Improvements in and relating to Dynamo-electric Machines and Electric Motors.
Year: 1889

page_text: Date of Application, 4th June, 1839
Complete Specification Left, 2nd Apr., 1890-Accepted, 3rd May, 1890
PROVISIONAL SPECIFICATION.
[Communicated from abroad by CHARLES S. BRADLEY, of Yonkers, in the County of
Westchester and, State of New York, United States of America, Electrical
Engineer.]
Improvements in and relating to Dynamo-electric Machines and
Electric Motors.
I, HENRY HARRIS LAKE, of the firm of Haseltine Lake & Co., Patent Agents,
Southampton Buildings, in the County of Middlesex do hereby declare the nature
of this invention to be as follows:-
In electric motors generally it has hitherto been considered essential to successful
operation, either to have the field-magnet positively energized by means of a current
or currents circulating in insulated conductors wound upon the field-magnets, or else
to have the field-magnets made of steel and permanently magnetized. It has been
generally considered advisable to laminate the pole pieces of the field-magnets for the
purpose of preventing the generation of Foucault currents therein. The communi-
cator has discovered, on the contrary, that such currents may serve a useful purpose
on the motor or machine and they may be so concentrated and directed as to form the
sole energizing current of the field-magnets.
The present invention in part, consists in an electric motor or dynamo electric
machine of any class to which the invention is applicable, having its field-magnets
energized by currents induced in the mass of the magnet itself as distinguished from
the magnetism produced in the field-magnet by a current or currents circulating in
insulated conductors wound upon the magnet.
The invention further consists in the construction and arrangement of parts for
the above ends and the combination of devices used in starting and operating the
motor.
In the construction of the field magnet I may surround the armature simply with a
cylindrical mass of iron, either cast iron or wrought, and the effect, which I have
already discovered can be produced, will take place in such a plain cylindrical
magnet; but, for the sake of efficiency, I prefer the following construction:-I first
form a skeleton spool or cylinder, composed of longitudinal bars and head, leaving
around the periphery a number of equi-distant slots or openings which are filled with
iron bars so as to present a finsh cylindrical surface on the interior, and a similar
surface on the exterior, thus leaving a space on the outside of the entire structure,
which I then proceed to wind with plain naked iron wire of any suitable size and
shape, or I may wind it with hoop iron or it may be constructed of thin discs of iron
stamped out and slipped onto the spool. By this construction I obtain a cylinder
consisting largely of iron and having copper, or high-conductivity-bronze, beads and
ribs extending internally between the bars of iron which may be considered as
constituting the pole pieces.
The armature may be of various types, but I prefer that having a closed circuit as
in the ring type, having at four equi-distant points connections, each leading to one
of four contact rings placed on the shaft. Current is led into the armature by means
of brushes, opposite brushes being connected to the two supply circuits. These
circuits supply alternating currents, the current of one being one quarter of a phase
or wave-length behind the other, and the result is to produce a rotation of the
armature so long as the currents are supplied and are substantially one quarter phase
apart in their time periods; and in producing the rotation of the armature, the two
consequent poles set up in the armature rotate around in its iron body at a rate
exactly corresponding to the speed of the generator. As they rotate they induce

page_text: poles in the iron of the field-magnet but these induced poles drag behind slightly, and
as opposite poles attract the armature moves in an opposite direction. Meantime the
poles in the armature have moved and the motion of the armature continues. Thus
each section of the mass of the field-magnet is in turn the seat of a rotating polar
line, and is cut by lines of force. Therefore Foucault currents are set up and their
value depends upon the resistance they meet with. The position of the field poles
induced by these eddy currents is always behind that of the armature poles the exact,
position depending on the load; the greater the load the greater the lag of the
field-poles. On the other hand the less the resistance offered these eddy currents the
smaller will this lag become in proportion. By the construction stated, the copper or
bronze bars form paths of exceedingly low resistance, and circuit is completed around
through the heads and the currents thus induced are of great strength and powerfully
magnetize the iron portions, and thus the rotary effort is increased just as if the field-
magnet were energized in the customary way. Obviously with very low resistance
in the bar circuits, a low induced electro-motive-force suffices to produce a powerful,
current which is independent of the armature current.
The same phenomena appear in a continuous current motor, when properly
arranged.
The result of the invention is that the iron pole pieces and iron winding or body of
the field-magnet become highly magnetized without any current being directly taken
from the armature circuit for that purpose and in this manner the loss in a motor or
dynamo, as ordinarily constructed, due to the circulation of these Foucault currents,
is readily utilized as a factor in the successful operation of the machine.
In some cases, where high efficiency is less important than cheapness of con-
struction, the iron bars may be omitted, and the bars of copper or bronze in that
event are all united into a cylinder.
The second part of my invention relates to devices for application to alternating
current electric motors of the differential-phase type, wherein the armature is caused
to rotate by the rotation of the polar lines set up therein by the difference of phase.
of the currents supplied to said armature. In motors of this type it has been found
that where the field-magnet is directly energized by current flowing through the
coils upon it, it is practically impossible to get the armature up to normal speed if
the field-magnets are energized at the moment of starting. The communicator has
discovered that, if the field-magnet circuit be left open at the moment of starting the
armature by the alternating currents and so continued until the armature has reached
its normal speed, the field-magnet circuit may then be closed and the full mechanical
output obtained from the motor without causing it to fall back in speed, as would be
the case were the field-magnet circuit closed at the moment of starting. This may
be explained in various ways. If we take a given pole of the field magnet and
consider that a rotating pole of the armature which we will suppose an N-pole, is
approaching the said field-magnet pole, the latter would become an S-pole and
strongly attract the said armature pole and motion of the armature would be
produced; but if the field-magnet were surrounded with its usual coils, closed, the
setting up of magnetism in the given field-pole would cause an induced current to
flow in the coil which would partially or quite annul the polarity of said S-pole of the
field-magnet. Therefore the result of these two opposing tendencies is that the
armature will not start if the field-magnet circuit is closed.
TA
1 propose to put a switch in the field-magnet circuit, but in the commercial and
widespread use of these motors, on account of the slight technical knowledge on the
part of those having them in charge, it is important to have all switching operations
performed automatically and to have their performance dependent upon the proper
conditions, so that the closing of the field-circuit will not take place until the very,
moment it is desirable that it should be closed.
I make the field-magnet switch so as to be controlled automatically by the speed
of the motor or its rotary member. This may be done in a variety of ways which,
will effect the closing only when the armature has reached its normal speed.

page_text: Thus the field-magnet circuit remains open until the armature has arrived at its
normal speed and at that instant the field-magnet circuit is closed and the motor is
in condition to exert a maximum mechanical energy.
. Obviously the arrangement of mechanical devices for this purpose may be greatly
modified without departing from the spirit of my invention as may also the electrical
devices to be used.
Dated this 4th day of Tune 1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and relating to Dynamo-electric Machines and
Electric Motors.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent Agents,
Southampton Buildings, in the County of Middlesex, 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:—
In dynamo-electric machines and electric motors generally it has hitherto been
considered essential to successful operation, either to have the field-magnet positively
energized by means of a current or currents circulating in insulated conductors
wound upon the field-magnet or else to have the field-magnets made of steel and
permanently magnetized. It has always been generally considered advisable to
laminate the pole-pieces of the field-magnets for the purpose of preventing the
generation of the Foucault currents therein. I have discovered on the contrary,
that such currents may serve a useful purpose in the motor or machine, and they may be
so concentrated and directed as to form the sole energizing-current of the field-
magnets.
My invention further relates to devices for application to alternating-current
electric motors of the differential-phase type, wherein the armature is caused to
rotate by the rotation of the polar line set up therein by the difference of phase of
the currents supplied to said armature. In motors of this type it has been found.
that where the field-magnet is directly energized by current flowing through the
coils upon it, which seems to be necessary in order to obtain an adequate mechanical
output from the motor, it is practically impossible to get the armature up to normal
speed if the field-magnets are energized at the moment of starting. I have dis-
covered that if the field-magnet circuit be left open at the moment of starting the
armature by the alternating currents and so continued until the armature has reached
its normal speed the field-magnet circuit may then be closed and the full mechanical
output obtained from the motor without causing it to fall back in speed, as would
be the case were the field-magnet circuit closed at the moment of starting. This
may be explained in various ways. If we take a given pole of the field-magnet
and consider that a rotating pole of the armature, which we will suppose
an N pole, is approaching the said field-magnet pole the latter would become
an S pole and strongly attract the said armature-pole, and motion of the armature
would be produced; but if the field-magnet were surrounded with its usual coils closed
the setting up of magnetism in the given field-pole would cause an induced current
to flow in the coil, which would partially or quite annul the polarity of said S pole
of the field-magnet. Therefore the result of these two opposing tendencies is that
the armature will not start if the field-magnet circuit is closed.
My invention further consists in a system comprising an alternating-current
generator, a pair of mains extending therefrom, one or more quarter-phase electric
motors, each having two supply-circuits, whether open or closed, one circuit
being direct from the mains and the other circuit passing through an electro-
motive device adapted to receive the line-current and change its phase so that the
currents eventually reaching the motor will be a quarter-phase apart, although
but a single generator is used and a single pair of mains.

page_text: The invention farther comprises a means of regulating such a motor.
The present invention further consists in a dynamo-electric machine (whether
generator or motor) having a closed armature-circuit tapped at three points, each of
which is connected to one of three contact-rings, such armature revolving in inductive
proximity to a field-magnet.
The invention further consists in a dynamo-electric machine constructed and
adapted to generate or absorb three currents or waves of current all differing in their
time-periods.
The invention further consists in a dynamo-electric machine constructed and adapted
to generate or absorb three currents or waves of current, each one-third of a phase or
wave-length behind its predecessor.
The invention further consists in the combination and arrangement of devices, all
substantially as hereinafter fully described.
The invention is illustrated in the accompanying drawing the figures of which are
hereinafter referred to.
Fig. 1 is a diagram illustrating one feature of my invention as applied to an
alternating-current motor.
Fig. 2 is a similar diagram illustrating the invention as applied to a continuous-
current motor.
46
Fig. 3 represents in partial cross-section an electric motor of what I term the
quarter-phase" type, having a field magnet constructed in accordance with this part
of my invention.
Figure 4 is a longitudinal vertical section of the said field-magnet without the
armature, and
Fig. 5 is an elevation of an armature of the quarter-phase type apart from its field-
magnet.
In the construction of the field-magnet I may surround the armature simply with a
cylindrical mass of iron, either cast-iron or wrought, and the effect which I have
already discovered can be produced will take place in such a plain cylindrical magnet;
but for the sake of efficiency I prefer the following construction, which is clearly
shown in Figs. 3 and 4: I first form a skeleton spool or cylinder composed of the
longitudinal bars h and heads k, leaving around the periphery a number of equidistant
slots or openings, which are filled with the iron bars i, so as to present a flush
cylindrical surface on the interior and a similar surface on the exterior, thus leaving a
space on the outside of the entire structure, which I then proceed to wind with plain
naked iron wire of any suitable size and shape, or I may wind it with hoop-iron, or it may
be constructed of thin disks of iron stamped out and slipped onto the spool. By this
construction I obtain a cylinder consisting largely of iron and having copper or high-
conductivity bronze heads and ribs extending internally between the bars of iron,
which may be considered as constituting the pole-pieces.
The armature A may be of various types; but I prefer that having a closed circuit,
as in the ring-type shown at Fig. 1, having at four equidistant points the connections 1,
2, 3, and 4, each leading to one of four contact-rings placed on the shaft, as shown at
Fig. 5 but in Fig. 11 have shown them faced on the armature for more clearly
illustrating the principle. Current is led into the armature by means of the
brushes d e f g, opposite brushes being connected to the two supply-circuits s
and s¹. These circuits supply alternating currents, the current of one being one-
quarter of a phase or wave-length behind the other, and the result is to produce
a rotation of the armature so long as the currents are supplied, and are substan-
tially one quarter phase apart in their time-periods, and in producing the rotation
of the armature the two consequent poles N and S set up in the armature rotate
around in its iron body at a rate exactly corresponding to the speed of the generator.
Suppose, now, the speed of the generator, which is of corresponding impulses, is one
thousand revolutions per minute. Then the poles N and S will traverse the armature
circularly one thousand times per minute, and suppose this motion of the poles N
and S to be right-handed, as shown by the arrows at N and S. As they rotate they
induce poles in the iron of the field-magnet; but these induced poles N" S" drag

page_text: behind slightly, and as opposite poles attract, the armature moves in a left-handed
direction, as shown by the arrow at A. Meantime the N and S poles in the armature
have moved to the right in direction and the motion of the armature continues, and
if not doing work obviously it will rise in speed until its speed nearly equals that of
the generator, and the relative motion of the poles N S and N" S" becomes so slight
as to be practically negligible. Now if work is put upon the armature (the generator
being maintained at constant speed) its speed falls, and while the relative rotation of
its N and S poles remains unaltered with respect to the armature-body the absolute
rotation with respect to a point in space changes accordingly; or, to put it in
figures, suppose the speed of the generator is one thousand revolutions per minute,
then the poles N and S travel one thousand revolutions per minute relatively to the
armature-body. If the armature speed were one thousand revolutions, the poles N
and S would stand still with respect to space-i.., their absolute rotation would be nil.
If, now, load is added sufficient to drop the speed of the armature to nine hundred
revolutions, obviously the poles N and S while still travelling one thousand revolutions
per minute relatively to the armature-body will have an absolute rotation with respect
to a point in space of 1000-900 = 100 revolutions. The direction of this absolute
rotation is, as indicated by arrows at N S, the same as the direction of relative
rotation of these poles N and S; but as this absolute rotation of the poles N S is
one hundred per minute it necessarily follows that there is a movement of the induced
poles N S in the field-magnet following the movement of poles N S, and the
speed of this movement is one hundred per minute, and each section of the mass of
the field-magnet is in turn the seat of a rotating polar line and is cut by lines of force.
Therefore, Foucault currents are set up, and their value depends upon the resistance
they meet with. The position of the field-poles N"S" induced by these eddy-currents
is always behind that of the poles N S, the exact position depending upon two things-
the load and the resistance in the metal of the field-magnet. The greater the load
the greater the lag of the poles NS", and, on the other hand, the less the resistance
offered the eddy-currents the smaller will this lag become in proportion.
By the construction stated the copper or bronze bars / form paths of exceedingly
low resistance, and circuit is completed around through the heads, and the currents
thus induced are of great strength and powerfully magnetize the iron portions, and
thus the rotary effort is increased just as if the field-magnet were energized in the
customary way. Obviously with very low resistance in the bar-circuits a low induced
electro-motive force suffices to produce a powerful current, which is independent of
the armature-current.
In this manner the loss in a motor or dynamo as ordinarily constructed, due to the
circulation of these Foucault currents, is readily utilized as a factor in the successful
operation of the machine.
In some cases, where high efficiency is less important than cheapness of con-
struction, the iron bars i may be omitted, and the bars h of copper or bronze in that
event are all united into a cylinder.
Of course in Fig. 2 it will be necessary to have contact-rings and brushes to connect
the main brushes to the external circuit while the disk p is rotating, because the latter
carries the regular brushes continuously around.
Fig. 6 is a diagrammatic view, showing a differential-phase alternating-current
electric motor arranged for self-excitation.and having an automatic switch adapted to
close its field-circuit at the proper moment. Figs. 7, 8, 9 and 10, are modifications
showing various ways in which the fundamental idea of an automatic switch may be
embodied in accordance with my invention.
Referring to Fig. 6. A is the armature of the alternating-current motor, from
which at four equidistant points connections are made, respectively, to the insulated
contact-rings 1, 2, 3, and 4, which are connected by suitable brushes to the
respective mains 5, 6, 7, and 8. Mains 5 and 6 supply an alternating current and
mains 7 and 8 supply another alternating current which, in this particular instance
differs in phase from the former by one-quarter of a wave-length. Armature A
at the other end is provided with a commutator c and brushes in the usual

page_text: manner, for taking off a continuous direct current into any circuit connected with
such brushes as described in British Patent No. 14149 of Oct. 2, 1888. Whenever
a current is admitted from the circuits 5, 6, 7, and 8 into the armature A, if the
field-magnet circuit is open, the armature will immediately start into motion and
gradually rise in speed until it substantially synchronizes with the generator,
supplying currents to the circuits 5, 6, 7, and 8; but if the field-magnet circuit
is closed the armature will not start and rise to its normal speed. I therefore
proceed as follows: I arrange an electro-magnet 9 in a suitable position and place
in front of it a pivoted armature 10, having a retractile spring 11, which tray to
advantage be adjustable, and on the arm which carries the armature 10 | arrange
a contact 12 on the side toward the magnet 9. In front of such contact I arrange
a corresponding contact 13, as shown. The field-magnet circuit is closed at all
points except the contacts 12 and 13, and my object is to accomplish the closing
of these contacts at the moment when the armature A has arrived at its normal
speed. The electro-magnet 9 is included in a branch circuit taken from the brushes b,
and including by preference a choke-coil 14, which is constructed to have a high
coefficient of self-induction and moderate resistance. This, however, is not essential
to the performance of the apparatus. Thus constructed the action is as follows:
The armature A being at rest, the two alternating currents entering the circuit of
the armature cause a rotation of the poles of the latter and set it in motion, and
at the same time, by reason of the stationary brushes b, an alternating current
passes through the branch circuit, including the coils of magnet 9.
This single
alternating current is due to and corresponds with the rotation of the N and
S poles set up in the armature A; but the current is not of such character as to
cause the attraction of the armature 10 against the force of spring 11. As the
armature rises in speed, the rotation of the poles N and S of the armature becomes
slower and slower, the waves in the branch circuit become longer and longer
and straighter and straighter, and the relay hammers slightly on its back-stop
until finally, when the speed has reached its normal rate, the current passing
through the coils of the magnet 9 is a continuous current in one direction, and
the armature 10 is attracted, causing the contacts 12 and 13 to close firmly
together and remain there so long as the armature A is rotating at its normal
speed. It is thus readily seen that the field-magnet circuit remains open until
the armature has arrived at its normal speed, and at that instant the field-magnet
circuit is closed and the motor is in condition to exert a maximum mechanical
energy.
The modification shown in Fig. 7 differs from the foregoing only in the fact that,
instead of making the motor self-exciting, I place on its shaft a continuous-current
armature A', having the commutator c and brushes 61. The field-magnet F of the
small generator is in this case preferably shunt-wound and its terminals are directly
connected to the brushes ¹. Another shunt or derived circuit 15 from the terminals
of the small generator is taken to and includes the coils of the electro-magnet 9, the
same as in the form shown at Fig. 6. The field-magnet F of the motor is supplied
with current from the small generator through its brushes b, and energizing-circuit
of the motor F is arranged to be opened or closed at the contacts 12 and 13, the same
as in Fig. 6. A retractile spring 11 is likewise used to hold the armature 10 away
from the magnet 9. The operation is as follows: The full magnet-circuit of the
motor being normally open, the armature supplied from the mains 5 6 and 7 8 starts
rotating and gradually rises in speed until its normal rate has been reached.
same time the small generating-armature A' is set in rotation, and the potential in
the branch circuit 15 gradually rises until it overcomes the force of the spring 11,
which is adjusted to yield only when the potential is a maximum due to normal speed
of rotation of the armature A. Thereupon the contacts 12 and 13 close and the
motor assumes its normal and proper condition.
At the
In the modification shown at Fig. 8 the automatic closing of the field-magnet
circuit is effected in a slightly different manner. On one or more of the cores of the
field-magnet F of the motor I wind a sufficient number of convolutions of insulated

page_text: wire, forming, with coils of the electro-magnet 9; a circuit, which I designate by the
numeral 16. In this modification the pivoted arm carrying the armature 10 of the
circuit-closing magnet is provided with a dash-pot 17, a retractile spring 11, and,
the contacts 12 and 13 are reversed in position, so as to be closed upon the retraction
of the armature 10. Upon admitting current from the mains 5 6 and 7 8 into the.
armature A the rotation of the poles of the latter sets up variations of magnetism in:
the core or cores of the field-magnet F, and these changes of magnetism induce
currents in the circuit 16 which are strongest when the armature A is lowest, because
at that time the rotation of the polar lines is most rapid and the inductive effect on:
the circuit 16 greatest. The armature 16 is therefore attracted at the first admission:▸
of current to the armature A and the circuit is open at the contacts 12 and 13.
Ass
the armature of the motor now rises in speed the attracted power of the electro-
magnet 9 gradually weakens, and by the adjustment of the spring 11 it is so arranged.
that when this attraction has reached a certain minimum dependent upon the speed of:
the motor-armature A the spring 11 will overcome the attraction of the magnet 9:
and pull the armature 10 away, thereby closing the contacts 12 and 13 and sending:
current through the field-magnet F from any suitable form of generator, such as the
battery G, shown in the drawings. When this exciting-circuit is closed, of course,
the magnetism in the field-magnet F is a constant, and no further inductive effect is
produced in the circuit 16.
In the modifications shown at Fig. 9 the general arrangement is substantially the;
same, the inductive circuit 16 being the means by which the automatic closing of the
exciting-circuit is realized; but instead of the generator 6. (shown in Fig. 8,) I have.
shown the separate exciter consisting of the field-magnet F and the armature A',
which is fixed on the shaft of the motor. The small generator A' F' thus takes the.
place of the generator G. (Shown in Fig. 8.)
In the modification shown at Fig. 10 the action of the field-magnet F of the motor i
is brought about directly by the speed of the motor acting mechanically. This is
accomplished by means of centrifugal devices on the shaft represented by the arms 18,"
weights 19, connected to the spindle 20, which is provided with the collars 21,]
between which is placed the lever 22, having. the circuit-closing contacts 12 and 13.
A spring 23 is placed around the spindle 20 in order to force open the contacts 12:
and 13, and hold them open at all times except when the speed of the armature A has:
risen to such point that the centrifugal movement of the weights 19 overcomes the
tension of the spring to such extent as to bring the contacts 12 and 13 together,,'
whereupon the field-magnet circuit is closed and the motor is brought to its propert
condition, as herein before described. Obviously the same arrangement of mechanical
devices for this purpose may be greatly modified without departing from the spirit of
my invention, as may also the electrical devices I have shown.
Fig. 11 is a diagram illustrating one of the simplest forms of my system; and
Fig. 12 illustrates the means of regulating the differential phase motor. Fig. 13:
is an end elevation showing the armature B of Fig. 11 in detail, and the arrangement
of its circuits.
:
A represents the generator of alternating currents, and 1 are the distributing
mains extending therefrom in any desired direction. B represents the armature of;
what I term the "local-phase" changer, and in the figure the armature B is a simple
drum-armature with rectifying-commutator c, on. which bear the brushes dd', and
these are respectively connected to the terminals of the field-magnets e. On the shaft:
of armature B, but insulated from the same and from, each other, are four contact:
rings fg hi, and of these the adjoining pairs fg and hi are respectively connected:
to diametrical points of the commutator c, and therefore are connected into the
armature-circuit that is to say, rings hi are connected, respectively, to two opposite:
points, and rings fg are respectively connected. to two other opposite points which:
stand at right angles to the former.
At a point conveniently located in proximity to the described phase-changing:
apparatus I place: the electric motor M, and its armature B is similar to armature B
!
:

page_text: with the exception that it has no rectifying-commutator; but it is provided with
rings k l m n, which are connected into the armature circuit of the armature B" in
exactly the same manner as the rings ghi are connected into the circuit of
armature B, and obviously, if we can supply the motor-armature B" with two currents
differing by a quarter-phase in their time-period, the motor will operate successfully
and with facility. From the branch supplying current from the mains 12 to the
rings hi of the armature B, or from the mains 12 directly, take the branch 34
and lead it to the rings m n of the armature B", so that the currents supplied to the
said rings m n is that circulating on the mains 1 2. From the contact-rings fg, I
carry a pair of leads 56 to the rings k 1, and as the current which has passed through
armature B has had its phase retarded one-quarter of a period it is obvious that the
motor-armature B will be thereafter continuously supplied with two currents, one
of which will be one-fourth phase behind the other in time period. Any number of
such motors and phase-changing devices can be connected to the main circuit 12,
and at the same time a portion of the current flowing through the mains can be used
for electric lighting or any other desired purpose.
I have shown the phase-changing device as substantially the same size as the motor,
but this merely for the purpose of making clear its functions. In practice, however,
since the armature B has no work to do except overcome its own friction and inertia
and change the phase of the current, it may be very small, irrespective altogether of
the size of the motor which it may be desired to use at any particular point, and
therefore the phase-changing devices used throughout a system of distribution of this
character may be all uniform, and being very small can be set to work in out-of-the-
way places, where they will not be interfered with. In many cases where electric
motors are used it is very desirable to be able to control their power or speed, or both.
I have devised means of doing this in connection with the above system and have
illustrated it graphically in Fig. 12. In this figure the two circuits 56 and 3 4-one
carrying a current a quarter-phase behind that carried by the other-are respectively
connected to the primary coils 7 and 8 of the converters or transformers T TH.
Each of these converters is in addition provided with three secondary coils,
respectively marked p q r and p q . The coils p p are exactly alike and are
nade with only a few turns, in order to have induced in them a very low electro-
motive force. The coils 9 q₁ are given a few more turns, so as to have induced in
them a somewhat higher electro-motive force than that induced in the coils pp".
The coils are wound with more turns still, so as to have induced in them currents
whose electro-motive force will be substantially equal to that flowing in the
branches 3 4 and 5 6.
I have herein described the transformers TT" as being provided with three secondaries;
but if a wider range of adjustment is desirable the number of secondaries can be increased
to any required extent, and the difference between them may be according to circum-
stances of use. I arrange these secondaries in connection with a switching device in such
manner that can connect the terminals of any two corresponding secondary coils
into the rings k l m n of the motor-armature B". This switch may be of any desired
construction capable of doing the work; but I show a particular form arranged to do
the double switching of each pair of coils simultaneously. This switch consists of a
pivoted bar P, carrying metallic contact-arins vw, and in the path of the arms I
arrange the respective contacts 9 10 11 and 12 13 14. The ring k of the motor-
armature is directly connected to the corresponding terminal of each of the secondary.
coils p gr, and the ring m is likewise directly connected to the corresponding
terminals of the secondary coils p"q". The remaining terminals of the coils p gr
are respectively carried out to the contacts 9 10 11. of the switch, and the similar
remaining terminals of the coils p q r of the transformer T are carried out to
the switch-contacts 12 13 14. The remaining rings I and n are joined by flexible
connections to the contacts and w of the switch-arm P. Thus arranged each of the
transformers T T operates independently of the other. So far there will be no
conflict, owing to the fact that the currents in the circuit 56 are one quarter-phase
1.

page_text: behind the currents in the circuit 3 4. Supposing, now, the motor-armature B¹¹¹ is
at rest and the switch-bar P is not resting upon any of the contacts, none of the
secondary circuits of either of the transformers is closed, and consequently no work
will be done under these conditions. If, now, we want to start the motor, I swing
the arm P into contact with the points 9 and 12 of the switch. This at once closes
the circuit of secondary coil p into the armature B₁ through the contact-rings k 1,
and at the same instant it likewise closes the circuit of the secondary coil into the
armature B through the contact-rings m n, since in the transformation which takes
place, if any retardation of phase occurs in the secondary currents, the secondary
coils in both transformers will be affected in the same degree and will have the same
time relation to each other as the currents in the primary coils, and it follows from
the foregoing that the armature B" will now be supplied by the converted currents
under the same conditions of difference of time-period in the supply-circuit of the
motor, and consequently the latter will be operated as before. If it is desired to give the
motor more electro-motive force, I swing the switch-bar Ponto the contacts 10 and 13,
and now the coils q q₁ receive the inductive effect and supply the resulting electro-
motive force to the armature B". Should it be desired to provide the armature with
an electro-motive force still higher, I swing the bar P onto the contacts 11 and 14,
and now the inductive effect is produced through the secondary coils r".
suitable construction of the secondary coils of the transformers T T", I can supply the
motor-armature B" with any electro-motive force which may be desired, whether the
same be below or above that of the primary circuits, and thus I can effect any
condition of current which may be required in any particular case.
By
Figs. 14 to 19, inclusive, show diagrammatically a generator in six equal and
successive portions of one revolution. Figs. 14 to 193, inclusive, show the corre
sponding phases produced in the external circuits. Fig. 20 is a completed diagram of
the phases occurring during the one revolution. Fig. 21 is a simple diagram
representing my invention applied to a two-pole machine. Fig. 22 is a diagram
showing the construction of the generator when intended for self-excitation. Fig. 23
is a diagram representing the manner of connecting a closed-circuit armature to give
three series of alternating currents and three external circuits adapted to utilize them
separately. Fig. 24 is a diagram showing a generator and motor, both self-excited,
and the connecting-circuits.
Referring to Figs. 21, 22, and 23 it will be seen that I can use a simple ring-
armature A with continuous winding closed on itself, the armature being placed for
revolution in the field N S, which may be excited by the rectified current of the
armature or a shunt thereof, or by a separate exciter, or by any of the usual or known
methods. I select three equidistant points a, b. and c of the armature-winding and
connect them to the contact-rings de 1, which are shown as fitted against the end of
the armature, but will in practice be on the shaft, as in Fig. 24. Separate
brushes hear on the rings and, being three in number, are capable of
forming three distinct pairs of circuits for external distribution with only three
wires.
By reference to the operation disclosed in Figs. 14 to 19 and 14 to 19ª, inclusive,
and Fig. 23, the peculiar action of the generator will be understood. The diagrams,
Figs. 14 to 19", show the three partial phases produced during the sixth of a revolution
of the armature which each diagram represents. If we now consider (see Fig. 23) each
of the brushes ghi connected to one wire of a three-wire external circuit kl
9
m, it
will be seen that the latter may form three pairs kl, m, and I m, and in each pair con-
sumption or translating devices-for example, lamps n-may be connected. Upon now
tracing the diagrams in connection with Fig. 23 it will be seen that each of the three
external circuits will be a path for a distinct series of alternations. The three sections
of the armature A will deliver, respectively, the alternations or waves of current
indicated on the diagrams by a b, a c, and be, and each set of waves will be complete
and continuous, but will be behind one another in their time-periods to the extent of
one-third of a phase or wave-length. If, then, the three external circuits be closed,
B

page_text: each will receive a single set of alternations and serve for lighting and other
distribution purposes and the current-strengths will depend upon the resistances in.
the circuit.
In my said former patent I have shown that an alternating-current generator with
two pairs of collecting devices ninety degrees apart greatly increase the output
capacity of a given machine owing to the quarter-phase difference between the
alternations. In the present case, with only three collecting devices, the output
capacity is still more increased by reason of the alternations differing by a third of a
wave-length. Obviously, instead of the lamps n in Fig. 23, I can substitute the
primary coils of converters p and place the lamps or other consumption devices in the
secondary circuits of the converters, as indicated also in the same figure.
When two such machines are connected together, as shown in Fig. 24 whether
their field-magnet be energized by rectified currents or otherwise, the first being
power-driven, the second machine will operate as a motor in a manner, so far as
rotation is concerned, similar to the rotation of the motor set forth in my said patent.
I have shown the generator G and motor M as substantially alike, and each with a
rectifying-commutator for delivering direct current to the field-magnets similarly to
the plan illustrated by the diagram Fig. 22. The three connecting-circuits will in
this case, as in Fig. 23, constitute three different circuits, and will be delivered into
the motor-armature in such manner as to throw into the same in succession three
separate series of current alternations, each of which will be substantially one-third of
a wave-length behind the series preceding it, and will therefore determine the
rotation of the armature, as described in my former patent.
When the current is admitted to the armature of the motor it is difficult to start
the latter when the field-magnet circuit is closed, whether the latter be supplied with
its exciting-current, from the mains or from an independent source; but, if at the
moment of introduction of current into the armature-circuit the circuit of the field-
magnet be left open, the armature will readily start into rotation and quickly rise in
speed until it synchronizes with the generator, and the field-magnet circuit can then
be closed and the operation of the armature will continue under its best conditions
and remain at the speed of the generator.
In Fig. 24 I have shown the field-magnet of the motor as being excited by the
currents from the main circuits rectified by a commutator, and in this field-magnet
circuit locate a switch s for the above purpose.
Obviously electro-motive devices similar to the motor shown in Fig. 24 may be
inserted in the circuits k l m and the entire current can be rectified by means of the
armature A and its commutator and brushes, from the latter of which the rectified
and continuous current may be delivered to any desired translating or consumption
device such, for instance, as a continuous-current motor, an electroplating-bath, an
arc lamp, or other device adapted to use with a continuous current. It is also obvious,
as set forth in my above-mentioned patent, that continuous currents delivered to such
an electro-motive device and passing in at the commutator-brushes can be split into
three series of alternating currents of differing phase and delivered to the brushes ghi,
which bear on the contact-rings d e f, and thence to the desired consumption
<levices.
I thus obtain the best possible results from an alternating-current machine with the
least possible number of distributing or supply wires. This is due to the two features
of closed armature-circuit and trisected winding. The latter determines the one-third
phase difference in the series of alternations or waves, and the former permits three
separate external circuits to be established on only three wires, while the potential of
all three will be substantially alike. Were the armature-circuit made up of three
separate coils, six wires would be required in the external circuits to accomplish the
same results. Were the armature-circuit quadrisected, as in my previous patent, two
separate circuits can be established with three wires, one being a common return for
the other two; but only two independent currents can then be generated, each
supplementing the other. It is true that with the quadrisected armature two currents

page_text: are obtainable, each of which may be practically as great in strength as the machine
would stand if produced in the ordinary way; but it is also true that with my
present trisected armature three currents are obtainable, each of which may be
practically as great in strength as the machine could generate with a four-coil or.
quadrisected armature, and this I accomplish with three separate external circuits
composed altogether of but three wires. This I hold to be the maximum result with
the fewest components of external circuit.
'
In the claims I use the term "current-leading device" as expressive of the means
of connecting the machine to the external circuit, whether such means be rings and
brushes or commutator and brushes, or both, or simple fixed connections. The last
would obviously be sufficient in case I reverse the arrangement of the machine,
making the armature stationary and the field-magnet movable.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, as communicated to me by my
foreign correspondent, I declare that what I claim is :—
1. An electric motor comprising a field magnet adapted to be energized by the
eddying currents due to the rotation of the poles of the armature, in combination with
an armature having magnetic poles rotating independently of its motion.
2. An electric motor comprising a field-magnet adapted to be energized by the
eddying currents due to the rotation of the poles of the armature, in combination
with an armature having magnetic poles automatically rotating independently of its
motion.
3. An electric motor having an armature with insulated winding thereon and
connections for the external circuit or circuits, in combination with a field-
magnet disconnected from the armature and external circuits, and wherein the
effective poles depend for existence on eddying currents circulating in its body.
4. In an electric motor, an armature constructed with no dependently-rotating
magnetic poles, in combination with a mass composed partly of a magnetic metal and
partly of a low-resistance metal placed in continuous inductive proximity to the
armature and constituting its field-magnet.
5. In an electric motor, a rotary armature having independently-rotating magnetic
poles, in combination with a surrounding compound annulus, partly iron or steel and
partly of a low-resistance metal, the latter arranged in bars or sections parallel with
the winding on the armature.
6. A compound annular field-magnet having its surface adjacent to the armature
composed of alternate bars of iron or steel and a low-resistance metal-such as copper
or bronze-substantially as described, whereby said low-resistance bars form paths
for currents.
7. A compound annular field-magnet having its surface adjacent to the armature
composed of alternate bars of iron or steel and a low-resistance metal-such as copper
or bronze-and having the ends of said low-resistance bars connected to low-resistance
heads or cross-bars, substantially as described.
8. A field-magnet composed of alternate bars of magnetic metal and low-resistance
metal laid together to form a cylinder and bound externally with magnetic metal,
which serves to retain the structure in form and complete the magnetic circuit.
9. A field-magnet composed of alternate bars of magnetic metal and low-resistance
metal laid together to form a cylinder and wound externally with iron or steel
wire.
10. In an alternating-current electric motor having an induced field-circuit, the
combination therewith of an automatic switch adapted to close said field-circuit on
arrival of the armature at its normal speed.
11. In an alternating-current electric motor having an induced field-circuit, the
combination therewith of an automatic switch adapted to close said field-circuit and
means for closing said switch on arrival of the armature at its normal speed.
12. In an alternating-current electric motor having an induced field-magnet, the

page_text: combination therewith of a switch adapted to close the field-circuit, means for holding
said switch open till the armature arrives at its normal speed, and means for thereupon
closing said switch automatically.
13. In an alternating-current electric motor having a rotary armature and its field-
magnet provided with an energizing-circuit, the combination therewith of a switch
in said field-circuit and means for automatically closing said circuit, dependent for
operation upon the armature attaining its normal speed.
14. In an alternating-current differential-phase electric motor having a rotary
armature and its field-magnet provided with an energizing-circuit, the combination
therewith of a switch in said field-circuit and means for automatically closing said
circuit, dependent for operation upon the armature attaining its normal speed.
15. In an alternating-current electric motor comprising a stationary and a movable
member, one of which has polar rotation set up in it by direct action of the
operating-current and the other member has an energizing-circuit, the combination,
with the said energizing-circuit, of a switch for, opening and closing the same, and
means for automatically closing said switch controlled by the speed of said movable
member of the motor.
16. In a system of electrical distribution, the combination of a generator of
alternating currents, a pair of mains connected thereto, one or more multiple-circuit
differential-phase electric motors having one circuit connected directly to said mains
and the other circuit or circuits connected to said mains through an interposed
electro-motive phase-changing device adapted to change the time period of the currents
passing through it.
'
- 17. In a system of electrical distribution, the combination of a generator of
alternating currents, a pair of mains connected thereto, one or more double-circuit
quarter-phase electric motors having one circuit connected directly to said mains,
and the other circuit connected to the said mains through an interposed electro-
motive device adapted to change currents passing through it at one-quarter of a phase
or wave length.
18. The combination, with a quarter-phase double-circuit electric motor, of two
transformers, each composed of a primary coil connected to the supply-circuit, and
two or more graduated secondary coils connected to the motor-circuit, and means for
switching said secondaries in matched pairs into the motor-circuits, substantially as
described.
19. The combination, with an alternating-current double-circuit electric motor, of
one or more transformers having primary coils connected to supply-circuits, and two
or more graduated secondary coils adapted to be connected to the motor-circuits,
and means for connecting said secondary coils into the motor-circuits as required,
substantially as described.
20. The combination, with a multiple-circuit alternating-current electric motor, of
two or more supply-circuits having their currents of respectively differing phase, two
or more primary or inducing coils respectively included in the supply-circuits, two
or more graduated sets of secondary coils in inductive relation to said primary
coils, and a switch adapted to connect the respective motor-circuits to any pair of
said secondary coils.
21. The combination, with an alternating-current dynamo-electric machine adapted
to generate and deliver three separate series, of alternations differing in their time-
periods by one-third of a phase, of three external circuits composed in all of three
conductors permutated into said three circuits, and consumption devices located in
said external circuits.
22. In an electro-motive device, the combination of a field-magnet and a rotating
armature provided with a current-rectifying commutator and brushes therefor,
through which current is received into the armature and rotation produced in the
moving part of the machine, three current-leading devices on the one hand connected,
respectively, into the armature-circuit at equidistant points and so arranged relatively
as to lead off three independent series of alternating currents substantially one-third

page_text: of a phase apart in their relative time-periods, and on the other hand connected with
three conductors permutated into the said three circuits, and consumption devices.
located in each of the three circuits.
Dated this 2nd day of April 1890.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant