Improvements in Dynamo Electric Machines.
Year: 1897

page_text: Date of Application, 5th Oct., 1337-Accepted, 4th Dec.,
1897
Improvements in Dynamo Electric Machines.
I, MILTON ELLSWORTH THOMPSON, of Ridgway, Elk County, Pennsylvania,
United States of America, Electrical Engineer, do hereby declare the nature of
this invention, and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
Fig. 1, is an elemental diagram illustrating principles of construction involved
in my improved machine as exemplified in a drum armature machine with interior
armature:
Fig. 2, an end view of the field frame, bushing ring and armature of a multi-
polar drum armature machine exemplifying my improvements, portions appear-
ing in vertical section in the planes of lines b and c of Fig. 3:
Fig. 3, a side view of the same, with the armature omitted, parts appearing in
vertical section in the plane of line a of Fig. 2:
Fig. 4, a perspective view of the bushing-ring, without its windings:
Fig. 5, a plan of the interior wall of a portion of the bushing-ring, portions of
this plan appearing in horizontal section in the plane of line c of Figs. 6 and 7,
the lower portion of this view illustrating the winding diagrammatically:
'
Fig. 6, à radial section of the bushing-ring, in the plane of line e of Fig. 5:
Fig. 7, a similar section of the bushing ring in the plane of line f of Fig. 5:
Fig. 8, a side elevation of the armature spider, shown half in diametrical
section in conjunction with its disks and bar windings:
Fig. 9, an end view of a portion of the armature, parts appearing in vertical
section in the plane of line of Fig. 8:
Fig. 10, an edge elevation of a pair of armature disks with their separating
blocks, the lower portion of this view presenting a section in the plane of line a
of Fig. 2:
Fig. 11, a plan of a portion of the armature, projected from Fig. 9, and illustrat-
ing the system of connections between the bars, forming the armature winding:
Fig. 12, an elevation of a portion of one of the field coils, with its cording, the
latter being partially broken away to exhibit one of the insulating studs:
Fig. 13, an inside view of a portion of the field-frame, showing one of the pole-
necks and its field-coil: and
Fig. 14, an end view of a commutator bar in connection with two of the winding
bars of the armature.
Before taking up details of the exemplifying construction I will explain the
principle upon which the construction is mainly based, employing Fig. 1 for this
purpose. The other figures of the drawings illustrate my invention in connection
with a machine of multi-polar type, but in explaining the principles involved it
has been thought best, for the sake of simplicity and clearness, to consider a
machine of the bi-polar type, as illustrated in Fig. 1. In this diagram, Fig. 1,
let it be understood that the dotted lines indicate conductors in the distance; that
conductors viewed endwise have their direction of current indicated by a cross
(representing the heel of the arrow) if the current goes from the observer, and by
a dot (representing the point of the arrow) if the current comes toward the observer.

page_text: In Fig. 1, the armature is elementally represented as being provided with sixteen
longitudinal conductors, which are to be assumed as being connected up as usual.
Referring to Fig. 1 of the drawings:-
1, indicates the armature, its usual winding being represented by the sixteen
longitudinal conductors with the currents flowing through them in the direction
indicated by the signs (crosses and dots), the uppermost and lowermost con-
ductors representing the conductors short-circuited by the brushes, the arrow on
the armature indicating its direction of motion, and the entire diagram treating
the machine as a generator:
2, the field-poles, having the polarity indicated by N. and S.
.
3, a circumferential series of fixed longitudinal conductors, carrying currents in
the directions indicated by the signs, these conductors being distributed symmetri-
cally around the armature and occupying a position radially exterior to the
armature and radially interior to the field-poles:
4, a pole, of S sign, presenting itself near the periphery of the armature and
angularly midway between the two field poles and in advance of the field pole
having opposite sign:
5, a similar pole of N sign disposed similarly in advance of the field pole of
opposite sign:
6, the mains, which lead to the work part of circuit:
7, the shunt circuit for the field-poles 2.
It will be observed that the field is in shunt; that the main circuit includes the
armature and the annular series of conductors 3; that those conductors of the
armature which have currents flowing in a given direction move in the field of
such of conductors of the series 3 as have currents moving in them in the opposite
direction; that current strength in the conductors of series 3 will vary with that
of the armature coils; that the short cirouited armature conductors move in the
fields of poles 4 and 5; and that the strength of poles 4 and 5 vary with the
armature current, since they are energized by the series of conductors 3.
As the armature conductors move in the magnetic field produced by series of
conductors 3 bearing magnetically opposing currents of equal strength, it is
obvious that armature reaction upon the field is completely neutralized and com-
pensated for. An armature coil upon being short circuited by the brushes, is
within and its current is reversed while it is within the fields of poles 4 and 5,
which fields vary in strength with the armature current; the current in the short
circuited coils being thus reversed and built up in strength before the coil again
passes into the armature circuit. Under this system there is no necessity for alter-
ing the position of the diameter of commutation, and there is a total avoidance of
sparking.
"
In practice I call the poles 4 and 5 commutation lugs": I arrange the con-
ductors of the series 3 as the longitudinal clements of coils; I mount the com-
mutation lugs and the coils forming the conductors 3 in a bushing-ring fitting
within the field-poles and surrounding the armature; I use less air gap than has
been before practicable, having considered it only from a mechanical standpoint,
being able to ignore it electrically; I provide the armature with conductors of
great radial depth of winding, being able to deal with a depth of copper hereto-
fore impracticable; and I produce a machine having about half the size of
machines of similar capacity as constructed on other approved systems.
The diagram shown in Fig. 1, relates to a generator. For a motor the direc-
tion of current is reversed for the same direction of armature rotation, and for
mechanical convenience I arrange that the bushing-ring may be reversed, face for
face in the field frame.
Any of the usual systems of circuit for armature windings may be employed,
and I illustrate a system of bar winding having peculiar connections of a character
readily lending itself to most any given system of armature circuits.
Referring now to Figs. 2 and 3:-
8, indicates the circular field-frame of a multi-polar machine:

page_text: 9, the bushing-ring disposed concentrically within the field-poles and around
the armature and carrying the commutation lugs and the compensating con-
ductors, which bushing-ring will be fully described later:
10, (see also Fig. 13) field-poles projecting inwardly from the field-frame and
bored to fit the exterior of the bushing-ring:
11, transverse slots in the field-poles, extending from the inner wall of the
field frame 8 to the inner faces of the poles and forming an air passage across the
poles:
12, projections from the roots of these slots, serving to divide the air currents
entering the faces of the poles and to direct them outwardly at each side of the
poles against the wall of field-frame 8:
13, the field-coils, which coils are wound upon a proper former and then
wrapped with cord and then put upon the field-poles, the opening in the coil being
somewhat larger than its field-pole, and the coil having a depth less than the
distance between bushing-ring 9 and the wall of field-frame 8 so that air spaces
are left between the coils and the parts supporting them:
14, (Fig. 12) the usual insulated wire on which the field-coils 13 are wound:
15, the cord wrapping applied to the field-coils:
16, studs projecting from the field-coils and held in place by the cord wrapping
thereof, the wrapping coming over the feet of the studs, and the heads of the studs
projecting such distance as to properly engage the surface of field-frame, field-
poles, and bushing-ring which support the coils, these studs being of insulating
material, as vulcanized fiber, and disposed over the faces and bore of the field-coils
in such frequency and position as to secure proper support for the coils which are
thus held away from the metal of the machine, securing insulation and circulat-
ing air spaces: and
17, interlocking circumferential ribs and grooves on the faces of field-poles 10
and on the periphery of bushing-ring 9, these ribs and grooves being symmetri-
cally disposed so that bushing-ring 9 may be reversed or turned face for face
within the pole-frame.
The bushing-ring 9 will now be described, reference being had to Figs. 2, 3, 4,
5, 6, and 7, it being understood that in Fig. 2. the coils of the bushing-ring are
generally shown, but in the upper part of the figure one coil is shown in section,
the next coil is omitted, leaving the bushing-ring empty, and in the position of
the next coil, the coil is omitted and its supports shown in section.
Referring to Fig. 4:-
18, indicates the commutation lugs projecting inwardly from the tire of the
bushing-ring 9, these lugs having the form of flat plates having feet at their inner
ends, which feet come close to but do not touch the armature, the lugs being of less
width than the tire of the bushing-ring, there being as many commutation lugs
as there are field poles the commutation lugs occupying angular positions midway
between the field-poles, as seen in Fig. 2:
19, a pair of lugs at each side of each commutation lug and similarly projecting
inwardly from the tire of the bushing ring, the lugs 19 being similar in construc-
tion to the commutation lugs 18, except that the lugs 19 have greater length than
the commutation lugs:
20, bridges extending across each end of each commutation lug 18, without
touching the commutation lug, and forming a strengthening tie between the
lugs 19 at each side of the commutation lug:
21, slots through the tire of the bushing-ring at each side of each commutation
lug and extending almost across the tire: and,
22, slots through the tire of the bushing ring and extending circumferentially
from near one pair of slots 21 to near succeeding pair, these slots being extended
nwardly entirely through lugs 19.
The bushing-ring thus presents the aspect of a hoop having plate-like lugs pro-
ecting inwardly from it, some of which lugs form the commutation lugs, the
others forming supports for the compensating coils. The inner face of the bush-

page_text: ing-ring is formed by the feet at the inner extremities of the lugs, the surface
being interrupted only by the slots between the feet and by the slots 22.
Between the lugs there are thus formed pockets in which the various coils may be
wound. The various slots interrupt the magnetic conductivity of the metal of the
bushing-ring, and the slots 22 form air passages entirely through the bushing-
ring and permitting air, as propelled by the armature, to pass through the bushing-
ring and between the field coils and also inside the field-coils through the slots 11
in the field-poles, the latter slots registering with slots 22. The bushing-ring,
after being properly wound, forms a structure complete within itself and held,
reversibly, by the field-poles within which it fits. The windings of the bushing-
ring will now be described, with reference to Fig. 5 in which is seen one complete
coil at a complete portion of the bushing-ring, a complete coil at a portion of the
bushing-ring shown in section through the set of lugs, and a similar set of lugs
shown in section with the coils of the winding shown diagrammatically.
Referring to Fig. 5:-
23, indicates a winding which when traced according to its arrow is found to
first pass around the commutation lug in a certain direction of winding, then pass
around a pair of extra lugs which straddle the commutation lug, then pass around
the outer pair of lugs in the set, these windings all being in the same direction,
then going on to and around the next commutation lug and then around the lugs
which straddle this second commutation lug, and then around the outer lugs of the
set, thus completing the second set of windings which are in a reverse direction
to the first set, the winding then going to the third commutation lug: and.
24, indicates the coil formed by each complete set of windings.
Each coil 24 therefore represents a winding on its commutation lug, and also
windings exterior thereto and supported by the lugs 19, the windings of the
alternate sets or coils being in one direction and the windings of the intermediate
sets or coils being in the other direction, the coils being connected up in series.
The windings of coil 24 correspond in their longitudinal elements, with the series
of conductors 3 seen in the diagram of Fig. 1, the curves at the ends of these wind-
ings being merely the connections to get the circuits through the longitudinal
portions of the windings. And by tracing the current in Fig. 5, in accordance
with its indicating arrow, it will be found that the direction of current is such as
to correspond with the diagram of Fig. 1 that is to say, all the currents flowing
across the bushing-ring between a given pair of commutation lugs will be found
flowing in one direction, and in the succeeding space between two commutation
Jugs the current will be found flowing in the opposite direction. In the diagram
of Fig. 1 notice that in the series of conductors 3 all those at the right hand
between poles 4 and 5 bear currents in one direction, and those at the left hand
hear currents in the reverse direction. The coils of the bushing-ring are in serie:
with each other and in series with the armature.
The commutation lugs 18 are each involved within a coil and are energized by
the entire coil and given a polarity due to the direction of winding. The other
Jugs 19, are practically unaffected by the currents in the windings, due to the fact
that these lugs are between conductors bearing currents flowing in the same direc-
tion. Referring to Fig. 2, it will be observed that a commutation lug 18 comes
midway between each pair of field-poles 10, and the winding is such that the
polarity of a given commutation lug is that of the leading field-pole. This is the
condition when the machine is used as a generator. When the machine is to be
used as a motor, the currents in both armature and compensating coils are reversed,
the direction of rotation remaining the same. Commutation lugs 18 are thus
caused to have the polarity of the trailing field-poles.
Only the armature remains to be described.
Referring to Figs. 8, 9, 10, 11 and 14:-
25, indicates the armature shaft:

page_text: , arms projecting radially from the hub and extending lengthwise of the
hub:
28, a ring at each end of these arms, the periphery of these rings and of the
arms being turned cylindrically to form the skeleton barrel of the armature:
29, annular clamp flanges bolted against the outer faces of rings 28 and forming
clamps to hold the armature disks:
30, bars of non-magnetic metal, as brass, disposed in longitudinal grooves in
the peripheries of arms 27, these bars lying about half their depths in the grooves,
the other half of their depths thus projecting outwardly from the periphery of the
armature barrel :
31, the armature disks, being thin iron plates having a bore fitting upon brass
ribs 30, the periphery of the disks forming the cylindrical outer surface of the
armature:
32, annular clamp flanges, of non-magnetic metal, as brass, fitting upon the
barrel of the armature between clamp flanges 29 and the ends of the series of
armature disks, these flanges 32 projecting outwardly to the full diameter of the
disks:
33, spaces provided at intervals along the series of armature disks:
34, radial bars disposed in the spaces 33, between the disks immediately at each
side of the spaces and riveted to those disks, as seen in Fig. 10, the spaces 33
therefore being formed by a pair of the disks secured to the separating bars:
35, radial slots in the disks and therefore forming slots extending lengthwise of
the entire series of disks, these slots being intended to receive the bars forming
the armature winding, the slots having a width suitable to this purpose and extend-
ing from near the periphery of the disks inwardly a sufficient distance to receive
the desired number of bars, the slots having a very narrow outward prolongation
through the periphery of the disks, and that portion of the slots just within this
narrow portion having a width greater than the remaining inner portion of the
slots so that an armature bar may be freely inserted endwise in the armature and
then forced down into the inner portion of the slots:
36, (Fig. 9) a special one of ribs 30 having superior outward projection so as to
engage in a notch formed in each of the armature disks, this special rib 36 there-
fore forming a key to bring the slots of the disk into registry and to prevent the
angular displacement of the disks upon the armature barrel:
37, outward prolongations of arms 27 at the commutator end of the armature:
38, a cylindrical hollow nose carried concentrically by the outer ends of the
arms 37:
39, the commutator hub fitting upon nose 38 and held thereon by set screws
screwing outwardly through nose 38:
40, the commutator clamp, being a ring fitting upon commutator hub 39 and
drawn thereon by bolts, the peripheries of the commutator hub and commutator
clamp having the form of dove-tail lips forming between them a dove-tailed
recess engaged by the commutator bars:
41, the commutator bars disposed as usual in circumferential series and insu-
lated from each other and having inward dove-tail projections engaged by the lips
of the commutator hub and clamp:
42, a lug projecting outwardly from the inner end of each commutator bar, this
lug being slitted lengthwise and radially to receive a thin metallic connecting
strip:
43, the armature bars disposed in the slots of the armature disks and extending
a considerable distance outwardly at each end of the series of disks, these bars
being provided with the usual insulation not shown, and the bars at their end's
being bent sidewise, as seen in Figs. 9, 11, and 14 so that one end of any given
bar may be brought into the neighbourhood of the similarly bent corresponding
end of any other given bar of the armature:
44, coupling bars riveted and soldered to the ends of any two armature bars
which are to be connected, these coupling bars being also bent, so that the cross

page_text: connection between two given armature bars is formed through bent portions of
the armature bars and the bent coupling bars:
45, similar coupling bars employed in connecting other pairs of armature bars,
the armature bars to be connected by the couplings 45 having less length than
those connected by couplings 44, the cross-connections between armature bars
being thus represented by short bars connected by couplings 45 and long bars
connected by couplings 44, couplings 44 coming outwardly beyond couplings 45:
40, connectors for joining the armature windings to the commutator bars:
47, arms projecting outwardly from clamp rings 29: and
48, rings carried by these arms in a position to come under the outer connected
portions of the armature bars.
It will be observed that the armature is so formed as to give free circulation of
air endwise through the barrel and within the commutator and within the bore of
the disks and outwardly through the spaces 33 distributed along the series of disks.
The properly insulated armature bars, while straight, are passed endwise
through the enlarged portions of the slots in the disks and then drifted inwardly
home in the slots, as many bars being put in each slot as the chosen system of
armature winding calls for, it being remembered that the peculiarities of my
machine, aside from the armature, permit of the employment of greater depth of
conductors in the armature than usual. In practice I have carried bar conductors
to a radial depth of six inches in the armature or more than half the magnetic
depth of the disks. The bars being properly placed in the armature, their ends
are then bent in accordance with the desired circuits and the couplings applied,
the result being an exceedingly compact system of connections lending itself to
any conceivable system of drum armature circuits. The projecting ends of the
bars and also the couplings should be well wrapped with insulating tape. Rings 48
should also be well insulated by wrapping. These rings give support to the pro-
jecting portions of the bars, Fig. 8 showing sufficient space left between the rings
and the bars to provide for the presence of the insulating wrapping. Connectors 46
should be thin and flexible to permit their being readily bent and carried from
any given armature bars to the proper commutator bar. The brushes and their
holding devices may be of any ordinary or suitable construction. No provision
need be made for adjusting the diameter of commutation, as there is no tendency
toward sparking in my machine, save such as might result from a rough com-
mutator or bad condition of brushes.
The improvements having been set forth in conjunction with a selected exempli-
fying type of machine, the formal modifications requisite in applying them to
other types of machines will readily suggest themselves to the skilled constructor.
What has been set forth represents the best mode in which I at present contem-
plate applying the principles of my invention.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what I
claim is:-
1. In a dynamo electric machine, the combination, substantially as set forth,
of a coil of wire having a binding wrapper, as of cord, and studs projecting from
the faces of the coil and having feet engaging under the wrapper.
2. In a dynamo electric machine, the combination, substantially as set forth,
of a field core provided with a dividing slot, and a coil disposed upon said core and
free therefrom so as to form an air space extending around the core and in com-
munication with the slot therein.
3. In a dynamo electric machine, the combination, substantially as set forth,
of a field frame, a core projecting inwardly therefrom and provided with a divid-
ing slot and with a projection inwardly at the root of the slot, and a coil disposed
upon said core and near said field-frame but free from the core and field-frame
so as to leave an air space in communication with said slot and extending between
the coil and core and between the coil and field frame.

page_text: 4. In a dynamo electric machine, the combination, substantially as set forth,
of a field-frame, having inwardly projecting field cores, cylindrically bored at
their faces, and a bushing-ring carrying coils, and having its periphery engaging
the faces of said cores.
5. In a dynamo electric machine, the combination, substantially as set forth,
of a field frame having inwardly projecting field cores cylindrically bored at their
faces, a bushing-ring carrying coils and having its periphery engaging the faces
of said cores, and circumferential rib and groove connections between the bushing-
ring and core faces to retain the bushing-ring sidewise.
6. In a dynamo electric machine, the combination, substantially as set forth,
of a field-frame having inwardly projecting field cores cylindrically bored at their
faces, a bushing-ring carrying coils and having its periphery engaging the faces
of said cores, and symmetrically disposed circumferential rib and groove con-
nections between the bushing-ring and core faces to retain the bushing ring side-
wise and to permit of its reversal within the field-frame.
In a dynamo electric machine, the combination, substantially as set forth, of
a field-frame carrying inwardly projecting cores and field-coils, an armature con-
centrically mounted within the field-frame, a bushing-ring carrying coils and
encircling the armature and supported by the cores of the field-frame.
8. In a dynamo electric machine, the combination, substantially as set forth,
of a field frame provided with poles and magnetizing coils, an armature, and a
ring carrving coils and interposed between said armature and field-frame.
9. In a dynamo electric machine, the combination, substantially as set forth,
of a field-frame carrying inwardly projecting core and field coils, an armature
concentrically mounted within the field-frame, a bushing ring encircling the
armature and supported by the cores of the field-frame, and a circumferential series
of conductors carried by the bushing-ring and disposed parallel with the axis of
the armature.
10. In a dynamo electric machine, the combination, substantially as set forth,
of a field-frame carrying inwardly projecting cores provided with field-coils, an
armature mounted concentrically within the field-frame, a bushing-ring surround-
ing the armature and supported by the field-frame and provided with passages
extending through it parallel with its axis, and conductors extending across the
bushing ring through said passages.
11. In a dynamo electric machine, the combination, substantially as set forth,
of a field-frame carrying cores and field-coils, an armature mounted concentrically
within the field-frame, a bushing-ring surrounding the armature and supported
by the field-frame and having passages through it parallel with its axis, and con-
ductors disposed within said passages and joined at each side of the bushing-ring
to form a circumferential series of coils carried by the bushing-ring.
12. In a dynamo electric machine, the combination, substantially as set forth,
of a field-frame carrying cores and field coils, an armature mounted concentrically
within the field-frame, a bushing-ring having a tire fitting within and held by
the field cores and provided with lugs extending across the tire and projecting
inwardly to near the armature, and coils formed of conductors wound upon said
lugs.
13. In a dynamo electric machine, the combination, substantially as set forth,
of a field-frame carrying cores and field-coils, an armature mounted concentrically
within the field-frame, a bushing-ring comprising a transversely and circum-
ferentially slotted tire, and slotted lugs projecting inwardly from the tire to near
the armature, and coils formed by conductors wound' upon said lugs.
14. In a dynamo electric machine, the combination, substantially as set forth,
with a field-frame and armature, of a tire having pairs of transverse slots and
having, circumferential slots between the pairs of transverse slots, commutation
lugs projecting from the tire between each pair of transverse slots, additional lugs
projecting from the tire between the commutation lugs and divided by inward

page_text: prolongations of said circumferential slots, and coils formed by conductors wound
on said lugs.
15. In a dynamo electric machine, the combination, substantially as set forth,
of a field-frame, cores projecting therefrom and having dividing slots, coils on
said cores, a tire supported by said cores and having circumferential slots register-
ing with the slots in said cores, lugs projecting inwardly from the tire, and coils
formed by conductors wound upon said lugs.
16. In a dynamo electric machine, the combination, with a field-frame and
armature of a ring interposed between said field-frame and armature and carrying
compensating coils.
17. In a dynamo electric machine, the combination, substantially as set forth,
with a field-frame and armature, of a slotted tire, lugs projecting inwardly from
the tire and having less width than the tire, additional lugs projecting inwardly
from the tire between the first mentioned lugs and having a greater width than the
first mentioned lugs, bridges extending across the ends of the first mentioned lugs
and connecting the lugs immediately at each side of the first mentioned lugs, and
coils formed by conductors wound upon said lugs.
18. In a dynamo electric machine, the combination, substantially as set forth,
with a field frame and armature, of a tire held by the field-frame, lugs projecting
inwardly from the tire and provided with inner feet cylindrically bored to form a
chamber for the armature, and coils wound upon said lugs between said tire and
feet.
19. In a dynamo electric machine, the combination, substantially as set forth,
of a field-frame carrying cores and field coils, an armature mounted concentrically
within said field-frame and having a diameter less than the bore of the series of
field-cores, a circumferential series of coils disposed around the armature between
the armature and the field-cores, and a metallic support for said last mentioned
coils and connected separably with the field-frame.
20. In a dynamo electric machine, the combination, substantially as set forth,
of a field-frame carrying inwardly projecting cores, field-coils on said cores, an
armature mounted concentrically within the field-frame and having a diameter
less than the bore of the series of field-cores, coils disposed in circumferential series
around the armature between the armature and the field-cores, the last mentioned
coils having longitudinal elements parallel with the axis of the armature, and the
axis of each of said last mentioned coils coming midway between the axis of the
pair of field cores, and a support engaging said field-cores and said last mentioned
coils.
21. In a dynamo electric machine, the combination, substantially as set forth,
of a field-frame carrying cores and field-coils, an armature mounted concentrically
within the field-frame and having a diameter less than the bore of said field-cores,
fixed conductors parallel with the axis of the armature and disposed in circum-
ferential series around the armature between the armature and the field-cores,
and connections to convey current through said conductors in direction opposite
to that followed by the current flowing through contiguous conductors in the
armature.
22. In a dynamo electric machine, the combination, substantially as set forth,
of a field frame carrying cores and field-coils, an armature mounted concentrically
within the field-frame and having a diameter less than the bore of the series of
field-cores, fixed conductors parallel with the axis of the armature and arranged
in circumferential series between the armature and the field-cores, and connections
between said fixed conductors and the armature to convey the current traversing
the armature conductors through said fixed conductors in such direction that the
current flowing in each of said fixed conductors will magnetically oppose that
flowing in the contiguous armature conductor.
23. In a dynamo electric machine, the combination, substantially as set forth,
with a field-frame carrying cores and field-coils, and an armature mounted within
the field-frame, of fixed conductors parallel with the axis of the armature and

page_text: disposed in circumferential series around the armature, connections conveying
current through said fixed conductors in direction to magnetically oppose the
currents Howing through contiguous armature conductors, commutation lugs
disposed between the field-cores and magnetically energized by the currents flow-
ing in said fixed conductors.
24. In a dynamo electric machine, the combination, substantially as set forth,
of a field-frame carrying cores and field-coils, an armature mounted concentrically
within said field-frame and having a diameter less than the bore of the field-cores,
a commutation lug disposed octween each pair of field-cores and presenting a pole
to the armature, additional similar lugs disposed between said commutation lug,
and coils formed by winding a conductor first upon a commutation lug and then
outside the pair of additional lugs at each side of the commutation lug.
25. In a dynamo electric machine, the combination, substantially as set forth,
of a field-frame carrying cores and field-coils, an armature mounted concentrically
within the field-frame and having a diameter less than the bore of the series of
field-cores, and a series of fixed coils disposed around the armature between the
armature and the field-cores, the coils of said series alternating in direction of
winding.
26. In a dynamo electric machine, the combination, substantially as set forth,
of a longitudinally grooved armature barrel, ribs of non-magnetic metal disposed
in said grooves, a series of disks with their bores engaged by said ribs, and clamps
secured to the armature barrel and engaging the end of the series of disks.
27. In a dynamo electric machine, the combination, substantially as set forth,
of an armature barrel, a series of disks thereon and provided with a circum-
ferential series of radial slots, each slot being widened at its outer portion, and
clamps carried by the armature barrel and engaging the ends of the series of disks.
28. In a dynamo electric machine, the combination, substantially as set forth,
of a longitudinally slotted armature bar disposed withim said slots and projecting
endwise from the body of the armature, bends formed upon the projecting ends of
said bars to bring the ends of a pair of bars toward each other, and flat coupling
strips united to and connecting the ends of such pair of bars.
29. In a dynamo electric machine, the combination, substantially as set forth,
of a longitudinally slotted armature, bars disposed in said slots and projecting.
endwise from the body of the armature, bends formed upon the projecting ends of
said bars to bring the ends of a pair of bars toward each other, connections between
the ends of such pair of bars, and rings concentrically carried by the armature
within the projecting connected ends of the bars and forming a support for such
projecting ends.
30. In a dynamo electric machine, the combination, substantially as set forth,
of an armature hub, arms projecting endwise therefrom, a hollow nose carried
by said arms, and a commutator hub having its bore fitting upon said nose.
31. In a dynamo electric machine, the combination, substantially as set forth,
with balancing coils for neutralizing armature reaction, of a bushing-ring carry-
ing said balancing coils and supported by the field frame.
32. In a dynamo electric machine, the combination, substantially as set forth,
with balancing coils for neutralizing armature reaction and disposed within the
main field of magnetic forces impressed upon the armature, of commutation lugs
passing through the centers of said balancing coils and energized solely by said
coils.
33. In a dynamo electric machine, the combination, substantially as set forth,
with balancing coils for neutralizing armature reaction, of a bushing-ring carry-
ing said balancing coils, and commutation lugs passing through the centers of
said balancing coils and energized thereby.
34. In a dynamo electric machine, the combination, substantially as set forth,
with balancing coils for neutralizing armature reaction, of a bushing-ring
formed of magnetic material and carrying said balancing coils, and commutation
lugs passing through the centers of said balancing coils and energized thereby.

page_text: 35. In a dynamo electric machine, the combination, substantially as set forth,
with an armature and a field frame and cores, of a ring carrying balancing coils
and commutation lugs contiguous to the armature.
ALLISON BROS.,
Agents for the Applicant.