IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES
Year: 1883

page_text: LETTERS PATENT to Henry Harris Lake, of the firm of Haseltine, Lake,
"
and Cº, Patent Agents, Southampton Buildings, London for an Invention
of "IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES Communicated to him
from abroad by George Washington Fuller, of Norwich, Connecticut, United
States of America
COMPLETE SPECIFICATION filed by the said Henry Harris Lake at the
Office of the Commissioners of Patents on the 12th March 1883.
IN DYNAMO - ELECTRIC
HENRY HARRIS LAKE, of the Firm of Haseltine, Lake, & Co, Patent Agents,
Southampton Buildings, London " IMPROVEMENTS
MACHINES" communicated to me from abroad by George Washington Fuller,
of Norwich, Connecticut, United States of America
This Invention relates to improvements in dynamo-electric machines which
improvements are designed to increase the steadiness of their operation and add to
their efficiency.
I increase the steadiness of operation by rotating the field magnets; and I add
to the efficiency of the machine, by making the armature core independent of the
coils which surround it, and by keeping all parts of the core in unchanged polar
relation to the field-magnets.
The field magnets by reason of their mass, serve, when in rotation, the mechanical
purpose of a balance wheel. Their momentum renders the machine less sensitive
in responding to sudden changes in the energy of the force which drives it, or to
sudden variations in the resistance of the working circuit.
The unchanging position of the poles in the armature core gives time, during the
continued operation of the machine, for the highest possible magnetization of the core,
which, by concentrating the magnetic lines of force and intensifying the magnetic field
or fields, adds to the energy of the electrical pulsations generated during the bisection
of the lines of force by the armature coils. This bisection, according to the said
invention, may be brought about either by rotating the armature coils while
holding the field magnets and the armature core stationary, or, by rotating the field
magnets and the armature core in one direction, while rotating the armature coils
D971

page_text: in the opposite direction, or by holding the armature coils stationary while the
field magnets and armature core are rotated, which latter method of operation is
that which I have selected for the purposes of the present illustration of my
invention.
My improvements are capable of embodiment in alternating current machines,
or in machines generating currents of constant polarity; in machines in which the
armature core, loosely surrounded by the armature coils, is rotated by the magnetic
attraction of rotating field magnets; and, in machines in which the armature core
is rotated by directly applied mechanical power.
According to a modification of my invention hereinafter described with reference
to an alternating current machine the field magnets are peculiarly arranged, and
the armature core is rotated by magnetic force. The said armature core is an
annulus, substantially triangular in cross section, with shallow recesses extending
across its periphery and its inwardly bevelled sides whereby a series of polar
prominences are formed corresponding in number and relative positions with the
number and relative positions of three rotating.circles of field magnets.
The armature coils, wound in triangular shape to conform to the shape of the
core in cross section, are arranged radially in conveniently close proximity to each
other, and are stationary.
Gaps of sufficient width are left in the circle of stationary armature coils, to
permit the bearing of the annular core upon internally placed friction rollers, by
means of which the annular core is supported concentrically with relation to the
axis of the rotating magnets.
Three series of field magnets, the coils of which are connected in the same circuit,
are arranged in circles in parallel planes, with their axes respectively 'perpendicular
to the periphery and to the two bevelled sides of the annular core. The field
magnets are affixed to the interior of a suitably formed cylinder mounted upon,
and affixed to, a revolving shaft provided at one end with a pulley, or preferably a
crank, to which power is applied, and carrying at its opposite end a contact-maker
in two parts, which are respectively connected with the ends of the field circuit,
and make contact respectively with brushes connected with an outside machine by
which the field is charged.
The field magnets are arranged radially in groups of three.
Their coils are so
wound and so connected, that the poles of the magnets composing each group are
of like polarity to each other, but are of opposite polarity to the poles of the next
adjoining group on either side.
The armature core, being free to move, is, by reason of its polar prominences,
dragged around by magnetic attraction as the field magnets revolve.
By the rotation of the field magnets there is excited in each of the stationary
armature coils a succession of electrical impulses alternating in polarity, and each
of the stationary armature coils may, if desired, be employed to supply an outside
circuit with an alternating current; or variable numbers of stationary coils, which
are subjected to the same electrical conditions at the same times, inay be connected
together in series, and made to cumulatively supply an outside circuit.
The field magnets and the rotating shell to which they are attached constitute a
structure of such massiveness, that it serves the purpose of a balance wheel, which,
by its own momentum, greatly promotes the steadiness of the machine, and hence
the induction in the armature coils of currents of uniform strength.
By reason of the weight of the rotating structure the shaft may receive its
motion directly from a steam cylinder, or the machine may be affixed to the crank
shaft of an engine and thus all intermediate shafting, belting, or gearing may be
dispensed witb.
During the operation of the machine the magnetic attraction exerted upon all
parts of the armature core tends to centralize, and sustain it, and as the core is
free to move, I have, as a matter of convenience, adopted for it the designation
"Floating core."
If the armature core should be so fastened as to prevent its movement the

page_text: Dy perming
10
rotation of the nela maguets would cause it to become heated.
to move in obedience to the magnetic forces to which it is subjected, the machine
may be rotated at a high speed without heating the armature core.
In the accompanying drawings
Figure 1 is a front elevation, and
Figure 2 is a side elevation of a machine constructed according to the said
Invention.
Figure 3 is a side elevation, drawn to an enlarged scale, of the contact maker and
contiguous parts.
Figure 4 is a central longitudinal section of the contact maker, the end of the
shaft upon which the contact maker is mounted, and the contiguous portions of
the bearing of the shaft, showing the method of effecting the electrical connection
with the free ends of the circuit which includes the rotating field magnets
Figure 5 is a side elevation of the annular floating core.
Figure 6 represents a portion of five stationary coils showing the method of
connecting them when they are each composed of a double system of coils
Figure 7 is a central longitudinal section of the machine showing the method of
constructing the revolving shell which supports the field magnets and the method
of supporting the floating armature, and the inner frame to which the stationary
coils are affixed.
Figure 8 is a front elevation, partly in section, of the interior of the machine
with one side of the revolving shell, and the circle of field magnets supported
thereon removed
Figure 9 is a diagram displaying the three circles of field magnets in the same
plane, for the purpose of illustrating a method of appropriately connecting their
coils in a single circuit
The machine is supported upon a substantial base A, to which are bolted the
standards A' at the top of which the shaft B of the machine has its bearings.
The rotating shell which carries the field magnets is composed of three principal
parts, namely the corrugated annular plate C, the short cylinder D, and the
annularly-corrugated disc E provided with a hub E' which is keyed to the shaft B.
The outer edges of the plate C and the disc E are secured respectively to the
opposite ends of the short cylinder D, by means of the screws C¹ and D¹.
It will be seen that in cross section the relative angles of the inner faces c, d,
and e, of the shell to which the three circles of field magnets F, F', and F" are
respectively affixed, are those of an equilateral triangle.
The field magnets are concentrically arranged in equidistant groups of three, the
members of each group occupying the same radial plane.
The armature coils G which are stationary and are wound in the form of
triangles, are concentrically arranged flatwise in radial planes in three groups as
shown in Figure 8. The three sides of each stationary coil occupy the most intense
parts of the magnetic field, that is to say, the parts immediately adjoining the paths
of movement of the poles f, f' and f' of the rotating field magnets. The stationary
coils are supported in position by means of the screw clamps G1 G2 which confine
the outer corners of the coils to the rings h and H respectively, of the stationary
armature frame composed of the three radial arms H H H the outer portions
of which occupy the spaces between the three groups of stationary coils. The
radial arins H are united to a central hub H³ which is secured by means of the
screws H³ to the inner end of the front journal box B¹ of the shaft B. The ring H
is secured to the outer edges of the arms H' and the ring his partially supported
in position by being screwed to the rear ends of the three suitably curved plates h¹
the front ends of which are secured to the ring H or to the outer ends of the
arms H¹ respectively. Three arms h³ extend radially inward from the ring hat
the three points immediately opposite the arms H¹ to which the arms h³ are
secured by means of suitably shouldered bolts inserted through ears I formed
on the sides of the arms H₁ respectively and corresponding ears formed on the
arms h³.

page_text: The shape in cross section of the arms H' and his exhibited in Figure 7, from
which it will be seen that the bends in them are such as to afford clearance on
either side for the inner circles of the rotating field magnets F and Fª.
The arms Hand h³ afford the bearings for the friction rollers K, K, K, the
peripheries of which are provided respectively with the grooves k for engaging with
the inner edge of the floating core L, which is an annulus, substantially triangular in
cross section, made with a removable sector L' to permit the core L in the process
of constructing the machine, to be inserted through the triangular armature coils G
by which the core is segmentally enclosed. The three faces of the core L, are
transversely recessed to form the equidistant polar prominences 7 which correspond
in number and relative positions with the number and relative positions of the
poles of the field magnets.
On reference to Figure 8 it will be seen that the armature coils G of each
group are symmetrically placed so that when one coil is interposed between
the three poles of one group of field magnets another coil is at the same time
interposed between the three poles of the next adjoining group of field magnets,
and so on.
The spaces between the members of each group of field magnets constitute
a series of radially related magnetic fields, having an orbital motion by virtue
of the rotation around a common centre of the magnets by which the fields are
excited. The field magnets are so wound and connected that each field is of the
opposite polarity from the fields which adjoin it on either side.
The polar prominences upon the faces of the floating core, by reason of their
closer proximity to the poles of the field magnets, are more forcibly attracted
than the recessed parts of the core, the result of which is that the core is dragged
around by the magnetic attraction of the field magnets, and the parts of the core
where the polar prominences are situated are polarized by induction and retain
their respective polarities without change during the operation of the machine.
Ey this organization of the machine the stationary armature coils are successively
subjected to the action of magnetic fields alternating in polarity, and a single coil
may be employed to supply an cutside circuit with an alternating current, or
variable numbers of coils may be connected together and made to act cumulatively
in supplying the same outside circuit.
Thus for example, four independent outside circuits may be supplied with
alternating currents by connecting the stationary coils in the manner shown in
Figure 8, in which the four circuits and the systems of coils embraced in each
circuit are indicated respectively by the Figures 1, 2, 3 and 4. In this case each
circuit includes a series of twenty two coils, and the connections are made by
joining the first convolution of one coil to the first convolution of the next
preceding coil of its series, and its last convolution to the last convolution of the
next following coil of its series, the first convolution of the last mentioned coil
being joined to the first convolution of the next following coil of the series, and
BO on. The relatively opposite polarities of the adjoining fields render this mode of
connection necessary in order that simultaneous electrical impulses induced in
opposite directions in adjoining coils of the series may be made to flow cumu-
latively into the outside circuit which the series supplies.
It will be obvious that eight independent circuits might be established by con-
necting together every other coil of each of the described series; in which case the
last convolution of each coil would require to be joined to the first convolution of
the next coil in its series, and so on; the principle governing the mode of con-
necting the coils in the last case being the reverse of that previously described
because the several coils included in each of the said eight circuits would be
simultaneously acted upon by fields of like polarity.
The stationary coils G, instead of being formed of one continuous wire, may be
composed of two independent wires wound in similarly shaped convolutions, and
superposed as indicated in Figure 6, which shows one method of connecting systems
of double coils. This modification doubles the number of independent coils and

page_text: correspondingly increases the number of possible independent circuits which the
machine is capable of supplying with alternating currents.
The field magnets which are connected in series in a single circuit are excited by
a current from an outside source, transmitted by means of the contact maker M,
composed of the two insulated discs m, and m³, carried upon the shaft B, These
discs have their peripheries grooved to respectively receive the brushes N, N',
supported upon the arms n, n¹ with which the wires of the outside circuit are
respectively connected.
The ends of the field circuit wires O, and O¹, are connected respectively with the
contact discs m, and m³, as shown in Figure 4, and are carried through a hole
extending longitudinally partly through the centre of the shaft B, thence outwardly
through one side of the shaft, and through the hub E¹, to the field magnets in the
interior of the machine as shown in Figure 7.
1
In joining the coils of either of the circles of field magnets, the connections must
be so made that the exciting current will flow in one direction through the coil of
one magnet, and in the opposite direction through the coil of the next adjoining
magnet in the circle, and so on, as is well understood by those who are familiar
with dynamo-electric machines.
ע
As has already been observed the several circles of field-magnets must be so
connected that the magnets of each group will present poles of like polarity to each
other, but of opposite polarity to that of the adjoining groups on either side.
''
The connection between the rear circle of field magnets supported upon the
discs E and the middle or outer circle of magnets, supported upon the cylinder D,
and the connection with the wires leading to the contact maker, can easily, be
made before the annular plate C is secured in position. To effect the connection
with the front circle of field magnets supported upon the annular plate, C, an
aperture provided in the edge of the plate C, at any convenient point through, or
near, which the ends of the wires leading from the middle circle of magnets are led,
so that they can be appropriately coupled to the ends of the wires leading from the
front circle of field magnets after the plate C, affixed in place.
C
A mode of connecting the field-magnets is illustrated in Figure 9, which is a
diagram representing as projected on the same plane the three series of field
magnets which in the machine, are arranged in circles in parallel vertical planes.
It is not deemed necessary to show the entire number of magnets contained in
each circle, inasmuch as eight, the number shown, suffices to illustrate the mode of
connection.
The coils of each series of field magnets are connected together in the same way
as the stationary coils of a series are connected together, that is, by joining the
first convolution of one coil to the first convolution of the next preceding coil of its
series, and its last convolution to the last convolution of the next following coil of
its series, the first convolution of the last mentioned coil being joined to the first
convolution of the next following coil, and so on.
In the diagram the three parts C, D, E, of the rotating shell upon which the
field magnets are supported are not represented, and the letters C, D, E, appearing
upon the diagram serve merely to indicate the circle of 'field magnets which the
three parts of the rotating shell respectively support.
The shell carrying the field magnets may be rotated by means of a belt acting.
upon a pulley affixed to the shaft B, or a crank may be fixed on the rear end of
the shaft B, to be actuated by the pitman or connecting rod of a steam engine by
which the machine may be driven.
In the present machine the floating armature core is an annulus, and the
stationary armature coils surround it segmentally
7760
I will now describe my invention as embodied in a charging machine for
generating a current or currents of constant polarity, retaining the general features
of the machine as herein before described.
2
field
The armature core ja rotated by the magnetic attraction of the rotating, field

page_text: magnets, and is centralized and supported by three wheels having their bearings in
the radial arms of the frame which supports the stationary coils. In this case,
however, the weight of the armature core is supported upon the main shaft of the
machine by means of adjustable wheels which are interposed between a loose
wheel on the shaft and three exterior wheels upon the peripheries of which the
inner edge of the armature core has its bearings.
I arrange the stationary coils concentrically in three groups, which are
respectively contained in the spaces between the radial arms of the stationary
frame.
In the drawings I have shown these coils as connected up in two circuits, each
containing an equal number of coils, with two commutators, one for each circuit,
one circuit being employed for charging the field magnets, and the other for outside
work. It is obvious however that a greater or less number of coils may be
included in the two circuits shown, or that all of the coils may be connected up in
a single circuit which includes the coils of the field magnets.
This part or modification of my invention is illustrated in Figures 10 to 15.
Figure 10 is a side elevation of the commutators, brush holders, and brushes,
drawn to an enlarged scale.
Figure 11 is a central longitudinal section of the commutators and the end of
the shaft upon which the commutators are mounted, together with a diagram
illustrative of the circuits.
Figure 12 is a transverse section drawn to a still larger scale, of one of the
commutators, showing the number and relative location of the different commutator
strips.
Figure 13 is an elevation, partly in section, showing the interior of the machine
with the front circle of field magnets removed.
Figure 14, is a side elevation of the armature core.
Figure 15 is a section on the line Y Y Figure 13, showing the principal portion
of the rotating shell, and the arrangement of the groups of field magnets with
relation to the annular armature core and stationary coils, together with the
system of friction wheels by means of which the weight of the rotating core is
supported upon the shaft of the machine, and the core is centralized.
The general construction of the machine does not differ essentially from that first
described, and in the figures illustrating this second part or modification of my
invention, the same letters indicate corresponding parts of the first machine, but in
this part of my invention the wheels k, k, k, which afford the bearings for the
floating core, are mounted loosely upon their shafts k¹, k, k¹. At their ends these
shafts have their bearings in the slots k, formed in the arms H¹, h³ of the stationary
internal frame.
The hubs of the wheels k are provided with the grooves k³, for engaging with
corresponding tongues formed upon the peripheries of three intermediate
wheels K, also mounted loosely upon their shafts k³. The shafts have their
bearings in the curved slots formed in the arms H¹². The peripheries of each
of the wheels K¹, are also provided with the additional tongues k7, which engage
with the grooves a formed in the periphery of the central wheel K* mounted
loosely upon the shaft B. The curved slots are concentric with relation to the
shaft B, while the slots k³, in which the shafts k¹ of the outer series of wheels have
their bearings, respectively, are radial with relation to the shaft B.
By means of the set-screws K, inserted transversely through the arms H¹, h³, and
bearing respectively upon the bottoms of the grooves K, formed in the shafts k³ of
the adjustable wheels K¹, those wheels are capable of adjustment in a path which
is concentric with the shaft B.
It will be seen that the axes of the adjustable intermediate wheels are not in
radial alignment with the axes of the exterior wheels k, k, k, and the central
wheel K, and hence that by moving either of the intermediate wheels K¹ laterally
toward or from the radial line which bisects the axis of the central wheel and the

page_text: axis of that one of the exterior wheels which bears upon the intermediate wheel,
the exterior wheel is in the one case forced radially outward from the shaft B, and
in the other case is permitted to assume a position nearer the shaft B.
By means therefore, of the three adjustable wheels K', K¹, K' the annular core
can be perfectly centralized and supported in position, while its weight is supported
directly upon the shaft B of the machine.
The diameters of the systems of wheels are so proportioned that the speed of
rotation of the core L is the same as the speed of rotation of the central wheel K³,
when that wheel is moving with the shaft B without slipping thereon.
The object of having the central wheel loosely mounted is to provide for the
slipping of that wheel upon the shaft B when the machine is being stopped, so that
there will be no grinding of the bearing surfaces of the supporting wheels, such as
might be caused by variations in the relative speeds of rotation of the core L,
and the shell carrying the field magnets while the machine is coming to rest.
The field magnets are excited by a current derived from any desired number of
the stationary armature coils, which current is rendered constant in polarity by
means of a suitable commutator.
The remainder of the stationary armature coils may be employed either singly
or coupled together, to supply a current or currents of alternating polarity to an
outside circuit or circuits, or, by means of another commutator, may be made to
supply an outside circuit with a current of constant polarity.
This is illustrated in the drawings, by a division of the stationary coils into two
series, the members of which are coupled together, and form two circuits, one of
which supplies the current to excite the field magnets while the other supplies an
outside circuit.
It will be seen that there are an equal number of stationary armature coils, and
that, regarding the machine as stationary, those of the coils which are in the same
radial plane as the field magnets are included in one circuit, while the remainder
of the stationary coils, which occupy the intermediate radial planes, are included
in the other circuit.
In connecting the stationary coils of each circuit, the same method is pursued as
in connecting the coils of either of the circles of field magnets. Thus, the first
convolution of one coil is connected with the first convolution of the coil
immediately preceding it in the series to which it belongs, its last convolution
being connected with the last convolution of the coil next immediately following it
in the series, the first convolution of the last mentioned coil being connected with
the first convolution of the next following coil and so on. For convenience, the
interior portion of the circuit which supplies the current for exciting the field
magnets is indicated by Figure 11, while the interior portion of the other circuit is
indicated by Figure 12.
It will be seen that the terminal O₁ of the circuit which includes the coils of the
field magnets is carried through a central hole in the shaft B, and is electrically
connected with the part m² of the commutator M, which is mounted upon the end b
of the shaft B. The terminal O of the field coil circuit is led through the shaft B
in like manner, and is connected with the contact wheel m³.
The two parts of the commutator M, which are insulated from the shaft and
from each other, are each in the shape of a crown-wheel having long rectangular
teeth, and each having a number of teeth equal to one half the whole number of
groups of field magnets. The teeth of the crown-wheels forming the two parts
of the commutator M are interplaced, the two crown-wheels being insulated from
each other in the usual manner.
The current for charging the field magnets is supplied by the circuit N° 1, the
two terminals m and m¹ of which are respectively connected with the brushes o
and o', which bear upon opposite sides of the commutator M. One part M' of the
commutator is electrically connected with the contact wheel M², the other part m³
of the commutator being electrically connected, as already stated, with the
terminal O¹ of the circuit which includes the field coils.

page_text: If the circuit N° 1 embraces a number of stationary coils no larger than is
required for charging the field magnets, the terminal O may be electrically
connected directly with the contact wheel M. If, however, the circuit N° 1
furnishes a current which is more than is required for charging the field magnets,
the surplus may be employed in an outside circuit. This is effected by means of
the brushes N and n bearing respectively upon the contact wheels m³ and M.
The brushes N and n are respectively sustained by the brush holders N¹ and n¹
which are electrically connected with the terminals of an outside circuit N'.
The arrows marked 1 on Figure 11 indicate the complete course of the circuit for
charging the field coils and for supplying the outside circuit N.
.
The terminals P and p of the circuit N° 2, which includes the remainder of the
stationary coils, are electrically connected, respectively, with the brushes m' and m³,
which bear upon the periphery of another commutator R mounted upon the end b
of the shaft B and similar in construction to that already described, with the
exception that the two parts rand of the commutator R are electrically
connected, respectively, with the two rotating contact wheels S and 8, the grooved
peripheries of which make contact respectively with the terminals T and t of the
outside or working circuit P'.
The course of the circuit N° 2, is indicated on Figure 11 by the arrows
marked 2.
It will be seen that the poles ff' and f* of the rotating field magnets are pieces
the areas of which are larger than the cross section of the cores, and that the
widths of the polar prominences upon the armature correspond to the widths of
the poles f, f and f*. The object of this construction is to elongate each field in
the direction of its path of motion, and thus give more time for each of the alternate
inductive actions of the field upon the stationary coils.
Having thus fully described the said Invention as communicated to me by my
foreign Correspondent, and the manner of performing the same, I with it understood
that I claim.
First-In a dynamo-electric machine, the combination of the field magnets with
armature coils, the convolutions of which loosely surround a core of magnetic
material, all the parts of which core sustain unchanging polar relations to the field
magnets, substantially as, and for the purpose, set forth.
Second The combination in a dynamo-electric machine, of armature coils with
rotating field magnets, and an armature core capable of rotation independently of
the said armature coils, as, and for the purpose, set forth
Third The combination in a dynamo-electric machine, of systems of rotating
field magnets and stationary armature coils with an armature core adapted to
rotate independently of the coils which surround it, and having formed upon its
face or faces transverse polar prominences, substantially as, and for the purpose,
set forth.
:
Fourth In an alternating current dynamo-electric machine, three systems of
field magnets, supported respectively in three circles upon the interior of a rotating
shell, and forming a series of radially arranged groups, each composed of three
magnets, the three magnets of each group being of like polarity to each other, but
of opposite polarity to that of the adjoining groups, and presenting their poles in
close proximity to, and parallel with, the three sides respectively of triangular coils
transversely surrounding an endless bar or annular core, and supported upon a
stationary frame, and connected with one or more operative circuits, in combi-
nation with contact makers and brushes electrically connected with the coils of
the field-magnets for conducting a current from an outside source to excite the
field magnets.
Fifth-In combination with the described systems of rotating field-magnets and
stationary armature coils, an annular armature core so supported or suspended as
to be free to rotate, and having formed upon its faces transverse polar prominences
as, and for the purpose, set forth.
Sixth-In combination with parallel systems of rotating field magnets, and

page_text: with stationary armature coils, the floating armature core L, supported upon, and
centralized by, the internally placed friction rollers journalled in the stationary
armature frame, suitably connected to, and held in position by, the front
standard A' of the machine as, and for the purpose, set forth.
Seventh-The stationary armature coils G affixed to the rings H, h of the
stationary armature frame, secured to, or forming a part of, the central hub H³, as,
and for the purpose set forth :-
Eighth The field circuit wires O and 0¹ connected respectively with the
rotating parts of two contact makers connected with an outside circuit, for
supplying the current to charge the rotating field magnets.
Ninth In a dynamo-electric machine, a system of rotating field magnets and
a rotating armature core, stationary armature coils loosely surrounding the said
armature core, and a commutator in two parts which are electrically connected,
respectively, with the opposite ends of the circuit which includes the coils of the
field magnets, in combination with two commutator brushes which are electrically
connected, respectively, with the opposite ends of a circuit including any desired
number of the stationary armature coils for the purpose of exciting the field magnets
by a current derived from the said armature coils, and thus rendering the machine
self-charging.
Tenth In a dynamo-electric machine, in combination with suitably excited
field magnets, and an armature core, which are rotated, and armature coils which
are stationary, substantially as set forth, a commutator in two parts which are
electrically connected, respectively, with the opposite ends of a circuit including
any desired number of the said stationary armature coils, and two brushes
electrically connected, respectively, with the opposite ends of an outside or working
circuit.
Eleventh: In a dynamo-electric machine, the commutator M electrically connected
as set forth with the circuit which includes the coils of the rotating field magnets,
and with a circuit which includes any desired number of the stationary armature
coils G loosely surrounding the rotating armature core L, in combination with the
commutator R and contact wheels S, 8, electrically, connected by means of the
brushes S 8 with an outside circuit, and the brushes m* m³ electrically connected
with a circuit including those of the stationary coils G which are not employed to
charge the field.
In witness whereof I the said Henry Harris Lake have hereunto set my
hand and seal this Twelfth day of March in the year of our Lord One
thousand eight hundred and eighty three.