a battery group from the dynamo for
the purpose of connecting up the next battery group thereto no current shall flow
in the circuit to be broken, a small polarization battery P is introduced, before
disconnecting the said battery group, into the charging circuit in front of the said
battery group. This is effected as shewn in the accompanying diagram (Figure 5)
by turning to the right the switch lever h which, when the polarization battery P
is not in the circuit, connects the contact c3 which is in connection with one pole
of the dynamo to the contact ca the said lever being brought into contact with
the contact c¹. In order not to break the circuit whilst this operation is being
effected the contact lever h must be over the insulating space or slit between the
two contacts c³, c¹. If the polarization battery P is connected with the circuit the
latter is without current and can therefore be disconnected without the formation
of any sparks.
The same arrangement can also be employed for introducing the battery
groups a, a, a, a into the circuit without sparking. To this end it is only
necessary to connect up the polarization battery in front of the battery to be
introduced into the circuit before switching in the said battery
•
The cells of the polarization battery are so chosen that the battery A receives
no current at the moment of connecting up whereby the battery B at this instant
receives the whole of the current from the generator D. Furthermore the number
of cells in the battery B is made somewhat greater than that of the separate groups
of A lying between the terminals so that the battery B at the time the charging
current flows through the particular group of cells A not only receives current
but can also give up to A the quantity of electricity received during the switching
operation.
The described arrangement can also be utilized in a similar manner for trans-
forming currents of high tension to currents of low tension; in this case also the
polarization battery P must be so introduced into the circuit that its electromotive
force counteracts the electromotive forces at work in the circuits.
The switching operations are in practice not effected by means of the arrange-
ment illustrated diagrammatically in the drawing but preferably by a mechanically
operated, for instance a revolving switch or commutator in such a manner that
the various operations are automatically carried out in their proper sequence.
The constructional details of such a switch will offer no difficulties to experts and
can be carried out in various ways so that there is no necessity to particularly
describe an example thereof.
Our invention can also be used for interrupting or breaking alternating currents
as polarization batteries of this kind can be given such a small capacity that the
condition of their charge can follow the change in the electromotive force of the
current source quickly enough to, at any moment, bring the sum of the latter and
of the opposing electromotive force of the consumption apparatus to zero and to
thereby stop the flow of current.
In order to transform an alternating into a continuous current by utilizing this
method a switch device preferably of the kind diagrammatically illustrated in
Figure 6 is employed.
In this arrangement conductors 11, 12 extend from the alternating current
dynamo W to two brushes E', E2 which slide over the contacts b, 62, 63, 64, 65
of a drum-shaped commutator, shewn in development in the figure, when the
said commutator is rotated by a motor revolved synchronously with the alternating
current dynamo. The contacts 61, 62, 63, 64, 65 are separated from one another by
insulating slits the contacts 61, 63, 65, being connected to the ring and the other con-
tacts 62, to the ring as shown. Current collecting brushes D1, D2 slide upon the
rings d, d², the said brushes being connected by conductors g¹, g" to a secondary battery
or accumulator G. The commutator, which rotates synchronously with the alter-
nating dynamo, has for its object to disconnect the accumulator & from the charg
ing dynamo at that moment in the phase of the alternating current at which the

page_text: tension of the alternating current drops below that of the battery, and by changing
the poles to again connect it to the dynamo at the instant in the next half of the
current phase when the tension of the alternating current commences to exceed
that of the battery.
Such commutator devices are known and do not form part of this invention.
It is, however, also known that such commutators, as also those employed for trans-
forming continuous currents, possess the disadvantage that the moment when the
tension is equal is never exactly hit upon so that when disconnecting there is very
often a great deal of sparking at the commutator which soon injuriously affects
the latter.
According to this invention in order to avoid this disadvantage, a polarization
battery P is introduced into the circuit each time before the latter is interrupted
or broken. This can be effected by arranging intermediate contacts 612, 64, 650 in
the insulating slits, which said intermediate contacts are connected with a ring fl
by insulating wires f. Upon this ring f¹ there slides a brush F' which is in
connection with one pole of a polarization battery P composed of elements of very
small capacity, the other pole of the said battery being connected with a brush F³
which slides upon the ring d.
and vice versa.
The intermediate contacts 612, 634, 656 are separated from the above mentioned
contacts 61, 63, 65 by a narrow insulating space which is covered by the brush E¹
or E2 which bridges it so that the said brush only leaves the contacts 61, 63, 65 when
it has made contact with the intermediate contacts 612, 634, 656. The second brush E⁹
when the
is so arranged that it only leaves the adjacent contact 62, 65.
brush E has left the contact b¹
With this arrangement whilst the commutator drum is synchronously rotating,
the battery P is introduced into the circuit shortly before the brushes E¹, E³
break the contact between the dynamo, the brushes D1, D2 and the battery G by
leaving the contacts 61, 63. ; this being effected by one of the contacts 62, 634,
656 (for instance 612) coming into contact with one of the brushes E¹,E2, (for in-
stance E¹) whilst the other of the two brushes remains in contact with the next
following or the next preceding one of the contacts 61, 62 (for instance 62) until
the other brush has left the contact (for instance 61) next to the corresponding
intermediate contact (for instance 612). The battery P is, therefore, at this instant
connected up in front of the battery G and in consequence of its small capacity
will be practically instantaneously charged to a tension which increases the opposing
electromotive force of the battery G to such an extent that the said electromotive
force becomes exactly equal to the momentary tension of the alternating current
so that the circuit of the dynamo w is without current. If, now, the dynamo w
be disconnected by shifting the brush (E¹) from that one of the contacts b¹,
with which it has remained in contact, then no sparking can take place.
1,2
For transforming continuous currents at a certain tension into continuous currents
at a different tension and also for transforming alternating currents into continuous
currents and vice versa we introduce into the circuits, before each interruption or
break thereof, a polarization battery in series with the current source and the
consumption apparatus (secondary battery etc).
For interrupting or breaking polyphase currents without sparking, it is necessary
to introduce several polarization batteries into the circuit. For example, before
interrupting three phase current circuits, such batteries must be introduced into
two of the three circuits in the manner hereinbefore described.
The polarization battery can in many cases be replaced by a condenser, the
dimensions of which must be suitably calculated.
For the purposes of our invention any suitable switch or commutator device can
be employed it being only necessary that a polarization battery, before each inter-
ruption or breaking of the circuit be connected up in the circuit in series with
the current source and the consumption apparatus, the said battery being designed
to become polarized sufficiently quickly to a tension which shall reduce the electro-
motive forces in the circuit to zero.

page_text: 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. Improvements in preventing sparking when making and breaking electric.
circuits, such improvements consisting in introducing into the circuit before making
or breaking it, a polarization battery formed of elements of small capacity or a
condenser or the like in series with the current source and the consumption
apparatus for the purpose of stopping the flow of current in the said circuit before
the making or breaking thereof, substantially as hereinbefore described.
2. The employment of the method for preventing sparking described in Claim 1,
for commutator devices, switches or the like operated mechanically or by hand
and which serve for transforming electric currents, substantially as hereinbefore
described.
3. An arrangement for carrying out the method described in Claim 1 in the
transformation of continuous current into continuous current of different tension
by means of a commutator and secondary batteries, such arrangement consisting in
introducing into the circuit shortly before the commutator breaks it, a polarization
battery P (Figure 5) or the like in series with the source of current D and the
battery (a) at the time to be charged, substantially as herein before described and
illustrated.
4. The arrangement for carrying out the method described in Claim 1 in the
transformation of alternating into continuous current by means of a commutator
device which is operated synchronously with the alternating current, consisting in
introducing into the circuit shortly before each break thereof by the commutator,
a polarization battery P (Figure 6) or the like in series with the alternating
current source (M) and the consumption apparatus (secondary battery G etc.)
substantially as described and illustrated.
ז
1000
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.