Improvements in Transforming Continuous Electric Currents.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in Transforming Continuous Electric Currents.
We, ADOLPH MÜLLER, of 90, Bergstrasse, Hagen, Westphalia, in the German
Empire, Director, and HENRI TUDOR, of Rosport, in the Grand Duchy of Luxem-
bourg, Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to improvements in transforming continuous electric cur-
rents by means of accumulators or secondary batteries.
To transform a continuous current of a given tension to a current of a different
tension by means of accumulators or secondary batteries it has hitherto been cus-
tomary, when it is desired to transform a high-tension current into a low-tension
current, to arrange the elements in series for charging and in parallel for dis-
charging and when it is desired to transform a low-tension current into a high-
tension current to proceed in the opposite manner, that is to say, to arrange the
elements in parallel for charging and in series for discharging. With this arrange-
ment continuous working can only be obtained by employing two separate
batteries of full capacity, the said batteries being alternately charged and dis-
charged so that the process is thus made expensive.
Endeavours have been made to obviate this disadvantage by employing a com-
mutator, which successively connects the groups or series of the single battery
employed with the charging or discharging-circuit such an arrangement has
been described in the United States Specifications Nos. 565740 and 565741.
In these arrangements, to obviate the interruptions of the current attending
the operation of the commutator, the brushes are made of such a width, that they
completely cover the insulating segments when passing over them so that each
group of the battery elements or cells is unavoidably short circuited by the com-
mutator brushes thereby giving rise to disturbances which prevent the arrange-
ments answering in practice.
If, as is mentioned in the American patent the insulating segments are, in order
to avoid the short-circuiting of the whole battery, made of such a width that tho
brush does not completely cover them, the circuit is completely broken and the
current interrupted so that powerful sparking takes place at the commutator,
which sparking also prevents the efficient working of the arrangement.
In the German Patent No. 50056 also an arrangement is described whereby
the transformation of a current is effected which although for another purpose.
is still in one sense a continuous current transformation.
In this case the complete interruption of the charging current is avoided by
the introduction into the circuit of a shunt which can consist of a resistance coil
or of accumulators. If accumulators be used they must, as in the case of the
single groups which are to be charged, be constantly disconnected and replaced
by others. This would make the complicated connections necessitated by the
disconnection of the single battery groups from the discharging-circuit, still more
complicated, as in order to charge one group of accumulators four groups would
have to be reversed or have their connections altered.

page_text: Furthermore with this arrangement it is only possible to transform a low-ten-
sion current into a high-tension current, the reverse, that is to say, the transforma-
tion of a high-tension current into a low-tension current not being possible.
Now this invention relates generally to means for transforming continuous
currents at any tension into currents at any desired higher or lower tension. The
chief object of the invention is to employ a current, transformed by means of
storage batteries or accumulators to transmit electrical energy from a current
generator or source of current to a distance by means of conductors of small cross-
section and to render it utilizable at its destination, as also to convert a continuous
current of any given tension into a continuous current of any other desired tension
to be used in conjunction with the same source of current.
According to the invention the transformation of the current is effected without
any interruption of the currents flowing through the charging and discharging-
circuits and without the possibility of even a momentary short-circuiting through
the commutator brushes taking place. Furthermore the arrangement enables the
regulation of the current used to be suitably effected without the employment of
any switch devices other than those generally known in connection with accumu-
lators or secondary batteries.
.
This is, as opposed to the arrangements described in United States Specifi-
cations Nos. 565740 and 565741, effected by introducing between the two con-
ductors or leads of the low-tension current a second accumulator or secondary
battery of the same electro-motive force or tension as the said circuit. This
battery takes no part in diverting or reversing the current but has for its object
to equalize the differences of potential arising from the interruptions of the
current caused during the change of connections.
In carrying out our invention the source of current or the generator has pro-
ceeding from it two conductors or leads between which an equalizing accumulator
or secondary battery is introduced and which pass to the brushes of a commu-
tator, the contact rings of which are continuously rotated by means of a small
electro motor. The rotating rings carry inner brushes in contact with a fixed com-
mutator and the contact segments of the commutator, which segments are separated
by broad or thick insulating segments, are connected by conductors to an accumu-
lator or secondary battery which consists of a corresponding number of groups or
series of cells. The two extreme conductors are connected to the two ends of the bat-
tery and the others to the connections between the separate groups of cells. By
means of the said connections the groups are arranged in series and can therefore be
discharged by the wires or connections secured to the ends of the battery at a
tension the increase in which depends upon the number of groups employed.
The generated current passes from the generator, in one position of the inner
brushes, through one of the conducting wires, a commutator brush, rotating ring
and one inner brush to the contact segments of the commutator, then through one
of the wires connecting the commutator with the accumulator and so through
the group of cells to which the said wire is connected and which is therefore
charged. The current then flows through the next connecting wire to the contact
segment which it connects to the battery, the other inner brush, the rotating ring
and return conductor to the generator.
During this operation the equalizing battery remains unaffected, that is to say,
if its electromotive force or tension corresponds to the tension of the current
supplied by the generator. In general, however, its tension will be higher than
that of the group of accumulators to be charged so that the work of the charging-
current will be assisted by the said equalizing battery.
If the inner brushes be revolved they move out of contact with the contact
segments or plates so that the battery group which was being charged is discon-
nected from the circuit. The charging current from the generator is during
this charge kept flowing by the equalizing battery which is therefore charged in
the ordinary manner. Its tension can therefore be regulated by switching cells
into and out of the circuit by means of a switch in the usual manner.

page_text: By still further rotating the inner brushes they are caused to make contact
with two other contact segments so as to enable the charging current to flow to
another battery group which is thereby charged.
In like manner by rotating the commutator brushes the outside battery groups
are successively connected with the charging-circuit and charged.
When discharging, the battery groups are connected up in a continuous series
so that the tension of the discharging-current is as many times greater than the
tension of the charging-current, as the number of groups employed.
The transformation of a high-tension current into a low-tension current is
effected in a similar manner to that above described for the reverse operation.
The high-tension current flows through conductors to the battery to be charged
which consists of a number of groups of cells connected up in series and which
is continuously charged by the said high-tension current. The ends of the
battery and the connections between the successive groups are connected by con-
ducting wires with the contact segments of a fixed commutator.
The two inner brushes, maintained in constant rotation by a motor, slide upon.
the commutator and the fixed brushes, slide upon the rotating rings which carry
the inner brushes. The fixed brushes are connected to the two conductors of the
main or consumption circuit, between which conductors the equalizing battery
is connected up.
When the inner commutator brushes revolve the battery groups, which are
charged in parallel by the high-tension current, are discharged separately through
the consumption circuit. As in the case where a low-tension current is trans-
formed into a high-tension current the equalizing battery, connected up between
the two conductors of the consumption circuit maintains the said circuit unbroken
when the brushes make contact with the insulating segments and do not connect
any battery group with the consumption-circuit. The tension of the said circuit
can be regulated by connecting or disconnecting storage cells with the circuit by
means of a switch in the ordinary manner.
A current of comparatively low tension such as is obtained from a continuous
current dynamo can be transformed in a similar manner, by using a suitable
number of groups of storage cells, into a current of thousands of volts tension
suitable for conveyance through long distances and which can, on arriving at
its destination, be re-transformed into a low-tension current.
The commutator devices can obviously be varied in construction without in
any way modifying the invention.
If in the case of existing plants the current tension is not directly divisible into
the higher tension required or vice versa the highest possible divisor is found that
will divide into both tensions without a remainder and both the primary and
secondary batteries are divided into a corresponding number of equal groups of
elements or cells. The commutator device must obviously be so arranged that
it connects at equal intervals of time a group of primary and secondary batteries
of equal size. In lieu of this arrangement an intermediate battery which corre-
sponds to the divisor can be introduced into the circuit. This arrangement ex-
cludes the possibility of an earth connection being set up between the primary
and secondary batteries.
Experiment has shewn that by my invention currents can be transformed
between any desired limits practically without sparking at the commutator,
which is not the case with the methods for transforming currents as heretofore
practised. As it is very difficult to transform a current of high tension without
some sparking at the commutator, the breaking of the circuit is, in order to pre-
serve the commutator segments as much as possible, effected by a device or
arrangement wherein those parts which are liable to wear aro easily replaceable.
In this arrangement the current supplied by the dynamo and which is designed
to charge the high-tension battery passes from the equalizing battery through
a spark-catcher to the commutator. This spark-catcher consists of an insulating
disc mounted on the same shaft as the commutator and the motor and revolving

page_text: synchronously with the latter. A number of sector-shaped metal strips, corre-
sponding in number and position to the commutator segments are arranged upon
the disc. The said metal strips are made of a conducting material and are elec-
trically connected to the shaft on which the disc is mounted. A spring makes
contact with the shaft and is connected to one pole of the charging-circuit, the
other pole of which is connected to a second spring in contact with the disc. The
width of the metal strips is so calculated, and the second contact spring is so
arranged, that the current passing through the two contact-springs to the commu-
tator is cut off just before the commutator brushes leave the corresponding seg-
ments. Similarly, the current from the second contact spring will not again flow
until the commutator brushes have come into contact with the next segments. All
the sparks, therefore, that are formed appear between the second contact spring
and the edges of the sector-shaped metal strips which can, when necessary, be
easily removed and replaced.
But in order to still further minimize the evil effects of sparking the disc is
rotated within a vessel filled with distilled water, alcohol or any other suitable
insulating liquid, which extinguishes the sparks. Or the sparks can be mag-
netically or mechanically blown away.,
Instead of an insulating disc a drum or the like can be employed.
Improvements in Transforming Continuous Electric Currents.
We, ADOLPH MÜLLER, of 90, Bergstrasse, Hagen, Westphalia, in the German
Empire, Director, and HENRI TUDOR, of Rosport, in the Grand Duchy of Luxem-
bourg, 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 transforming continuous electric cur-
rents by means of accumulators or secondary batteries.
To transform a continuous current of a given tension to a current of a different
tension by means of accumulators or secondary batteries it has hitherto been cus-
tomary, when it is desired to transform a high-tension current into a low-tension
current, to arrange the elements in series for charging and in parallel for dis-
charging and when it is desired to transform a low-tension current into a high-
tension current to proceed in the opposite manner, that is to say, to arrange the
elements in parallel for charging and in series for discharging. With this arrange-
ment continuous working can only be obtained by employing two separate
batteries of full capacity, the said batteries being alternately charged and dis-
charged so that the process is thus made expensive.
Endeavours have been made to obviate this disadvantage by employing a com-
mutator, which successively connects the groups or series of the single battery
employed with the charging or discharging-circuit. In such arrangements, to
obviate the interruptions of the current attending the operation of the commutator,
the brushes are made of such a width, that they completely cover the insulating
segments when passing over them so that each group of the battery elements
or cells is unavoidably short circuited by the commutator brushes, thereby giving
rise to disturbances which prevent the arrangements answering in practice.

page_text: If the insulating segments are, in order to avoid the short-circuiting of the
whole battery, made of such a width that the brush does not completely cover
them, the circuit is completely broken and the current interrupted so that powerful
sparking takes place at the commutator, which sparking also prevents the efficient
working of the arrangement.
In some cases the complete interruption of the charging current is avoided by
the introduction into the circuit of a shunt which can consist of a resistance coil
or of accumulators. If accumulators be used they must, as in the case of the
single groups which are to be charged, be constantly disconnected and replaced
by others. This would make the complicated connections necessitated by the
disconnection of the single battery groups from the discharging-circuit, still more
complicated, as in order to charge one group of accumulators four groups would
have to be reversed or have their connections altered.
Furthermore, with this arrangement it is only possible to transform a low-tension
current into a high-tension current, the reverse, that is to say, the transformation
of a high-tension current into a low-tension current not being possible.
Now this invention relates generally to means for transforming continuous
currents at any tension into currents at any desired higher or lower tension. The
chief object of the invention is to employ a current, transformed by means of
storage batteries or accumulators, to transmit electrical energy from a current
generator or source of current to a distance by means of conductors of small cross-
section and to render it utilizable at its destination, as also to convert a continuous
current of any given, tension into a continuous current of any other desired tension
to be used in conjunction with the same source of current.
According to the invention the transformation of the current is effected without
any interruption of the currents flowing through the charging and discharging-
circuits and without the possibility of even a momentary short-circuiting through
the commutator brushes taking place. Furthermore, the arrangement enables
the regulation of the current used to be suitably effected without the employment
of any switch devices other than those generally known in connection with accumu-
lators or secondary batteries.
This is effected by introducing between the two conductors or leads of the low-
tension current a second accumulator or secondary battery of the same clectro-
motive force or tension as the said circuit. This battery takes no part in diverting
or reversing the current but has for its object to equalize the difference of potential
arising from the interruptions of the current caused during the change of con-
nections.
In the accompanying drawing,-.
Figure 1 is a diagrammatic view illustrating an arrangement for transforming
a low-tension current into a high-tension current;
Figure 2 is a similar view, of an arrangement for transforming a high-tension
current into a low-tension current;
Figures 3 and 4 are diagrammatic views of a detail hereinafter described; and
Figures 5 and 6 are diagrams illustrating the invention and hereinafter
described.
The source of current or generator G has proceeding from it two conductors
or leads a, a¹ between which. an equalizing accumulator or secondary battery b
is introduced and which pass to the brushes c c¹ of a commutator U, the contact
rings d, d of which are continuously rotated preferably by means of a small
electro-motor M. The rotating rings carry inner brushes e, e¹ in contact with a
fixed commutator K and the contact segments f¹, f³, f³, ft, f³ of the commutator,
which segments are separated by broad or thick insulating segments are con-
nected by conductors h¹, h2, h3, h4, h5 to an accumulator or secondary battery which
consists of a corresponding number (4) of groups or series k³, 12, 13, 14 of cells.
The two extreme conductors h¹ and 5 are connected to the two ends of the battery
and the others to the connections 1, 2, 3 between the separate groups of cells.
By means of the said connections, the groups are arranged in series and
,

page_text: can, therefore, be discharged by the wires or connections 7, 11 secured to the ends
of the battery at a tension which depends upon the number of groups employed.
The current passes from the generator G when the brushes e, el are in the posi-
tion shewn through the conducting wire a, commutator brush c rotating ring d
and brush e to the contact segment f2 of the commutator, then through the wire h
connecting the commutator with the accumulator and so through the group of
cells to which the said wire is connected and which is therefore charged. The
current then flows through the wire h³ to the contact segment f³ the brush e¹, the
rotating ring d¹ and return conductor a¹ to the generator G.
During this operation the equalizing battery 6 remains unaffected, that is to
say, if its electromotive force or tension corresponds to the tension of the current
supplied by the generator G. In general, however, its tension will be higher than
that of the group of accumulators to be charged so that the work of the charging-
current will be assisted by the said battery b.
If the brushes e, e¹ be revolved they move out of contact with the contact seg
ments or plates f³, fa so that the battery group which was being charged is
disconnected from the circuit. The charging current from the generator G is
during this change kept flowing by the battery b which is therefore charged in the
ordinary manner. Its tension can, therefore, be regulated by switching cells
into and out of the circuit by means of the switch s in the usual manner.
By still further rotating the brushes e, e¹ they are caused to make contact with
the contact segments f³, f so as to enable the charging current to flow through
the wires h3, h4 to the battery group 3 which is thereby charged.
In like manner by further rotating the commutator brushes the battery
groups k, k¹ etc. are successively connected with the charging-circuit and charged.
When discharging, the groups of the battery B are connected up in a continuous
series so that the tension of the discharging-current is as many times greater than
the tension of the charging-current, as the number of groups employed.
The transformation of a high-tension current into a low-tension current is
effected in a similar manner to that above described for the reverse operation.
The high-tension current flows through the conductors 1, (Figure 2) to the
battery B to be charged which consists of a number of groups 1, 13, 13, 14 of
cells connected up in series and which is continuously charged by the said high-
tension current. The ends of the battery B' and the connections 1, 12, 13 between
the successive groups are connected by conducting wires h1, h2, h¹³, h14, h15 with
the contact segments fll, F12, F13, f14, fis of a fixed commutator.
Two brushes elo, ell, maintained in constant rotation by a motor M, slide upon
the commutator and the fixed brushes co, cll slide upon the rotating rings do, d
which carry the brushes elo, ell. The fixed brushes clo, cl are connected to the
two conductors a¹0, all of the main or consumption circuit, between which con-
ductors the battery 6' is connected up.
18
When the commutator brushes e¹0, ell revolve, the battery groups, which are
charged in series by the high-tension current, are discharged separately through
the consumption circuit. In the position of the brushes elo, ell shewn, the
group
is connected to the wires a¹0, a" by the conductors h¹8, 13, contact plates fla, ₤13,
brushes elo, ell, rings (10, d¹ and brushes clo, c11. The equalizing battery, b, con-
nected up between the two conductors of the consumption circuit, maintains the
said circuit unbroken when the brushes make contact with the insulating seg-
ments and do not connect any group of the battery B¹ with the consumption-circuit.
The tension of the said circuit can be regulated by connecting or disconnecting
storage cells with or from the circuit by means of a switch s¹ in the ordinary
manner.
A current of comparatively low tension, such as is obtained from a continuous
current dynamo, can be transformed in a similar manner, by using a suitable
number of groups of storage cells in the battery B, into a current of thousands
of volts tension suitable for conveyance through long distances and which can,
on arriving at its destination, be transformed into a low-tension current.

page_text: The commutator devices can obviously be varied in construction without in
any way modifying the invention.
If in the case of existing plants the current tension is not directly divisible
into the higher tension required or vice versa the highest possible divisor is found
that will divide into both tensions without a remainder and both the primary
and secondary batteries are divided into a corresponding number of equal groups
of elements or cells. The commutator device must obviously be so arranged that
it connects at equal intervals of time a group of primary and secondary batteries
of equal size.
If it be required, for example, to transform a continuous electric current from
a tension of 66 volts to a similar current at a tension of 110 volts or vice versa, the
necessary high tension battery of 110 volts is divided into 5, and the low tension
battery of 66 volts into three groups each of 22 volts tension and the poles of the
groups of both batteries are connected to the contacts of a switch device as is
diagrammatically shewn in Figure 5. The poles of the groups I, II, III, IV, V
of the high tension battery B are connected to the contact pieces C1, C2, C3, C4,
C5, C6 and those of the groups 1, 2 and 3 of the low tension battery 6 to the con-
tacts c¹, c², c³, c¹. The switch device is thereby so arranged that when it is
operating, the groups of both batteries are brought into connection one after the
other in order as will be understood from the following table.

page_text: +
of the contacts C³, C³, C³ ... or c¹, c², c³, c. By changing the contacts of the groups
of the low tension battery b with respect to those of the high tension battery B
the intermediate battery z is, as is indicated in the diagram, not brought into con-
tact simultaneously with a group of the high tension battery and one of the low
tension battery, so that direct connection between the two batteries B and bis
avoided and the intermediate battery z is alternately charged with a certain quan-
tity of electricity and discharged to the same extent, in a continuous manner.
By this arrangement, and especially in such cases where, for example, to convey
electrical energy to a distance or for driving street cars, one pole of the high
tension battery is connected to earth, the risk of connecting the high tension
current to earth by the low tension battery b is obviated. In particular the flow
of the high tension current into the low tension consumption circuit when the
intermediate battery z is switched into the circuit in the above described manner
is completely avoided thus doing away with the danger to life and limb from the
high tension current.
Experiment has shewn that by our invention currents can be transformed
between any desired limits practically without sparking at the commutator, which
is not the case with the methods for transforming currents as heretofore practised.
As it is very difficult to transform a current of high tension without some sparking
at the commutator, the breaking of the circuit is, in order to preserve the commu-
tator segments as much as possible, effected by a device or arrangement illustrated
diagrammatically in Figures 3 and 4 wherein those parts which are liable to wear
are easily replaceable.
In this arrangement the current supplied by the dynamo and which is designed
to charge the high-tension battery B passes from the battery through a spark-
catcher to the commutator U. This spark-catcher I consists of an insulating
disc S mounted on the same shaft as the commutator U and the motor M and
revolving synchronously therewith. A number of sector-shaped metal strips T,
corresponding in number and position to the commutator segments are arranged
upon the disc S. The said metal strips T are made of a conducting material and
are electrically connected to the shaft R on which the disc S is mounted. A
spring O¹ makes contact with the shaft and is connected to one pole of the charging-
circuit, the other pole of which is connected to a second spring 02 in contact with
the disc S. The width of the metal strips T is so calculated and the second con-
tact spring 03 is so arranged, that the current passing through the two contact-
springs 0 and 02 to the commutator is cut off just before the commutator brushes
leave the corresponding segments. Similarly, the current from the spring 0³
will not again flow until the commutator brushes have come into contact with
the next segments. All the sparks, therefore, that are formed appear between the
spring 0 and the edges of the sector-shaped metal strips T which can, when
necessary, be easily removed and replaced.
But in order to still further minimize the evil effects of sparking the disc S is
rotated within a vessel F filled with distilled water, alcohol or any other suitable
insulating liquid, which extinguishes the sparks. Or the sparks can be mag-
netically or mechanically blown away.
Instead of an insulating disc a drum or the like can be employed.
Having now particularly described and ascertained the nature of our said in-
vention and in what manner the same is to be performed, we declare that what
we claim is;-
1. In transforming continuous electric currents by means of a commutator
device which successively connects up the groups of a high tension accumulator
or secondary battery in a low tension circuit, the arrangement whereby an accumu-
lator or secondary battery is connected up in parallel with the current generator
or with the current consumers of the low tension circuit for the purpose of pre-
venting variations or fluctuations in tension and the breaking of the low tension
circuit, substantially as hereinbefore described.

page_text: 2. An arrangement of the kind described in Claim 1 wherein the accumulator
or secondary battery, connected up in parallel to the current generators or the
current consumers of the low tension circuit, is divided into groups, the poles of
which are successively connected to those of the groups of the high tension battery
for the purpose of enabling any desired relation between the tensions of the
high tension and low tension circuits to be obtained, substantially as hereinbefore
described.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.