IMPROVEMENTS IN DYNAMO ELECTRIC MACHINES
Year: 1882

page_text: LETTERS PATENT to Henry Harris Lake, of the firm of Haseltine Lake
"
& Co, Patent Agents, Southampton Buildings, London, for an Invention of
"IMPROVEMENTS IN DYNAMO ELECTRIC MACHINES Communicated to him
from abroad by Silvanus Frederick Van Choate, of the City and State of New
York, United States of America, Electrical and Telegraphic Engineer.
PROVISIONAL SPECIFICATION left by the said Henry Harris Lake at the
Office of the Commissioners of Patents on the 28th August 1882.
"
HENRY HARRIS LAKE, of the firm of Haseltine, Lake, & Co, Patent Agents,
Southampton Buildings, London, " IMPROVEMENTS IN DYNAMO-ELECTRIC
MACHINES [A communication to him from abroad by Silvanus Frederick Van
Choate, of the City and State of New York, United States of America, Electrical
and Telegraphic Engineer.]
The object of this invention is to produce a dynamo-electric machine more
simple, compact, economical, efficient and durable, than other machines of like
nature as heretofore constructed. I accomplish this object by means of several
novel features hereinafter described and among which may be mentioned the
following, that is to say:-
A radical and peculiar construction and combination of the so called field-
magnets, as well as of the armature and armature-magnets.
A peculiar arrangement of the connections of the magnets and the commutator,
by means of which the field-magnets and the magnetic field-of-force in which the
armature and armature-magnets move, are maintained at a steady and uniform
maximum efficiency, not being changed or disturbed by any change in the so-
called external circuit or line, or in the electric currents existing or acting therein.
A peculiar construction, arrangement, and combination of the double compound
magnets, encompassing the armature and armature-coils, with peculiar polarities;
and the formation of unipolar and bipolar current machines.
A peculiar construction and division of the commutator by which the field-of-
force inagnets may be fed or maintained charged with unipolar currents; that is,
currents passing in one continuous direction, while the currents taken off and
FD0.71

page_text: '
passed through the exterior field or line, may be bipolar or alternating currents,
and vice versa; all the currents employed, both those for energizing the field-magnets
and those for supplying the external circuit or circuits being supplied from the
same armature.
An arrangement by which all the armature magnets or coils are kept continuously
in circuit.
A peculiar and novel arrangement of the so-called neutral line or points of the
double compound U-magnets, and the line of change of polarity of the armature.
The manner of constructing the armature in a series of segmental U magnets, and
so that its coils can be wound in a lathe, and also the manner of securing them to
the shaft
Heretofore, in dynamo machines having cylindrical or ring armatures, the so-
called neutral line has been commonly located, or made to produce its effects, that
is, change the polarity in the armature, on a line in the centre of the open space
and between the poles of the field-magnets, and the commutators have been con-
structed so as to successively cut out of circuit the helices or coils of the armature
for a longer or a shorter interval as they pass through this open space. In one
form of my invention, which I call the bipolar arrangement I have placed the
neutral line on a line which is at right angles to the aforesaid line; and, I keep
all the coils of the armature continually in circuit as they pass the first named
line. By this arrangement the polarity of the coils and the armature are changed
on a different line as compared with previous machines. The annular armature is
divided into two imaginary or bi-segmental armatures, one on the left, and the
other on the right hand side of the neutral line; the former constituting a bridge
or keeper across the two jaws of the double compound U-magnets on the left, and the
latter forining a bridge or keeper across the jaws on the right hand side. In this
arrangement there are three coils fully in the immediate magnetic field on either
side of the neutral line; while the other two coils are just on the neutral line of
my machine, and just about passing or changing from one polarity to the other;
the central coils on either side, being exactly in the open space between the jaws
of the U-magnets. In other ring or cylinder machines, while passing this space,
the coils or helices are thrown out of circuit by the commutators but in this
invention they are kept in circuit, since in the construction of a machine as herein
described, I find that the helices while passing through this space receive more
powerful inductive charges than they do at any other portion of the circle; the
magnetism emanating or flowing from one pole to the other of the double com-
pound magnets along the segmental armatures or keepers charge the coils
inductively with electricity, which is taken off by the brushes and commutators and
distributed as desired.
I will first describe the general construction of my improved machine and the
peculiar field-of-force poles, and then will proceed to point out the peculiarities in
the magnetic polarities of the field-of-force poles and the modifications that may be
made in charging the same and the peculiarities in the action of the field-of-force
poles upon the armature. I provide a top plate and a bed plate both being of iron and
which are directly secured together by four iron posts which are wound with coils of
wire and form the field-of-force magnets and from which plates project inwardly
towards one another, field-of-force pole pieces either formed in one piece with the
bottom and top plates, or suitably fastened thereto; said pole pieces being grooved
and curved to the circumference of the armature so as to each embrace the armature
for nearly half of its circumference and upon three of its sides. Said pole pieces
are bevelled or cut away at their sides to lighten the piece and to remove material
that would otherwise uselessly absorb magnetism.
The posts which form the cores for the field-of-force coils are provided with
-heads or flanges integral with them and also have projections at both ends which
extend slightly beyond the flanges and which enter perforations in the top and bed
plates, the heads or flanges at the same time resting flat against the plates so as to
give stability to the structure and to secure good magnetic contact; the field-magnets

page_text: are arranged in pairs and parallel to each other with their similar ends connected
together by means of two solid iron plates and the extension or elongations of the
said ends, by means of said plates, turn back inwardly and approximately near, and
also paralled with the sides of said magnets. These inwardly turned ends almost
meet at a central point along the sides of said magnets. The central portion of the
sides of the projecting pole plates are cut out on a radius from the centre of the
shaft of the machine, in a semi-circular form; while the same projections in a
longitudinal direction which is at right angles to the said shaft, are hollowed out in
such a manner as to form a deep U-shaped semi-circular groove tangential to the
centre of the shaft and in which groove the armature revolves in a direction parallel
with said magnets. The convolutions of the wire upon the magnets, besides directly
charging the cores, serve also to charge inductively the turned back projecting ends
or poles by reason of the proximity of said poles to said coils or convolutions;
terminal pole pieces, the magnets and the armature all being arranged parallel to
each other.
the
Any desired number of magnets may be employed at each end of the machine for
polarizing the pole-pieces; I employ four magnets, two at each side, for the sake of
simplicity and economy
The shaft of the machine is journalled in two upright posts of iron which are
seated on the bed plate, being secured thereto by bolts or screws passing through
flanges in the bottom of the posts and through perforations in the bed-plate.
Instead of allowing said posts to rest directly upon the iron base-plate as is
ordinarily done, I separate them from it by a plate of brass or other non-magnetic
material which prevents the dissipation of the magnetism in the plates into the
posts and shaft of the machine and also prevents any disturbance of the proper
polarities of the field-of-force magnets. The bolts or screws which secure the posts
to the bed-plate are also of some non-magnetic material, as for instance, gun metal.
The above construction is cheap and at the same time avoids the defects and
disturbances referred to. It is to be observed however that the posts might
be made entirely of non-magnetic material, but this would ordinarily be more
expensive.
The segmental sectional armature is constructed in the following manner, that is
to say, I provide a hub of some non-magnetic material suitably secured to the shaft,
into which are screwed a number of spokes, which spokes are fixed in place and
prevented from turning by dowel pins, or by set-screws passing through the sides
of the hub, which spokes are screw-threaded at their outer ends for the reception of
nuts. Each segmental section of the armature is constructed with a middle portion,
upon which an armature coil is wound between two heads or flanges in the ends of
which are formed counter-sunk grooves, the counter-sink in each extending to a
point which is the geometrical centre of the core. The angles serve for the bearing
points upon which the section turns when it is mounted in a lathe for the purpose
of winding a coil upon it.
The lower side of the flange has a straight transverse edge which sets flat upon a
flat bearing surface extending straight across the hub. The bearing face of the
flange which rests upon the hub is slightly curved in the direction of the axis of
the section to fit the curved circumference of the hub. A groove in the end of the
section in conjunction with the similar groove in the abutting end of the next
section forms a seat for a spoke, and two adjoining sections abut against one
another, the counter-sunk portion receiving the nut which engages with the end of
the spoke and serves to hold the structure together. The outer periphery and the
two sides of each flange or head are cut away transversely in order to lighten the
structure and to aid in the formation of poles at the junctions of two abutting
sections and to increase the magnetic power at those points. By this arrangement
the abutting flanges have together the form of a horse-shoe maguet, the two legs of
which are perceptibly separate, thus increasing the mutual magnetic action or
attractive effects between the armature and the faces of the field-of-force poles.
The grooves or recesses formed may be either rounded or square at the bottom.

page_text: The field of force coils upon the connecting posts may be wound or connected in
various ways. The first method of winding or connecting results in the formation
of a machine which I term a bipolar current machine and it consists in giving to the
coils a uniform winding or connecting them uniformly in such a way that all four
posts will tend to give to the top plate the same polarity, as for instance, south ;
and to the bottom plate the opposite polarity or north. One pole-piece will then
have a south polarity and the other pole piece a north polarity.
If but two coils are employed diametrically opposite one another their inner ends
are connected together and their free ends are connected to the segmental strips of a
commutator, the two halves of which are separated by diagonal slots-Commutator-
brushes bear upon said ring in the ordinary way at diametrically opposite points,
but are applied on the line joining the centre of the field-of-force poles instead of
upon the line passing between said pole-pieces. Another set of armature coils
displaced from the other set, preferably by an angle of 45°, are connected to one
another and to another divided commutator ring in a similar way to the first set.
The dividing slots of the latter ring are correspondingly displaced and are in a line
at right angles to the line occupied by the slots of the other ring.
The commutator-brushes of the two rings are properly connected so that the
current from both sets of bobbins is taken in multiple arc or parallel circuit and is
carried through all the field-of-force coils in series.
The current for the working circuit is taken in a similar way from other coils
upon the same revolving armature by adding proper commutator rings and brushes
to which said other coils are connected.
By properly connecting the commutator brushes in well known ways the currents
may be taken off for quantity or for tension.
In this commutator no break of current takes place at the dividing point between
the halves of the commutator ring and none of the bobbins are cut out of circuit at
any part of their revolutions. The slot is simply for the purpose of allowing for a
change of polarity in the arinature bobbins and is made diagonal or zig zag for
preventing any break in the circuit as the brush passes from one segment or half of
the commutator to the other.
Two contiguous bobbins on the same side of a diametrical line through the
armature are connected in multiple are with two bobbins on the diametrically
opposite side of the armature. The free ends of the two connected bobbins are
joined together at a point and thence taken to the balves of a commutator ring
thus giving a quantity current and saving a multiplication of the rings.
It is obvious that a larger number of bobbins on the same side of the armature
might be connected in multiple arc with a corresponding number on the opposite
side.
The number, however, that can be in practice so connected will depend upon the
whole number of bobbins in the armature. The remaining bobbins of the armature
may be similarly connected in multiple arc, and in sets, to other commutator rings.
The modified method of winding the field-of-force coils which results in the
production of what I call a unipolar current machine is as follows:-
The two field coils at one end of the machine, as for instance the two placed
at the right hand side of the bottom and top plates are so wound, and connected
as to induce an opposite polarity in the top plate from that induced in the same
plate by the coils at the other end.
The result of this is the production in the two ends of each pole piece of opposite
polarities.
In order to facilitate the production of poles at these points, and to prevent the
north magnetism, for instance, produced in one corner of the top or the bed plate
from merging with the south magnetism produced in the other end in a direct line
through the plate, I cut both sides of the top plate away thus forcing the polarity
into one pole-piece, while in a similar way both sides of the bed plate are cut
away, a flap being left for the posts supporting the shaft; a slot preventing the
merging of the magnetism and forcing it into the pole pieces.

page_text: The circulation of the magnetic currents in the field-magnets and armature in
this case takes place in certain paths, and the circulation in the armature under
the action of the field-pole-pieces is continuously in the same direction, whereas
under the first arrangement, or in what I term the bipolar current machine the
circulation of magnetism is in opposite directions in the two halves of the armature.
The magnetic lines of force passing from the pole pieces to the armature coincide
with one another in said armature; the north magnetism enveloping one side of the
ring passes into and through the same to the portion of said armature embraced
by south magnetism where it leaves the armature and passes into the field pole.
In the bipolar current machine the armature acts as a keeper for the pole-pieces
between but two pairs of opposite poles.
Thus the half of the armature on each side of the vertical line acts as a keeper
to the two halves of the field poles.
In the unipolar arrangement the armature resolves itself into theoretically four
keepers; one of which bridges the right hand poles N.S; the next the two upper
poles S.N; the next the two left hand poles N.S; and the fourth the two lower
poles S.N; and in every one of the quadrants it bridges two unlike poles.
According to one arrangement it can join unlike poles at but two portions of
its circumference; in the other portions it connects the pole pieces or points of
the same sign; so that there can be no continuous circulation of magnetic lines of
force through it owing to the opposition which occurs when two poles of the
same sign act upon an armature between them.
When the field coils are wound in the manner above described so as to produce
in the armature a continuous flow of magnetic lines of force in the same direction.
I find that I may obtain from the coils of said armature currents of electricity of
constant polarities at all points of the revolution of its bobbins; and I am thus
enabled to dispense with the commutating arrangements ordinarily employed
and to collect unipolar currents, that is, currents flowing in one direction, by
means of continuous rings secured to the shaft and connected with the armature
coils, upon which rings bear ordinary collecting brushes; or by means of any
similar continuous connecting devices.
Two continuous metallic rings are provided revolving with the armature, one
connected to one end, and the other to the other end of a set of armature-coils
taken in any order on the armature and connected to one another in series, or for
tension, or joined for quantity effects, in a well known way. Upon said rings bear
collecting brushes one for each ring and from which are taken the connections to
the field-of-force coils.
At one point the current from a brush divides a portion passing through field
coils at one end of the machine and the other through the coils reversely wound.
At another point connected to the other collecting brush the electric currents
passing through the coils unite.
There is another set of armature-coils taken in any desired order upon the same
arwature and connected for tension effects or in multiple arc; or for quantity as
may be desired; the free ends of which coils are connected to continuous rings or
bands moving with the armature and upon which rings or bands rest collecting
brushes which supply current to the external or working circuit-Both sets of
coils viz, those supplying the current to energize the field and those supplying the
current to the external or working circuit or circuits are upon the same armature;
but one set of coils are electrically entirely independent of the other coils and the
working circuit; so that no variations of resistance or change of condition in the
latter circuit can by any possibility change the intensity of the current circulating
through the field-of-force coils; or can in any manner affect the intensity of the
magnetic field; and the maximum intensity of said field once attained is never
changed excepting by a change of speed in the machine. No intermittent impulses
are interchanged from one circuit to the other; that is to say; the current generated
in the set of coils for one circuit is never transferred to the coils supplying the
other circuit,

page_text: I also provide an arrangement similar in all respects to that just described with
the exception that the current which circulates through the field magnet coils
passes through them in series, the coils being properly connected to one another
so that the current will circulate in opposite directions in the coils at opposite ends
of the machine The currents generated in the bipolar current machine are to be
utilized in the same way as those generated in the unipolar machine, viz a
portion of the coils on the armature supply current solely to the field coils, while
the remaining coils on the same armature, which coils are connected to an inde-
pendent commutator-supply current to the external or working circuit solely. In
this case also the independence and constancy of the magnetic field, irrespective of
variations in the working circuit, is secured; all the currents used being at the same
time supplied from the same armature.
I also provide an arrangement whereby the exterior or working circuit may be
fed with reverse or alternating currents supplied from either the unipolar current
or bipolar current machine, the currents being supplied from bobbins on the same
armature with those which serve to energize the field-of-force magnets.
The working circuit bobbins are supposed to be in a bipolar current machine,
the terminals of which bobbins are taken to a commutator. The continuous current
from the commutator brushes is taken by connections to the two sides of an
intermittent and current reversing commutator the two brushes of which bear
upon the two halves thereof in such a way that they are alternately and
intermittently connected to opposite sides of the commutator, so that intermittent
and reverse or alternating currents are produced in the external or working circuit.
The duration and time of each alternating or reversed impulse in the exterior
circuit is governed by the width of the dental projections on two bands and is
entirely independent of the time and duration or incidence of the currents generated
and circulating in the revolving armature coils.
It is obvious that this arrangement might be applied to the unipolar current
machine, and the arrangement of collectors herein described.
I also provide a novel mechanical construction for bringing the electrical
connections from the armature coils through the shaft and to the commutator
located outside of the bearings of said shaft.
The shaft is made hollow at its bearing portion and a cylindrical core of
insulating material is fixed in the interior of the shaft and centered by means of
washers. Bars of conducting material fixed upon the face of the insulating cylinder
or placed in grooves in the same serve to convey the currents from the armature
coils to the commutator rings; connection between said bars and the armature
coils being made by screw bolts which pass through insulating washers and screw
into the ends of the bars; the free ends of the armature coils being connected to
screw-cups formed on the outer ends of the bolts. The space between the bars and
the outer shell of the shaft and also the cavity in one part allow the circulation of
air and tend to keep the parts cool.
The commutator rings, bars, or segments are secured to an insulating cylinder
which is mounted upon a metal tube firmly fixed in the end of the hollow shaft
by dowels or screws or other means, so that said tube, with the attached cylinder
and the commutator-rings, may be detached from the shaft at pleasure.
Connection between the rings and the central bars is made by auxiliary bars or
strips mounted upon an insulating sleeve or cylinder, which strips are metallically
connected at one end by screws to projecting strips extending from the several
rings and the strips, and at the other end by screw-bolts which screw into the ends
of the central connecting bars.
It is obvious that I might employ a field-magnet having bars or rods on one side
only of the pole pieces instead of on both sides. In such case I might use one
field-magnet only instead of two Such forms would however be less powerful.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Henry Harris Lake in the Great Seal Patent Office on the
28th February 1883.
HENRY HARRIS LAKE, of the firm of Haseltine, Lake and Co., Patent Agents,
Southampton Buildings, London, "IMPROVEMENTS IN DYNAMO-ELECTRIC
MACHINES" A communication to me from abroad by Silvanus Frederick Van
Choate, of the City and State of New York, United States of America, Electrical
and Telegraphic Engineer
The object of this invention is to produce a dynamo-electric machine which will
be more simple, compact, economical, efficient and durable than machines of like
nature as heretofore constructed. I accomplish this object in the manner herein-
after set forth, and the said invention comprises various novel features, among
which may be mentioned the following, that is to say:-A peculiar construction
and combination of the so-called field magnets, as well as of the armature and
armature magnets. A peculiar arrangement of the connections of the magnet coils
and the commutator whereby the field-magnets, and the magnetic field-of-force in
which the armature moves, are maintained at a steady and uniform maximum
efficiency not being changed or disturbed by any change in the so-called external
circuit or line, or in the electric currents existing or acting therein. A peculiar
construction, arrangement and combination of double compound U-shaped magnets,
encompassing the armature and armature coils with peculiar polarities; and the
formation of unipolar and bipolar current machines. A peculiar construction and
division of the commutator whereby the field-of-force magnets may be supplied, or
maintained charged, with unipolar currents, that is to say, currents passing in one
direction continuously, while the currents taken off and passed through the
exterior circuit or line, may be bipolar or alternating currents, and vice versa; all
the currents employed, both those for exciting the field magnets and those for
supplying the external circuit or circuits, being supplied from the same armature.
An arrangement whereby all the armature magnets or coils are kept continuously
in circuit. A peculiar and novel arrangement of the so-called neutral line or
points of the double compound U-shaped magnets, and the line of change of
polarity of the armature. Also a novel mode of constructing the armature with a
series of segmental U-shaped magnets so that its coils can be wound in a lathe, and
an improved mode of securing the segments of the said armature to the shaft.
In the accompanying drawings,
Figure 1 is a sectional elevation of the improved machine, the field magnet coils
being shown by dotted lines.
Figure 2 represents a vertical transverse section of the double compound
U-shaped pole-pieces or polar extensions of the field-magnets of the machine,
showing also a side elevation of the armature.
Figure 3 is a side view, half in section and half in elevation, of a pole-piece
of the improved field-magnet and the end-plate or bed-plate of which it forms
a part.
Figure 4 is an end view of the same, half in section and half in elevation.
Figure 5 is a plan or top view of the bed-plate with the pole-piece of the field
magnet projecting therefrom.
Figures 6, 7, 8, 9 and 10 represent details of construction of the segmental
armature.
Figures 11, 12, 13, 14, 15, 16 and 17 are diagrams illustrative of the magnetic
polarities of the field-of-force magnets; and of the armature when combined with
field magnets having the peculiar polarities and construction herein described.

page_text: Figures 18, 19, 20, 21 and 24 are diagrams illustrating the connections and
circuits of the machine.
Figure 22 is a central longitudinal section, showing the construction of the
commutator.
Figure 23 is a section on the line x, x Figure 22.
In dynamo-electric machines having cylindrical or ring armatures, as heretofore
constructed, the so-called neutral line is commonly located, or made to produce its
effect (that is to say, change the polarity in the armature) on a line in, or near, the
centre of the open space between the poles of the field magnets, as indicated by
the dotted line C, C, Figure 11; and the commutator is constructed so as to
successively cut out of circuit the helices or coils of the armature, for a longer or
shorter interval, as they pass through this open space. According to one part of
the said invention, which I call the bipolar arrangement, I place the neutral line,
as indicated by the dotted line A. A at right angles to the line C, C; and I keep
all the coils of the armature continually in circuit as they pass the line C, C. By
this arrangement, the polarity of the coils and of the armature is changed on the
line A A instead of on the line C, C, as in the machines heretofore employed.
Figure 11 illustrates the principles and arrangement of the polarities and armatures
of machines constructed in accordance with this part of my Invention.
The positive poles of the double compound U-shaped magnets of the field of
force are indicated by the letters N, N, and the negative poles by the letters S, S.
The annular armature is divided into two imaginary bi-segmental armatures, or
keepers, as indicated by the letters N and S on the left, and S and N on the right
hand side of the line A, A, the former constituting a bridge or keeper across the
two jaws of the double compound U-shaped magnets on the left, and the latter
forming a bridge or keeper across the jaws on the right hand side. It will be
observed that, in this arrangement, there are three coils a fully within the
immediate magnetic field on either side of the line A, A; while the other two
coils a are just on the neutral line of the machine, and just about passing or
changing from one polarity to the other; the central coils on either side being
exactly in the open space between the jaws of the U-shaped magnets. In other
machines having cylindrical or ring armatures, the coils or helices, while passing
through this space, are cut out of circuit by the commutators, but, in the present
Invention, they are kept in circuit, and, in machines constructed as herein described,
the helices, while passing through this space, receive more powerful inductive charges
than they do at any other portion of the circle; the magnetism emanating or
flowing from one pole to the other of the double compound U-shaped magnets
along the segmental armatures or keepers charges the coils inductively with
electricity, which is taken off by the brushes and commutators and distributed in
any suitable manner according to the purpose for which it is required.
I will first describe the general construction of the machine and the peculiar
field-of-force poles, and will then proceed, by the aid of the diagrams, to point out
the peculiarities in the magnetic polarities of the field-of-force poles, and the
modifications that may be made in charging the same, and the peculiarities in the
action of the field-of-force poles upon the armature.
Referring to Figures 1, and 2, B represents the top plate and B' the bed-plate of
the machine, which plates are of iron and are directly connected and secured by four
iron posts or bars D. These iron bars are wound with coils of wire and form the
field-of-force magnets, and form the said plates the pole pieces E, E' project towards
one another, being either formed in one piece with the bottom and top plates
respectively, or suitably fastened thereto; the said pole-pieces are made with a
semi-circular groove, in the manner shown in Figures 3 and 4, so that each piece will
enclose nearly half of the armature. These pole-pieces are bevelled or cut away at
their sides, as shown at m, Figure 4, to reduce their weight and to remove material
that would otherwise uselessly absorb magnetism.
The position of the iron posts or bars D is clearly indicated in Figures 1 and 2,
the countersunk holes, in which the said posts are fixed, being at the four corners of

page_text: the bed-plate as indicated at f, f, Figure 5. The coils of wire encircling the said
posts fill the spaces e, e, within the dotted lines, Figure 1, while the bolts which
fasten the plates B, B' and posts D together are shown at g. The posts D, which
form the cores for the field-of-force coils, are provided with heads or Blanges k, k,
integral with them, and also have a projection at each end which extends slightly
beyond one of the said flanges and enters a recess in the top-plate or bed plate,
the said heads or flanges resting against the plates so as to give stability to the
structure and secure good magnetic contact.
It will be observed that, in the present invention, the field-magnets D are
arranged in pairs and parallel to each other with their similar ends connected by
means of the two solid iron plates B, B'; and the extensions or pole-pieces E, E¹ turn
inwardly approximate to, and parallel with, the sides of the said magnets. These
inwardly turned extensions almost meet on a central line along the sides of the said
magnets. The sides of the projecting pole-pieces are cut out concentrically with
the shaft of the machine, so as to form, in each of them, a semi-circular space or
groove extending in a direction at right angles to the said shaft. In this groove
the armature revolves in a plane parallel to the said magnets. The coils or
convolutions of the wire upon the magnets, besides directly charging the cores,
serve also to charge the turned back projecting ends or pole-pieces by reason of the
proximity of the said pole-pieces to the said coils or convolutions; the terminal
pole-pieces, the magnets and the armature all being arranged parallel to each
other.
Any desired number of magnets D may be employed at each end of the machine
for polarizing the pole-pieces, I employ four magnets, two at each side, for the
sake of simplicity and economy.
F represents the shaft of the machine journalled in two iron standards h, which
are seated on the bed-plate B₁ and secured thereto by bolts or screws passing
through flanges in the bottom of the standards, and through holes h³ (Figure 5) in
the bed-plate. Instead of placing the said standards directly upon, or in contact
with; the iron bed-plate, as is ordinarily done, I separate them from it by a plate of
brass, or other non-magnetic material, which prevents the dissipation of the
magnetism in the plates through the standards and shaft of the machine, and also
prevents any disturbance of the polarities of the field-of-force magnets. The bolts
or screws which secure the said standards to the bed-plate are also made of some
non-magnetic material, such as gun-metal. The above described construction is
cheap and, moreover, it obviates the defects and disturbances above referred to. It
is to be observed, however, that the standards might, if desired, be made entirely of
non-magnetic material, but this would ordinarily be very expensive.
The segmental sectional armature is constructed in the following manner, that is
to say-K (Figure 2) represents a hub of some non-magnetic material suitably
secured to the shaft, into which hub are screwed a number of spokes n fixed in
place, and prevented from turning, by dowels, pins or set-screws 2, passing through
the sides of the hub. These spokes are screw-threaded at their outer ends for the
reception of nuts p. Each seginental section of the armature is constructed, in the
manner shown in Figures 6, 7, 8, 9 and 10, with a middle portion r, upon which an
armature-coil is wound between the two heads or flanges s, in the ends of which
are formed counter-sunk grooves t, the counter-sink in each groove extending to a
point which is the geometrical centre of the core or middle portion ; the
angles at w serve for the bearing points upon which the section turns when it is
mounted in a lathe for the purpose of winding a coil upon it.
Figure 7 shows an end elevation of one section, and Figure 8 a transverse
section through the portion . The lower side of the flange s is shown with a
straight transverse edge which fits upon a bearing surface extending straight across
the hub. The bearing face of the flange which rests upon the hub is slightly
curved in the direction of the axis of the section to fit the circumference of the
hub. The groove t in the end of one section, in conjunction with the similar
groove in the abutting end of the next section, forms a seat for a spoke n, as may

page_text: be seen in Figure 9, where two adjoining sections are shown abutting against one
another, the counter-sunk portion receiving the nut which engages with the end of
the spoke and serves to hold the structure together. By removing two of the said
nuts, one of the magnets can be removed from the armature for repairs or for
winding the coils. This construction is shewn more clearly by the dotted lines in
Figure 2, indicating the outline of the grooves and the spokes. As shown in
Figures 6, 9, and 10, the outer periphery and the two sides of each flange or head
are cut away transversely, in order to reduce the weight and to aid in the formation
of poles at the junctions of two abutting sections and increase the magnetic power
at these points.
By this arrangement, as can be readily seen, the abutting flanges have together
the form of a horse-shoe magnet the two limbs of which are perceptibly separate,
thus increasing the mutual magnetic action or attractive effects between the
armature and the faces of the field-of-force poles. The grooves or recesses formed
may be either rounded or square at the bottom. In Figure 2, the grooves are
shewn as formed only on the periphery of the armature, the grooves on the sides
being omitted to prevent confusion. An armature built up of such sections, with
the polarities N, S, which the construction above described tends to produce at the
points of junction, is shewn in Figure 12 the coils being indicated by the zig-zag
heavy lines.
The field-of-force coils upon the connecting posts or bars D may be wound or
connected in various manners. The first method of winding or connecting results
in the formation of a machine, which I term a "bipolar current machine," and the
said method consists in uniformly winding the coils, or connecting them in such a
manner that all the said posts or bars will tend to give to the top-plate the same
polarity, south for instance; and to the bottom plate the opposite polarity, or
north. The pole-piece E will then have a south polarity and the pole-piece E¹ a
north polarity.
The connections of the field-of-force coils on the posts or bars D with the
armature-coils is illustrated by the diagrams Figures 20 and 21.
One set of armature coils is indicated by the figures 7, 7, all the said coils on
one side of the vertical line being supposed to be diametrically opposite those upon
the other side thereof.
If only two coils are employed, diametrically opposite one another, their inner
ends are joined, and their free ends are connected to the segmental strips of a
commutator or ring indicated at 9, the two halves of which are separated by
diagonal slots. Commutator brushes bear upon the said ring in the ordinary
manner at diametrically opposite points, but are applied on the line passing through
the centre of the field-of-force pole-pieces, instead of upon the line passing between
the said pole-pieces. Another set of armature coils, placed preferably at an angle
of forty-five degrees with the set 7, 7, is indicated at 8, 8. These coils are connected
to one another and to a divided commutator or ring 10 in a similar manner to the
set 7. The dividing slots of the latter ring are correspondingly placed and are on
a line at right angles to the line occupied by the slots of the ring 9. The commu-
tator brushes of the two rings are properly connected, as indicated at 12, so that
the current from both sets of bobbins is taken off in multiple arc or parallel circuit
and is carried through all the field-of-force coils 11 in series. The arrows indicate
the direction of the currents. The current for the working circuit is taken off in
a similar manner from other coils upon the same revolving armature, by adding
proper commutator rings and brushes, to which the said coils are connected. By
properly connecting the commutator brushes in any well known manner, the
currents may be taken off for quantity or for tension.
In the commutator, no interruption of the current takes place at the dividing
point between the halves of the commutator ring, and none of the bobbins are cut
out of circuit at any part of their revolution. The slot is simply for the purpose
of allowing for a change of polarity in the armature bobbins, and is made diagonal

page_text: or zig-zag, as indicated in Figures 20 and 21, to prevent any break in the circuit as
the brush passes from one segment or half of the commutator to the other.
The diagram Figure 21 illustrates an arrangement of the connections in which
two contiguous bobbins, on the same side of a diametrical line through the
armature, are connected, in multiple arc, with two bobbins on the diametrically
opposite side of the armature. The free ends of the two connected bobbins are
joined at the point 14, Figure 21 (represented as a screw-connection or binding
screw in Figure 22) and thence taken to the halves of a commutator ring, thus
giving a quantity current and saving a multiplication of the rings.
It is obvious that a larger number of bobbins on the same side of the armature
might be connected in multiple arc with a corresponding number on the opposite side.
The number, however, that can, in practice, be so connected will depend upon
the whole number of bobbins in the armature. The remaining bobbins of the
armature may be similarly connected in multiple arc and in sets to other
commutator rings.
The modified method of winding the field-of-force coils, which results in the
production of what I call a "unipolar current machine," is as follows, that is to
say-The two field coils at one end of the machine, for instance the two placed
at the right hand side of the bottom and top plates, Figures 2 and 5, are so
wound and connected as to induce an opposite polarity in the top plate from that
induced in the same plate by the coils at the other end of the said machine. The
result of this arrangement is the production, in the two ends of each pole-piece, of
opposite polarities, as indicated by the letters N, S, Figures 14, 15 and 17. In
order to facilitate the production of poles at these points and to prevent the north
magnetisın, for instance, produced in one corner of the top plate or the bed-plate,
from merging with the south magnetism produced in the other end, in a direct line
through the plate, I cut away both sides of the top-plate, as shown by the dotted
lines 16, Figure 5, thus causing the magnetism to enter the pole-piece E; while, in
a similar manner, both sides of the bed-plate are cut away, as shown by the
dotted lines 15, a flange being left for the standards supporting the shaft; the slot
indicated at 17 prevents the merging of the magnetism and compels it to enter the
pole-pieces.
The circulation of the magnetic currents in the field magnets and armature takes
place in the paths indicated by the arrows in Figure 15, and, as will be observed,
the circulation in the armature, under the action of the field pole-pieces, is
continuously in the same direction, whereas, in Figure 16, which is a diagram
illustrating the circulation of the magnetism under the first arrangement, or in
what I term the bipolar current machine, the circulation of magnetism is in
opposite directions in the two halves of the armature, as indicated by the arrows.
Figures 13 and 14 illustrate the manner in which the magnetic lines-of-force
passing from the pole-pieces to the armature coincide with one another in the said
armature. Figure 14 is a side view of the armature and Figure 13 is an edge view
of the same.
It will be seen that the north magnetism enveloping one side of the ring passes
into and through the same to the portion of the said armature embraced by south
magnetism, where it leaves the armature and passes into the field pole.
In Figure 11, which illustrates the magnetic polarity of the bipolar current
machine, it will be observed that the armature acts as a keeper for the pole-pieces
between only two pairs of opposite poles. Thus, the half of the armature on each
side of the vertical line acts as a keeper to the two halves of the field poles.
In the arrangement illustrated in Figure 17, vis: the unipolar arrangement, the
armature resolves itself into (theoretically) four keepers; one of which bridges
the right hand poles N, S; the next the two upper poles S, N; the third the two
left band poles N,S; and the fourth, the two lower poles SN; and, in every one
of the quadrants, it bridges two unlike poles.
In Figure 11, however, it can join unlike poles at only two portions of its
circumference ; in the other portions it connects the pole pieces or points of the

page_text: same sign; so that there can be no continuous circulation of magnetic lines-of-
force through it, owing to the opposition which occurs when two poles of the same
sign act upon an armature between them.
When the field coils are wound, in the manner above described, so as to produce
in the armature a continuous flow of magnetic lines-of-force in the same direction,
as indicated in Figures 14 and 15, I find that I may obtain from the coils of the
said armature, currents of electricity of constant polarities at all points of the
revolution of its bobbins; and I am thus enabled to dispense with the commutating
arrangements ordinarily employed, and to collect unipolar currents, that is to say,
currents flowing in one direction, by means of continuous rings secured to the shaft
and connected with the armature coils, upon which rings bear ordinary collecting
brushes; or by means of any similar continuous connecting devices. Figures 18
and 19 are diagrams illustrating connections of the armature bobbins, the collectors,
and the field-of-force coils that may be employed. In Figure 18 the field coils
are supplied in multiple arc or in parallel circuit, and, in Figure 19, in series or in
tension.
Referring to Figure 18, two continuous metallic rings are indicated at 19, which
revolve with the armature, one connected to one end and the other to the other
end of a set of armature-coils M, which may be taken in any order on the armature
and may be connected to one another in series or for tension, or joined for quantity
effects in any well known manner. Upon the said rings bear the collecting
brushes 20, one for each ring, from which brushes are taken the connections to the
field-of-force coils R, R¹.
At the point 21, the current from the brush 20 divides, a portion thereof passing
through the field coils R at one end of the machine, and the remainder through
the coils R' which are reversely wound.
At the point 22, which is connected to the other collecting brush, the electric
currents passing through the coils unite, the said currents passing in the direction
of the arrows. N indicates another set of armature-coils, which may be taken in
any desired order upon the same armature, and may be connected for tension
effects, or in multiple arc or for quantity, as may be desired; the free ends of these
coils are connected to continuous rings or bands 23, which move with the armature
and upon which rest collecting brushes which supply the current to the external or
working circuit. Both sets of coils M, N, that is to say, those supplying the current
to excite the field magnets and those supplying the current to the external or
working circuit or circuits, are upon the same armature; but the coils M, are,
electrically, entirely independent of the coils N and the working circuit; so that
no variations of resistance or change of condition in the latter circuit, can change
the intensity of the current circulating through the field-of-force coils; or can, in
any manner, affect the intensity of the magnetic field; and the maximum intensity
of the said field being once attained, is never changed, excepting by a change of
speed in the machine. No intermittent impulses are interchanged from one circuit
to the other, that is to say, the current generated in the set of coils for one circuit
is never transferred to the coils supplying the other circuit
Figure 19 shows an arrangement similar to that shown in Figure 18, with the
exception that the current which circulates through the field-nagnet-coils passes
through them in series, the coils being properly connected to one another, as indi-
cated, so that the current will circulate in opposite directions in the coils at opposite
ends of the machine. The currents generated in the bipolar current machine
whose circuits are indicated in Figures 20 and 21 are utilized in the same manner
as those generated in the unipolar machine, that is to say, some of the coils on the
armature supply current solely to the feild coils, while the remaining coils on the
same armature (which coils are connected to an independent commutator) supply
current to the external or working circuit only. In this case also the independence
and constancy of the magnetic field, irrespective of variations in the working
circuit, is ensured; all the currents used being, at the same time, supplied from the
same armature,

page_text: Figure 24 illustrates an arrangement whereby the exterior or working circuit
may be supplied with reverse or alternating currents from either the unipolar
current, or the bipolar current machine, the currents being supplied from bobbins
on the same armature with those which serve to excite the field-of-force magnets.
In the diagram, for the sake of clearness, the latter bobbins are not shown. The
working circuit bobbins are supposed to be in a bipolar current machine and their
terminals are connected to a commutator of the kind indicated in Figures 20 or 21.
The continuous current from the commutator brushes is taken by connections to
the two sides of an intermittent and current-reversing commutator 52, the two
brushes of which, indicated at 53 bear upon the two halves thereof in such a
manner that they are alternately and intermittently connected to opposite sides of
the commutator, so that intermittent and reverse or alternating currents are
produced in the external or working circuit 54. The duration and time of each
alternating or reversed impulse in the exterior circuit 54, are governed by the
width of projections on two bands and are entirely independent of the time and
duration or incidence of the currents generated and circulating in the revolving
armature coils.
It is obvious that this arrangement might be applied to the unipolar current
machine with the arrangement of collectors illustrated in Figure 18.
In Figures 22 and 23, is illustrated a novel mechanical device for bringing the
electrical connections from the armature coils through the shaft and to the
commutator located outside the bearings of the said shaft.
Figure 22, is a longitudinal section of the commutator and shaft, and Figure 23
is a transverse section on the line x, x Figure 22. F indicates the shaft which is
made hollow at its bearing portion or journal 25. A cylindrical core of insulating
material 26 is fixed in the interior of the shaft F, and held concentric therewith by
means of washers 28. Bars of conducting material 27 are fixed upon the face of
the insulating cylinder, or placed in grooves in the same, and serve to convey the
currents from the armature coils to the commutator rings; connection is made
between the said bars and the armature coils by screw bolts 14 which pass through
insulating washers and screw into the ends of the bars; the free ends of the
armature coils being connected to binding-screws in the outer ends of the bolts.
The space between the bars and the outer shell of the shaft, and also the cavity
in the part 26, permit the circulation of air and thus tend to keep the parts cool.
The commutator rings, bars, or segments 40, are secured to an insulating cylinder
41, which is mounted upon a metal tube 42, firmly fixed in the end of the hollow
shaft F, by pins, screws or other suitable means, so that the said tube, with the
attached cylinder 41 and the commutator rings 40, may be detached from the
shaft at will. Connection is made between the rings 40 and the central bars 27 by
auxiliary bars or strips 43 mounted upon an insulating sleeve or cylinder 45. The
strips 43 are electrically connected at one end, by screws 46, to projecting strips
extending from the several rings, and at the other end by screw-bolts 47, which
screw into the ends of the central connecting bars 27.
It will be obvious, on referring to Figure 1, that I might employ a field magnet
having bars or rods on one side only of the pieces E, E', instead of on both sides.
In such case I might use one field magnet instead of two. Such forms would,
however, be less powerful than that shown.
Having thus fully described the said Invention as communicated to me by my
foreign Correspondent and the manner of performing the same I wish it understood
that I claim :—
First In a field magnet for a dynamo-electric machine, a bar or rod wound
with a magnetizing coil or helix and provided with pole-pieces projecting towards
one another, and having grooves or recesses curved and arranged in the line of
rotation of the armature and at right angles to the axis thereof so as to closely
embrace the said armature and present a solid polarized mass to its periphery and
its two sides.
Second-The combination, substantially as described, of parallel field-of-force

page_text: .
magnets, re-entering or returning grooved or recessed pole-pieces, projecting towards
one another and parallel to the said magnets, and embracing the periphery and two
sides of an armature revolving in the said groove parallel to the field magnets,
substantially as set forth.
Third A field magnet for a dynamo-electric machine, consisting of two or more
parallel cores directly connected at each end to a common intermediato pole-piece
projecting towards the pole-piece at the other end and in close proximity to the
field magnet coils, as, and for the purpose, described.
Fourth-The combination, with two or more magnets arranged parallel to each
other and having their poles or extremities bent inwardly between the said magnets
and approaching each other and also parallel with the sides of the said magnets, of
an armature revolving between the said poles and parallel both to the poles and to
the magnets, substantially as set forth.
Fifth The combination, substantially as described, of the iron top and bed-
plates having grooved pole-pieces integral therewith and projecting towards one
another, the said pole-pieces being curved to correspond with the circumference
of the armature revolving between them, and connecting bars or posts D,
wound as described to induce in the said pole-pieces the polarities above set
forth.
Sixth A top or bottom plate for a dynamo-electric machine made of iron
and provided with a projecting pole-piece integral with it and grooved and
curved in the manner described so as to embrace the armature, substantially as
above set forth.
Seventh-The combination, with the plate B forming a pole-piece, of a bar or
rod D wound with a magnetizing coil or helix and provided with a flange or
head of magnetic material resting in magnetic contact with the said plate, as, and
for the purpose, described.
Eighth The combination, with a number of magnets D, of common plates or
pole-pieces B or B₁ cut away at points between the magnets to compel the
magnetism to enter the said pole-pieces, substantially as, and for the purposes, set
forth.
Ninth The combination, with the armature of a dynamo-electric machine, of
independent commutators, or collectors, each connected to an independent set of
coils or helices on the same armature, one or more sets being arranged to excite or
energize the field-of-force magnet or magnets and the other set or sets to supply an
external or working circuit or circuits, each circuit being independent of the others,
as above set forth.
Tenth In a dynamo-electric machine, an armature whose coils or helices are
divided into two or more independent sets, each of which sets is connected to an
independent field magnet circuit or working circuit, and supplies the same
independently of the other set or sets, as above described.
Eleventh The combination of circuits, connections, commutators, or collectors,
and coils, in continuously closed circuit as above described, and as shown in
Figures 18 and 19, or in Figures 20 and 21, for the purposes set forth.
Twelfth The combination, with a series of armature bobbins or helices divided
into sets and revolving between two curved field-of-force poles, of commutator
rings so divided as not to break the connection with the brushes, and commutator
brushes applied to the said rings on the line joining the field-of-force poles, as, and
for the purposes, set forth.
Thirteenth In a dynamo-electric machine, the combination and arrangement of
the connections, commutator rings and brushes as described, whereby the field-of-
force magnets may be supplied with continuous currents, that is to say, currents
passing in one direction and generated in one set of coils on the armature, while
the exterior or working circuit is supplied with intermittent reversing or alternating
currents generated in another set of coils on the said armature.
Fourteenth In a dynamo electric machine, an armature having its bobbins
connected in two sets independent of one another, one set being connected to the

page_text: field-of-force coils solely and supplying a continuous current thereto, while the
other set is connected through commutators or collectors and reversing or
alternating devices, as described, solely with an exterior or working circuit.
Fifteenth In a dynamo-electric machine, an armature whose coils are arranged
in the manner above described so that all the said coils are kept continuously in
circuit, and the said circuit is kept continuously closed, as, and for the purpose, set
forth.
Sixteenth An armature section formed with a circular cylindrical central
portion and flanged heads, bevelled as shown, as, and for the purpose, set forth.
Seventeenth- In an annular armature, a U-shaped magnet formed as shown in
Figures 6, 7 and 8 with bevelled ends, for the purposes set forth.
Eighteenth An armature built up of segmental sections, each of which is
provided with heads grooved at their top and sides, as, and for the purpose,
described.
Nineteenth-In a dynamo electric machine, an annular armature built up of
segmental magnets as described, and connected and held together with spokes
secured by dowels or otherwise and by nuts, so that by removing two of the nuts
any one of the said magnets can be removed from the said armature for repairs or
for winding the coils, substantially as set forth.
Twentieth-In a dynamo-electric machine, an annular armature built up of
segmental magnets whose abutting or adjoining ends are cut away at the sides,
substantially as, and for the purposes, set forth.
Twenty first The combination, with the iron bed-plate forming a portion of the
field-of-forc magnet, of an armature shaft supported on the said plate, but
magnetically insulated therefrom, as, and for the purpose, set forth.
Twenty second-The combination, with the hollow armature-shaft, of an interior
supporting tube or rod of insulating material and conducting bars attached thereto,
all substantially as, and for the purpose, set forth.
Twenty third The combination of the insulating cylinder 41, commutator
-plates or segments thereon, and the supporting tube 42, detachably secured to the
end of the armature shaft, all substantially as, aud for the purposes, set forth.
In witness whereof I the said Henry Harris Lake have hereunto set my
hand and seal this Twenty eighth day of February in the year of our
Lord One thousand eight hundred and eighty three.
(L.S.)