A. Rotary Converter or Transformer for Simple or Polyphase alternating Electric Currents.
Year: 1899

page_text: Date of Application, 8th Apr., 1899
Complete Specification Left, 21st Dec., 1899-Accepted, 27th Jan., 1900
PROVISIONAL SPECIFICATION.
A. Rotary Converter or Transformer for Simple or Polyphase
alternating Electric Currents.
I, JOHN IMRAY, of Birkbeck Bank Chambers, Southampton Buildings, in the County
of London, Consulting Engineer and Chartered Patent Agent, do bereby declare the
nature of this invention (as communicated to me from abroad by La Société Anonyme
pour la Transmission de la force par L'Electricité, of 13, Rue Lafayette, Paris, France,
Manufacturers,) to be as follows:-
Fig. 1 of the accompanying drawings is a side view of a transformer according to
this invention. It consists of two Gramme rings A A and B B on the same shaft 00
and a commutator CC on which bear brushes F to collect the resulting continuous
current.
The ring A A revolves within an inductor D D of an asynchronous machine for
simple alternating currents. The end view Fig. 2 shews how the coil of this
inductor is arranged, and how the sheets which form the rings A A and D) D are cut.
The ring BB, consisting of the same sheets as A A, revolves within an inductor for
a continuous current machine of which the field coils, as shewn in Fig. 3, are
connected in shunt to the brushes F. It is generally of advantage to give bobbins
compound winding, adding to the shunt circuit of the brushes a circuit connected in
series to the external circuit in which a continuous current is required. A series of
copper bolts a pass through the polar extensions E E of the inductor very near the air
space, and have their ends connected by two conducting rings G one on each side of
the inductor. The successive sections of the rings AA and B B are connected to
each other and to the commutator segments C C according to a special arrangement,
about to be described with reference to Fig. 4. The two rings have the same
number of sections, if looked at in a plane passing through the axis of the system,
each section of the ring B B is connected parallel to the section of A A situated
symmetrically with it relatively to the said plane. There are thus formed as many
distinct circuits as there are sections of the ring B B.
These circuits are connected to each other and to the commutator segments C C in
the usual way, that is to say, as for the ring of a continuous current machine, with
the sections only of the ring B B. As shewn in Fig. 4 the line X Y represents the
line of the plane of symmetry considered on a plane normal to the axis of the system.
The projections, on the plane normal to the axis, of the sections of the ring BB are
represented by the rectangles cross hatched, those of the sections of A A by the
rectangles & simply hatched. In order to avoid confusing these, the two rings are
supposed to turn relatively apart. The commutator segments being shewn at K, it
can be seen how the connections above described may be made without any crossing
of the wires. These connections can therefore be made as easily as those of ordinary
continuous current machines.

page_text: the current tends, as is known, to develop two constant fields f¹ and f2 which revolve
round the axis with velocity z, the field f¹ turning in the direction of the arrow and
the other in the opposite direction. Thus the field 1 has a speed relatively to the
ring A A and ƒ² bas a speed
3z
1 2
relatively to the same ring. The field f¹ develops
2.
!
electromotive forces of frequency presenting successive differences of phase in the
different sections of the ring A A and consequently in those of the ring B B which
are connected to them.
2
At every instant, there is a constant difference of potential developed between the
sections of the ging. A. A situated at the extremities of a diameter xy (Fig. 2), this
turning round the axis O with velocity" and consequently with velocity relatively
2
to the ring A A. Likewise on the ring B B the sections between which the constant
difference of potential is developed are situated at the extremities of a diameter x¹ y¹
revolving with velocity relatively to the ring B B. But each section of the one
ring being connected to that of the other ring which is symmetrical to it relatively
to a plane passing through the axis of the system and moving with it, the two
diametersy and a y¹ are always symmetrical relatively to this plane, that is to say
their projections on a plane normal to the axis at every instant make equal angles u
of contrary sign with the projection XY of the symmetrical plane, (see Fig. 5).
2
The diameter x y turning in the same direction as XY with the relative velocity
the diametery turns in the opposite direction with the same relative velocity.
But as XY moves with the rings at an absolute velocity of 2/2, the diameter æ¹ y¹
remains stationary. It follows that there is always constant difference of potential
between the two diametrically opposite segments of the commutator; if herefore the
brushes F F are connected to an external circuit it will be traversed by a continuous
current.
The field tends to develope an alternating electromotive force of frequency 2z
between the two opposite segments, of the commutator. But the ring B B revolves
in the midst of a magnetic screen as previously stated; it cannot therefore be the
seat of a flux variable in space and consequently its sections cannot oppose any
appreciable counter electromotive force to the electromotive forces having frequency 3/25
which the flux f2 would develope in the sections of the ring A A. Matters go on as
if these sections were short circuited for the variations of the flux f2 forming a screen
for it so that it is not developed.
The flux f could be lessened by causing it to pass great air spaces, but as the
'screen of the inductor II is required for other reasons, this is useless and would have
the effect of rendering the developement of the flux fl more difficult.
It has been assumed above that the rings have a velocity z/2 which is immediately.
obtained owing to the presence of the inductor I I. In fact the system acts. thus as a
synchronous motor, and this inductor may be required to furnish at the same time the
unwatted currents necessary to produce the field f¹. The object of the magnetic
screen of the inductor II is to ensure stability of the synchronism.
The apparatus might be started with a continuous current if an accumulator.
battery is accessible. It might also be started as a synchronous motor, but for
that there would be required an auxiliary circuit for the inductor D D of Fig. 2, as is
generally done for asynchronous motors with simple alternating currents.
D

page_text: Finally, for the inductor of the asynchronous machine for simple alternating
current which acts on the ring A A, might be substituted an inductor of an
Asynchronous machine for polyphase currents, thus producing a correcting transformer
for polyphase currents.
PRINCIPAL ADVANTAGES OF THE SYSTEM.
If the inductor of the asynchronous motor which acts on the ring A A is arranged
for high tension currents, this inductor may be considered the primary circuit of a
transformer, and the system is then complete, serving to transforin both the tension
and the nature of the currents.
It is to be observed that the continuous current inductor allows the economical
developement of very intense unwatted currents consequently, in constructing the
alternating current inductor, may be safely adopted windings which can be easily
insulated without risk of magnetic leaks.
On the other band, the commutator has to correct currents of frequency 2/2, then
with any other system, it would have to correct currents of z frequency. This is a
very great advantage, for with equality of tangential velocity of the commutator and
with width of segments the sectioning of the rings may be doubled, and this would
greatly facilitate the commutation and allow of easily producing continuous currents
of high tension.
If the inductor of the asynchronous motor which acts on the ring A A is arranged
for high tension currents, this inductor may be considered the primary circuit of a
transformer, and the system is then complete, serving to transforin both the tension
and the nature of the currents.
It is to be observed that the continuous current inductor allows the economical
developement of very intense unwatted currents consequently, in constructing the
alternating current inductor, may be safely adopted windings which can be easily
insulated without risk of magnetic leaks.
On the other band, the commutator has to correct currents of frequency 2/2, then
with any other system, it would have to correct currents of z frequency. This is a
very great advantage, for with equality of tangential velocity of the commutator and
with width of segments the sectioning of the rings may be doubled, and this would
greatly facilitate the commutation and allow of easily producing continuous currents
of high tension.
ABEL & IMRAY,
Agents for the Applicant..
A Rotary Converter or Transformer for Simple or Polyphase
alternating Electric Currents.
I, JOHN IMRAY, of Birkbeck Bank Chambers, Southampton Buildings, in the
County of London, Consulting Engineer and Chartered Patent Agent, do hereby
declare the nature of this invention (as communicated to me from abroad by La
Société Anonyme pour la Transmission de la force par L'Electricité, of 13, Rue
Lafayette, Paris, France, Manufacturers,) and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following state-
ment:
My invention relates to a rotary converter or transformer for simple or polyphase
alternating currents, as I shall describe referring to the drawings accompanying my
Provisional Specification.
Fig. 1 is a side view of a transformer according to this invention. It consists of
two Gramme rings A A and B B on the same shaft 00 and a commutator C C on
which bear brushes F to collect the continuous current which results from the
operation of the machine.
The ring A A revolves within an inductor DD of an asynchronous machine for simple
alternating currents. The end view Fig. 2 shews how the coil of this inductor is
arranged, and how the sheets which form the rings A A and D D are cut.
The ring B B, consisting of the same sheets as A A, revolves within an inductor
for a continuous current machine of which the field coils, as shewn in Fig. 3, are
connected in shunt to the brushes F. It is generally of advantage to give the
bobbins compound winding, adding to the shunt circuit of the brushes a circuit con-
nected in series to the external circuit in which a continuous current is required. A
number of copper bolts a pass through the polar extensions E E of the inductor
very near the air space and have their ends connected by two conducting rings G,

page_text: one on each side of the inductor. The successive sections of the rings A A and B B
are connected to each other and to the commutator segments C C according to a
special arrangement, about to be described with reference to Fig. 4. The two ring
have the same number of sections, if looked at in a plane passing through the axis of
the system, each section of the ring B B is connected parallel to the section of A A
situated symmetrically with it relatively to the said plane. There are thus formed
as many distinct circuits as there are sections of the ring B B.
These circuits are connected to each other and to the commutator segments CO
in the usual way, that is to say, as for the ring of a continuous current machine,
with the sections only of the ring B B. As shewn in Fig. 4, the line XY, represents
the line of the plane of symmetry projected on a plane normal to the axis of the
system. The projections, on this plane, of the sections of the ring B B are repre-
sented by the cross hatched rectangles those of the sections of A A by the simply
hatched rectangles s. In order to avoid confusing these, the two rings are supposed
to turn relatively apart. The commutator segments being shewn at K, it can be
seen how the connections above described may be made without any crossing of the
wires. These connections can therefore be made as easily as those of ordinary con-
tinuous current machines.
(Figs. 1 and 2), and the shaft is turned with velocity 5 in the direction of the arrow 3,
2
the current tends, as is known, to develope two constant fields f and f which revolve
round the axis O with velocity 2, the field ¹ turning in the direction of the arrow
and the other in the opposite direction. Thus the field ƒ¹ has a speed relatively to
3z
2.
the ring A A and f² has a speed relatively to the same ring.. The field si
developes electromotive forces of frequency presenting successive differences of
phase in the different sections of the ring A A and consequently in those of the
ring B B which are connected to them.
At every instant there is a constant difference of potential developed between the section
of the ring A A situated at the extremities of a diameter & y (Fig. 2), this turning round
the axis with velocity and consequently with velocity relatively to the ring A.A.
Likewise on the ring B B the sections between which the constant difference of
potential is developed are situated at the extremities of a diameter y revolving
with velocity relatively to the ring B B. But each section of the one ring being
connected to that of the other ring which is symmetrical to it relatively to a plane
passing through the axis of the system and moving with it, the two diameters ry
and xy are always symmetrical relatively to this plane, that is to say their pro-
jections on a plane normal to the axis at every instant make equal angles of
contrary sign with the projection XY of the symmetrical plane, as indicated in
Fig. 5.
The diameter x y turns in the same direction as XY with the relative
the diameter ¹y turns in the opposite direction with the same relative
velocity
velocity.
But
2
2,
as XY moves with the rings at an absolute velocity of the diameter x¹ y¹
emains stationary. It follows that there is always constant difference of potential
etween the two diametrically opposite segments of the commutator; if therefore, the

page_text: If the inductor of the asynchronous motor which acts on the ring A A is arranged
for high tension currents, this inductor may be considered the primary circuit of a
transformer, and the system is then complete, serving to transform both the tension
and the nature of the currents.
It is to be observed that the continuous current inductor allows the economical
developement of very intense unwatted currents, consequently in constructing the
alternating current inductor windings which can be easily insulated without risk of
magnetic leaks may be safely adopted.
On the other hand, the commutator has to correct currents of frequency then
with any other system, it would have to correct currents of Z frequency. This is a
very great advantage, for with equality of tangential velocity of the commutator and
with width of segments the sectioning of the rings may be doubled, and this would
greatly facilitate the commutation and allow of easily producing continuous currents
of high tension.
The apparatus described, once started, revolves with a speed half that which a
synchronous motor of the same polarity would have, so that a continuous current
can be collected by the brushes of the continuous current motor.
It receives energy
from the simple or polyphase currents which pass the field coils that act as the
primaries of this transformer. The machine is reversible and can transform a con-
tinuous current of constant voltage into a simple or polyphase alternating current of
constant effective voltage.

page_text: Having thus particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, 1 declare that what I claim
A rotary transformner or converter for simple or polyphase alternating electric
currents having combined on an axis an asynchronous motor and a continuous
current motor, the asynchronous armature coils being grouped as those of the
continuous current armature, and also connected in shunt to the plates of the con-
tinuous current commutator, but each group of the asynchronous armature coils
being connected not to the group of the continuous motor coils situated in, the same
axial plane, but to the group symmetric with it relatively to a fixed plane.
Dated this 21st day of December 1899.
ABEL & IMRAY,
Agents for the Applicant.