Improvements in Dynamo Electric Machines.
Year: 1893

page_text: Date of Application, 24th June, 1893
Complete Specification Left, 15th Feb., 1894-Accepted, 7th Apr., 1894
PROVISIONAL SPECIFICATION.
Improvements in Dynamo Electric Machines.
We, MAURICE HUTIN, of No. 46 Rue Caumartin, Paris, Engineer, and
MAURICE LEBLANC of No. 63 Allee du Jardin Anglais, Le Raincy, Seine and Oise,
France, Engineer, do hereby declare the nature of this invention to be as
follows:-
The difficulties met with in applying alternating electric currents are due, as is
well known, to the phenonema of self induction, which correspond with those of
inertia observed when a material fluid, such as air or water is substituted for
electricity. In dynamo electric machines these phenonema are of preponderating
importance, resulting practically in a great loss of efficiency, so much so that it is
universally recognised that to obtain with alternating currents results equivalent to
those obtained with continuous currents involves much greater expense.
66
We have shewn how the effects of self induction in alternating current machines
can be suppressed by combining suitable condensers with them. This arrangement,
quite practicable in dealing with currents of great frequency, is not so under
present working conditions in dealing with currents of ordinary frequency, for the
cost of the condensers becomes too great relatively to the useful effect of the
machine. It is therefore necessary to find some other way of destroying the effects
of self induction in machines having currents alternating with moderate or little
frequency. Theory shews that there can be only two ways of overcoming self
induction, first, by combination of condensers as above mentioned, secondly, by
subdividing the armature into a large number of elementary circuits the grouping
of which is modified every instant by the action of a special organ called a
collector," the invention of which organ has been the means of bringing continuous
current machines to their present perfection. This apparatus allows at every
instant the grouping of the various coils of an armature into circuits comprising a
number of coils having the electro motive forces of self induction in the one
direction with a like number of coils having them in the opposite direction.
this manner the different parts of the armature only exchange among themselves
their potential energies, whereas, when condensers are used, there is an exchange
of energy between each circuit of the armature and the condenser adjoined to it.
When the frequency of alternation is low or moderate, the cost of a collector is
much less than that of a condenser which can give equal results. It is therefore
of the highest importance to be able to furnish alternating current machines with
collectors obviating the effects of their self induction. This is the object of our
present invention.
PRINCIPLE OF THE SOLUTION.
In
Let us consider any continuous current machine having its armature divided
into 2 n sections, the collector having 2 n segments. The current which traverses
each section changes its direction every time that the two collector segments
between which the section is comprised, pass under the brushes. The variations of
intensity in the section may be represented by the line at a', Figure 1; it remains
constant in absolute value and undergoes periodic reversals, the frequency of
which is equal to the speed of rotation of the machine expressed in revolutions
per second, if the machine is bipolar. The intensity is the same in the other
L
1
T
1 1:s of whose caval

page_text: ton of period in passing from one section to the next, as indicated at a² & a
Figure 1. Further, the electro motive forces developed by the rotation of the
machine in all its sections are periodic, of frequency, presenting a difference of
phase equal ton of period in passing from one section to the next.
All that is said above is independent of the loading of the dynamo brushes, that
is to say of the algebraic sum at any instant of the electromotive forces connected
in series between the two brushes. The action of the collector in suppressing the
effects of self induction is independent of this loading.
1
T
Let us now suppose that the circuit of each section is prolonged beyond the
machine to comprise an external circuit as shewn in Figure 2 where the armature
sections S and the segments t of the collector T are each 12 in number. Each
section S is connected in series with a distinct external circuit V, and these
duplex sections consisting of S and V are connected together and to the segments
of the collector in the usual way. The exterior circuits V are traversed by the
same currents as the circuits S, having the same periodic reversals and successive
differences of phase of n in this case. Should the exterior circuits present new
electromotive forces which the currents traversing these circuits would have to
overcome, if these forces were also periodic, equal as to amplitude, of equal
frequency and presented successive differences of phasen, in passing from one
circuit to the next, the introduction of these electro motive forces would be simply
equivalent to changing the load on the brushes. A continuous current would always
be collected between the brushes and the apparent self induction of the system
would be nil, the same indeed as we have explained for the ordinary working of a
continuous current machine; the resulting circuit will always contain as many
currents having the electromotive forces of self induction in the one direction as
there are circuits having them in the opposite direction. We can thus conceive a
machine the self induction of which is nil, and which develops in 2n distinct
circuits external to itself as many periodic currents of phase n of a period different.
It could at the same time furnish a continuous current between its brushes. If it is
to be used only as an alternating current motor the brushes are connected in short
circuit. In order to use such a machine directly, 2n conductors would be required
made to work equally, which would not be practicable. But it is now recognised
that it is advantageous to employ only alternating machines giving currents of low
tension and to transform these into currents of high tension by transformers.
In our former studies for solving the problem of converting poly phase alter-
nating currents into continuous currents, we devised a transformer specially
arranged to transform 3 currents differing in phase by of a period or 4 currents
differing by, led by as many separate conductors into 2n periodic currents
differing successively in phase by n of a period developed in 2n distinct circuits,
the variations of which in terms of the time are represented by Fig. 1 in our
Specification No. 17826 of 1892.
This apparatus is reversible. Consequently if for the 2n exterior circuits of
Fig. 2 we substitute the 2n secondary circuits of the transformer, we can obtain
in the primary conductors two or three currents differing in phase as may be
arranged.
This transformer like apparatus of the kind, has no apparent self induction and
therefore cannot introduce it in the system. Moreover, the 2n circuits thus con-
nected to the machine serve, by virtue of the transformer's action, as the seat of
contrary electiomotive forces fulfilling the conditions above defined, that is to say,
periodic, of frequency, and differing in phase by n of a period. The action of
the generator will therefore not be modified, and we can in fact obtain
3 or 4 currents differing in phase by or of a period capable of being
distributed and utilised by 3 or 4 conductors in the usual way. Thus the problem
is solved in the case of polyphase currents.

page_text: EXAMPLES OF APPLICATION.
Figs. 3, 4, 5 and 6 relate to a multipolar machine specially constructed for
acting as above described. Fig. 3 is a half section through the axis. The induced
armature G is a stationary Gramme ring. Within it revolves a single inductor I
excited by a single coil K concentric with the axis. Its boss is made with polar
extensions L, half of which proceed from each end. These extensions cross each
other under the Grammne ring G and constitute a series of poles alternatively
positive and negative, as shown in Fig. 3 and in Fig. 4 which shew part of a section
transverse to the axis. The polar extensions are pierced with holes in which are
inserted copper bolts parallel to the axis, the ends of these bolts being rivetted
in two brass circles. The object of this arrangement is to constitute a series of
deadening circuits intended to facilitate and maintain the synchronising of the
dynamos whether several generators are employed in parallel or when power is
communicated. The action of this apparatus is explained in our Specification
No. 13765 of 1892.
In practice, machines of this kind would usually be multipolar, in order to
obtain sufficient frequency without requiring excessive speed of rotation. The
arrangement of such machine may be readily understood, as a multipolar
machine may be considered a group of distinct machines combined in one, each
elementary machine comprising the sections comprised between two successive
poles of the same name. The sections of each machine, occupying the same
position relatively to the poles, produce at the same time the same electromotive
forces. These sections may be connected in series or in quantity, and thus there
may be constituted with the whole machine as many groups of sections as there
are sections in an elementary machine, each of these groups then acting as a
section of the bipolar machine above described and being grouped along with the
others with the segments of a collector and the elementary circuits of the
transformer as shewn in Fig. 2.
The collector being stationary, the brushes must move.
In order that they may
turn with the same speed as the dynamo, the collector should be made to have as
many segments as there are sections altogether in the machine, by connecting in
quantity all the segments corresponding to the sections connected together. We
have shewn in Fig. 5 a system of collector and brushes which we prefer. The
collector M is hollow and has revolving within it a kind of star N, of brass,
hollow, with its interior surfaces covered with insulating material. In the rays of
this star are arranged carbon pencils O which constitute the brushes, and which
are caused by centrifugal force to bear against the surface of the collector. These
carbons are galvanised, and each has soldered to it a flexible wire f to convey away
the current. Fig. 6 is an end view of one of the brushes having a number of the
carbons placed in one ray of the star.
When the machine is to act merely as a generator, its inductor being supplied
from a special source, all the brushes may be connected together and the surfaces
of the star need not be insulated. When the machine is to act as a motor, its
inductor may he excited by the current furnished from the brushes, this current
being continucus when the machine is synchronised. Fig. 7 is a general view of
the described machine.

page_text: consequently the machine could only work at the speed of synchronism and could
not start itself.
The flux must not therefore be deadened in all directions. On the other hand,
the system of inductor which we employ, and which presents great advantages
in respect of small expenditure in energy of excitation, has not the division of its
magnetic cores. We therefore advise for motors the use of an inductor such as is
shewn in Fig. 8. It consists of a pile of metal sheets cut to star shape insulated
and superposed. The rays of the star expand towards the circumference, all being
wound with coils as indicated by the curved arrow on one of them. The connections
are so made that the same current determines at the ends of the rays a series of
poles alternately positive and negative.
The expanded ends are traversed by deadening bolts insulated from the metal
sheets and having their ends rivetted in two brass circles which serve also to keep
the metal sheets close together. Thus the deadeners oppose the production of any
flux closing on itself around the bolts as indicated by the curve a By 8, but
they do not oppose the inductor fluxes properly so called, which close upon
themselves as indicated by A B C. Under these conditions the machine can
start.
APPLICATION OF THE SYSTEM IN THE CASE OF MONOPHASE CURRENTS.
This application is immediate, the only modification required in the system
above described for polyphase currents being to send the single current which is
available into only one of the primary circuits of the transformer, short circuiting
the others. The energy stored in the circuits closed on themselves in virtue of
their self induction operates as a flywheel, which provides against the variations
of energy transmitted by the line. Under these conditions, the transformers
are capable of transforming any alternating current into 2n alternating currents
of the same frequency but successively differing in phase by n of period, and
conversely.
Dated this 24th day of June 1893.
ABEL & IMKAI,
Agents for the Applicants.
"
COMPLETE SPECIFICATION.
Improvements in Dynamo Electric Machines.
We, MAURICE HUTIN of No. 46 Rue Caumartin, Paris, Engineer, and
MAURICE LEBLANC of No. 63 Allee du Jardin Anglais, Le Rancy, Seine and
Oise, France, 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 :-
The difficulties met with in applying alternating electric currents are due, as is
well known, to the phenomena of self induction, which correspond with those of
inertia observed when a material fluid, such as air or water is substituted for
electricity. In dynamo electric machines these phenomena are of preponderating
importance, resulting practically in a great loss of efficiency, so much so that it is
universally recognized that to obtain with alternating currents results equivalent
to those obtained with continuous currents involves much greater expense.
We have shewn how the effects of self induction in alternating current machines
can be suppressed by combining suitable condensers with them. This arrangement,
quite practicable in dealing with currents of great frequency, is not so under
present working conditions in dealing with currents of ordinary frequency for the
cost of the condensers becomes too great relatively to the useful effect of the

page_text: T
Let us consider any continuous current machine having its armature divided
into 2 n sections, the collector having 2 n segments. The current which traverses
each section changes its direction every time that the two collector segments
between which the section is comprised, pass under the brushes. The variations of
intensity in the section may be represented by the line at a', Fig. 1; it remains
constant in absolute value and undergoes periodic reversals the frequency of which
is equal to the speed of rotation of the machine expressed in revolutions per
second, if the machine is bipolar. The intensity is the same in the other sections
of the armature with similar reversals but with difference of phase equal to n
of period in passing from one section to the next, as indicated at a to a, Fig. 1.
Further, the electromotive forces developed by the rotation of the machine
in all its sections are periodic, of frequency, presenting a difference of phase equal
ton of period in passing from one section to the next.
All that is said above is independent of the loading of the dynamo brushes, that
is to say of the algebraic sum at any instant of the electromotive forces connected
in series between the two brushes. The action of the collector in suppressing the
effects of self induction s independent of this loading.
Let us now suppose that the circuit of each section is prolonged beyond the
machine to comprise an external circuit as shewn in Fig. 2 where the armature
sections S and the segments t of the collector T are each 12 in number. Each

page_text: section S is connected in series with a distinct external circuit V, and these duplex
sections consisting of S and V are connected together and to the segments of the
collector in the usual way. The exterior circuits are traversed by the same
currents as the circuits S, having the same periodic reversals and successive
differences of phasen in this case. Should the exterior circuits present new
electromotive forces which the currents traversing these circuits would have to
overcome, these forces were also periodic, equal as to amplitude, of equal
frequency and presented successive differences of phasen in passing from
1
T
one circuit to the next, the introduction of these electromotive forces would be
A continuous current
simply equivalent to changing the load on the brushes.
would always be collected between the brushes and the apparent self induction of
the system would be nil, the same indeed as we have explained for the ordinary
working of a continuous current machine, the resulting circuit will always contain
as many circuits having the electromotive forces of self induction in the one
We can thus
direction as there are circuits having them in the opposite direction.
conceive a machine the self induction of which is rul, and which develops in 2 n
distinct circuits external to itself as many periodic currents of phase of a period
different. It could at the same time furnish a continuous current between its
brushes. If it is to be used only as an alternating current motor the brushes are
connected in short circuit. In order to use such a machine directly, 2 n conductors
of distribution would be required made to work equally, which would not be
practical. But it is now recognised that it is advantageous to employ only
alternating machines giving currents of low tension and to transform these into
currents of high tension by transformers.
In our former studies for solving the problem of converting polyphase alternating
currents into continuous currents, we devised a transformer specially arranged to
transformi 3 currents differing in phase by of a period or 4 currents differing
by, led by as many separate conductors into 2 n periodic currents differing succes-
sively in phase by n of a period developed in 2'n distinct circuits the variations
of which in terins of the time are represented by Fig. 1 in our Specification
No. 17826 of 1892. This apparatus is reversible. Consequently if for the
2n exterior circuits of Fig. 2, we substitute the 2 n secondary circuits of this
transformer, we can obtain in the primary conductor two or three currents differing
in phase as may be arranged. This transformer, like apparatus of the kind, has no
apparent self induction and therefore cannot introduce it in the system. Moreover,
the 2 n circuits thus connected to the machine serve, by virtue of the transformers'
action, as the seat of contrary electromotive forces fulfilling the conditions above
defined, that is to say, periodic, of frequency and differing in phase by n of a
period. The action of the generator will therefore not be modified, and we can in
fact obtain 3 or 4 currents differing in phase by or of a period capable of being
distributed and utilised by 3 or 4 conductors in the usual way.
Thus the problem
is solved in the case of polyphase currents.
1
EXAMPLE OF APPLICATION.
Figs. 3, 4, 5 and 6 relate to a multipolar machine specially constructed for
acting as above described. Fig. 3 is a half section through the axis. The induced
armature G is a stationary Gramme ring. Within it revolves a single inductor I
excited by a single coil K concentric with the axis. Its boss is made with polar
extensions L, half of which proceed from each end. These extensions cross each
other under the Gramme ring G and constitute a series of poles alternatively
positive and negative, as shewn in Fig. 3 and in Fig. 4 which shews part of a section
transverse to the axis. The polar extensions are pierced with holes in which are
inserted copper bolts & parallel to the axis, the ends of these bolts being rivetted in

page_text: two brass circles. The object of this arrangement is to constitute a series of
deadening circuits intended to facilitate and maintain the synchronising of the
dynamos whether several generators are employed in parallel or when power is
communicated. The action of this apparatus is explained in our Specification
No. 13765 of 1892.
In practice, machines of this kind would usually be multipolar, in order to obtain
sufficient frequency without requiring excessive speed of rotation. The arrange-
ment of such machines may be readily understood, as a multipolar machine may be
considered a group of distinct machines combined in one, each elementary machine
comprising the sections comprised between two successive poles of the same name.
The sections of each machine, occupying the same position relatively to the poles
produce at the same time the same electromotive forces. These sections may be
connected in series or in quantity, and thus there may be constituted with the whole
machine as many groups of sections as there are sections in an elementary machine,
each of these groups then acting as a section of the bipolar machine above
described and being grouped along with the others with the segments of a collector
and the elementary circuits of the transformer as shewn in Fig. 2.
The collector being stationary, the brushes must move. In order that they may
turn with the same speed as the dynamo, the collector should be made to have as
many segments as there are sections altogether in the machine, by connecting in.
quantity all the segments corresponding to the sections connected together.
We
have shewn in Fig. 5 a system of collector and brushes which we prefer. The
collector M is hollow and has revolving within it a kind of star N of brass,.
hollow with its interior surfaces covered with insulating material. In the rays of
this star are arranged carbon pencils O which constitute the brushes, and which
are caused by centrifugal force to bear against the surface of the collector. These
carbons are galvanised, and each has soldered to it a flexible wire to convey
away the current. Fig. 6 is an end view of one of the brushes having a number of
the carbons O placed in one ray of the star.
When the machine is to act merely as a generator, its inductor being supplied
from a special source, all the brushes may be all connected together and the
surfaces of the star need not be insulated. When the machine is to act as a motor,
its inductor may be excited by the current furnished from the brushes, this current
being continuous when the machine is synchronised. Fig. 7 is a general view of
the described machine.
NOTE AS TO THE USE OF THESE MACHINES AS MOTORS.
Machines can operate as motors on condition that they normally revolve with the
speed of synchronism. The absence of self induction and the presence of the
deadeners gives them an absolute stability of movement, but we must then consider
seriously the period of starting. The deadener as shewn in the figures would
oppose the passage of any variable flux in the inductors, consequently the machine
could only work at the speed of synchronism and could not start itself. The flux
must not therefore be deadened in all directions. On the other hand, the system
of inductor which we employ and which presents great advantages in respect of
small expenditure in energy of excitation, has not the division of its magnetic
cores. We therefore advise for motors the use of an inductor such as is shewn in
Fig. 8. It consists of a pile of metal sheets cut to star shape insulated and
superposed. The rays of the star expand towards the circumference, all being
wound with coils as indicated by the curved arrow on one of them. The con-
nections are so made that the same current determines at the ends of the rays a
series of poles alternately positive and negative. The expanded ends are traversed
by deadening bolts insulated from the metal sheets and having their ends rivetted
in two brass circles which serve also to keep the metal sheets close together. Thus
the deadeners oppose the production of any flux closing on itself around the bolts
as indicated by the curve a By, but they do not oppose the inductor fluxes
γ

page_text: properly so-called, which close upon themselves as indicated by A B C.
these conditions the machine can start.
Under
APPLICATION OF THE SYSTEM IN THE CASE OF MONOPHASE CURRENTS.
This application is immediate, the only modification required in the system above
described for polyphase currents being to send the single current which is available
into only one of the primary circuits of the transformer, short circuiting the
others. The energy stored in the circuits closed on themselves in virtue of their
self induction operates as a fly wheel which provides against the variations of
energy transmitted by the line. Under these conditions the transformers are
capable of transforming any alternating current into 2 n alternating currents of the
same frequency but successively differing in phase by n of period, and conversely.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. In order to avoid the effects of self induction in a generator, the use of a
continuous current machine with its collector so arranged that in each section of
the armature there is introduced an exterior circuit in which is to be consumed the
whole or part of the energy rendered disposable in that section, the brushes applied
to the conductor being closed on any circuit.
2. The combination of a like machine with a transformer analogous to those
which we have devised as a transformer of frequency and tension. The transformer
combined with the machine should be capable of utilising the energy furnished by
as many currents of the same frequency but of as many distinct phases as there are
different sections in the armature of the machine. All this energy will be
communicated, as the case may be to 1, 2, 3 &c. currents of the same intensity and
frequency, but regularly varied in phase.
3. The reversibility of the system above referred to and its application to the
production of work at the expense of the energy furnished by one alternating
current, two diphased, or three triphased currents.
Dated this 15th day of Fahruary 1804
ABEL & IMRAY,
Agents for the Applicants.