IMPROVEMENTS IN DYNAMO ELECTRIC MACHINES, SYSTEMS " OF ELECTRICAL CURRENTS AND MEANS FOR PRODUCING CONTROLLING AND REINFORCING SAID CURRENTS
Year: 1883

page_text: LETTERS PATENT to Sydney Pitt of Sutton in the County of Surrey for
an Invention of IMPROVEMENTS IN DYNAMO ELECTRIC MACHINES, SYSTEMS
"
OF ELECTRICAL CURRENTS AND MEANS FOR PRODUCING CONTROLLING AND
REINFORCING SAID CURRENTS Communicated to him from abroad by
Nathan Huntley Edgerton Electrician a Citizen of the United States
residing at Philadelphia in the State of Pennsylvania
COMPLETE SPECIFICATION filed by the said Sydney Pitt at the Office of
the Commissioners of Patents on the 16th June 1883.
IMPROVEMENTS IN
SYDNEY PITT of Sutton in the County of Surrey
DYNAMO-ELECTRIC MACHINES, SYSTEMS OF ELECTRICAL CURRENTS, AND MEANS
FOR PRODUCING, CONTROLLING, AND REINFORCING, SAID CURRENTS Communi-
cated to me from abroad by Nathan Huntley Edgerton, Electrician a Citizen of
the United States residing at Philadelphia in the State of Pennsylvania
The object of my invention, broadly stated, is the construction of a bi-polar
machine from which one or a series of separate and distinct currents can be derived
or produced, and to such end my invention, broadly considered, comprehends a
system of coupling entirely distinct from any heretofore devised, and special
constructions of the armature, commutator, and field magnets, enabling such
coupling, and hereinafter described at length. Specifically considered these special
constructions comprehend a revolving armature made in separate pieces or bobbins
arranged in opposite pairs and wound with connected coils the terminals of which
are opposite pairs of roller contacts carried by and revolving with the armature-
a special construction whereby my armature is made to conform more nearly to
the action of the Paccinotti Ring;-comprehend, also, a casing composed of two
oppositely placed semi-cylindric shells to each of which are connected, in sots of
three, radial cores which carry and support in fixed relation two opposite semi-
cylindric inducing surfaces or pole pieces concentric with the shells, constituting
the poles of the machines, and made so as not to meet each other but to leave an
axially disposed open space constituting a neutral zone between the fields;-and
Price 8d 1
-

page_text: comprehends, finally, a fixed commutator composed of a series of segments, two of
which I term the minor segments, connect together electrically, and in the set of
the machine dispose in such manner as to register within the area of the neutral
zone of the machine, and two of which I term the major segments, arrange to
register within the influence of the field magnets, and either make single when the
machine is especially constructed with a view to the production of but a single
field current, or else divide into two (or if desired more) sets when the machine is
especially constructed with a view to the production of two or more field currents ;—
--said-commutator,-whatever_be_the_specific_arrangement of its segments, being
preferably cylindriform, fixed to receive the tread of the bobbin terminal contacts,
and having the terminals of the wires of the exterior circuits-whether field or
subsidiary connected with its segments. In the accompanying drawings which
form a part of this specification, and in all such views of the same as depict a
commutator, with the exception of Figures 20 and 21, said commutator is either
represented or supposed constructed with two sets of major segments so as to
adapt it for the taking off of two field currents,
Figure 1 represents. in top plan sectional view a preferred form of apparatus
conveniently embodying my invention (section being supposed in a horizontal
plane projected on the dotted line aa of Figure 2), the wires of the exterior
circuits not being represented but the wires of one pair of armature bobbins,
composing the armature circuit of such pair, being represented. Figure 2 is n
side elevational view of the same apparatus. Figure 3 is an end elevation of the
same apparatus, viewed from the left hand side of Figure 1 and representing the
coupling and arrangement of wires resorted to when it is desired to produce two
main and one subsidiary circuit. Figure 4 is a view similar to Figure 3 and
similarly viewed, representing the coupling and arrangement of wires resorted to
when it is desired to produce one main current for the operating of lamps, or for
other work, and another main current for the reinforcement of the fields; the
armature for clearer illustration is omitted from this view, as are also the wires of
the subsidiary circuit. Figure 5 is a transverse sectional elevation in planes
projected on the dotted line b-b of the armature in Figure 1, representing a
convenient construction of armature.
Figure 6 is a transverse sectional view of a modified construction of armature,
section being supposed in a diametric plane projected on the dotted line c―c of
Figure 7, which last named figure is a longitudinal sectional detail on the line e-―e
of said Figure 6. Figure 8 is a transverse sectional clevation, on a. diametric
plane projected on the dotted line of Figure 9, of yet another modified
construction of armature, and Figure 9 is a longitudinal sectional detail of the
armature of Figure 8 taken on the line g-g of said Figure 8. Figure 10 is an
end elevation of that extremity of the armature (supposed removed from the
inachine) which carries the roller contacts or bobbin terminals, representing also,
in diametric section on the dotted line jj of Figure 13, the commutator and
the application of the discharging wire to the ininor segments thereof when such
wire is inade simply long enough to effect the lischarge necessary to the demagnet-
ization of the successive pairs of bobbins of said armature and is not prolonged to
form a subsidiary circuit. Figure 13 is a vertical longitudinal central sectional
elevation, in the plane of the dotted line k-k of Figure 10, of one of the hubs of
the armature, the insulating plate of the armature, one pair of bobbin terminals,
and the commutator. Figure 11 comprehends three views of a convenient form
of spool for the cores of the field magnets. Figure 12 is an end elevation of one
of the pole-pieces and its cores, removed from the casing. Figure 14 is a view in
perspective, partially sectional, of the commutator and certain of the bobbin
terminals of the armature, drawn with a special view to the representation of an
arrangement of the two separate sets of commutator segments and a construction
in which four pairs of armature bobbins are employed. Figure 15 is a longitudinal,
sectional detail of one of the bobbin terminals representing a preferred method of
application of its roller contact. Figure 16 is a perspective detail of a preferred

page_text: form of bobbin spool for the armature, it being of the character represented in
either Figures 6 or 8.
Figure 17 is a similar view representing one of the screws which secure the
spools in place upon the hub of the armature. Figure 18 is an end or face elevation
looking from the armature of a modified construction of commutator made in disk
form and having the segments upon its face,-the armature shaft being represented
in section on the line v-v of Figure 19, and the roller contacts which travel upon
the face of the commutator being represented in dotted lines. Figuro 19 is a
soctional view of the same and of the insulating plate and bobbin terminals of the
armature, section of the commutator being supposed upon planes projected through
the dotted lines ww of Figure 18, and the sight being taken from below upwards
with respect to said Figure 18. Figure 20 is a view in perspective illustrative of
a form of commutator in which each of the two adjoining major segments are
undivided diametrically by a mica plate and made as a single piece, this arrange-
ment of my commutator being that preferably adopted when I desire to employ
my apparatus for the production of but one exterior field circuit, the commutator
then being.composed of but four segments, two minor segments which in the set
up of the machine register within the area of the neutral zone and two major
segments which register within the area of influence of the field magnets.
Figure 21 is a diametric section through the commutator of Figure 20. Similar
letters of reference indicate corresponding parts in all the figures. A preferred
form of a convenient embodiment of my invention is, as stated, represented in the
above described drawings; certain modifications of the structure of certain parts
also represented, and all hereinafter described.
In the accompanying drawings, A represents a base from which is erected two
semi-cylindric and oppositely placed shells B which form in connection with tho
base the inclosing casing or frame work of the machine. As a preferred
construction the shells and base are cast of iron as a connected whole. At the top
the shells are divided so as not to meet and the oponing between them is bridged
by a suitably shaped plate C of dia-magnetic material such as brass, which is
fixedly connected in place to the shells and which when in place completes the
cylindriform contour of the structure. This casing forms the support for tho
devices composing the two field magnets and for the bearings within which is
journalled the shaft of the revolving armature; it also serves as a keeper for the.
exterior poles of all the cores of the field magnets. D D are respectively the
positivo and the negative pole pieces of the machine, being segments of soft iron
disposed oppositely to each other and concentrically with respect to the semi-
cylindric shells of the casing. Neither of these pole pieces is sectionally a complete
Soini-circle, but both stop short of so being in order to leave between their
adjacent sides open spaces which constitute the neutral zone E of the machine.
The semi-cylindric inducing surfaces are the positive and negative pole pieces
which form the poles of the machine. Both pole pieces are provided as to their
exterior surfaces with three radial cores d d which, preferably, have each two
parallel flat sides and two rounded edges and are of length sufficient to span the
cylindriform interspace between the exterior surfaces of the pole pieces and the
interior surfaces of the semi-cylindric shells, so that through the instrumentality of
bolts or kindred connecting devices F the cores can be rigidly affixed to the shells
so as to retain the pole pieces in proper position with respect to each other and
relatively to said shells. The cores are preferably cast with the pole pieces and
are, whether cast or formed as separate members, composed of iron. G are spools
formed of brass or other dia-magnetic material, conformed to the cores, and
adapted to be slipped thereupon prior to the affixing of the cores within the shells.
These spools are of the usual flanged construction and aro adapted to receive tho
helices of insulated wire by means of currents through which the field magnets
are energized. The application of the various helices to those spools is hereinafter
described. The casing is provided with any desired number of binding posts H
for the wires of the spools. The length of the casing may be varied, as may be

page_text: also the length of the pole pieces, although it is preferable that the length of the
pole pieces should not exceed that of the casing. The general dimensions also may
be varied at will. If desired more than one set of three cores may be applied to
each pole piece, but the additional sets must be in corresponding series of three,
radially disposed, in the same longitudinal planes, and otherwise of essentially the
same construction as that series hereinbefore described and illustrated in the
drawings.
The increase in series would simply be with a view to augmenting the power of
the machine.
I is a shaft axially journalled with respect to the casing in bearings i supported from
brackets J sprung from the semi-cylindric shells as represented, or supported upon
standards erected-from-the-base, or otherwise-connected-or-applied-as-convenience_
of manufacture may dictate. The shaft is driven through the medium of a pulley K
actuated by a motor, or is otherwise caused to rotate.
The shaft is equipped with the rotating armature which is provided with
terminals for its bobbins which terminals revolve in fixed connection with the
armature. Heretofore revolving armatures have been formed of a series of
detachable parts, in order that the coils which form the bobbins may be first wound
upon the proper parts and the latter then assembled and by suitable means bound
together so as to constitute a connected whole or armature proper. I prefer to
resort to this sectional structure, and have herein illustrated and described several
constructions alike embodying this idea, either one of which may with equal profit
be resorted to and all of which are illustrated in the drawings.
Said constructions are alike in that they all make use of detachablo bobbin
spools and vary only in the mechanical devices by which said spools may be
secured to the hubs which carry them.
L, Figures 1, 5, 6, 7, 8, 9, -13, and 17 are hubs or disk shaped plates fixedly
secured at a predetermined distance apart upon the shaft and designed to carry
and have secured to them the bobbin spools M, Figures 1, 5, 6, 7, 8, 9, 10 and 17.
The bobbin spools are composed of segmental pieces or webs, designated by the
letter m, of a predetermined length and bounded by radial flanges m* of slightly
greater length.
Any given series of these spools depending upon their proportions, that is to
say, upon the breadth of their segmental pieces, may be employed. I have
represented constructions in which respectively eight (Figures 5 and 6) and
sixteen (Figure 8) of these spools are employed. The coils of insulated wire which
form the bobbins N of the armature are wrapped longitudinally around the
seginental pieces between the radial flanges of these bobbin spools to a depth
necessary to fill the space up to the height of the flanges, preferably before the
spools are assembled and connected. One extremity of each of these bobbin coils
is connected with one of the revolving terminals of the armature and the other
extremity is popularly speaking, continued on as the coil of the diametrically
opposite bobbin, the outer extremity of which is connected with the revolving
terminal diametrically opposite to the terminal first mentioned. Three methods,
mechanically different but operating to the same result, of connecting these bobbin
spools to the hubs are represented in Figures 1, 5, 6, 7, 8 and 9. In Figure 5,
spokes are sprung radially from the hubs in sets of two and embrace two
contiguous flanges of adjacent bobbin spools, rigid connection being effected by
means of bolts *, or if desired by other means. In this construction a central
web is sprung from the exterior surface of the segmental pieces of ouch bobbin
spool so as to divide each of the latter in such manner that two separate coils
forming bobbins can be applied with each bobbin spool. This is an optional
construction which may also be resorted to with the other attachments of bobbin
spools hereinafter described. In Figures 6 and 7 the extremities of the flanges
of the bobbin spools are notched as at n, and the bobbin spools are let into
radial recesses of in the perimeter of the hubs, and held in place by a band or
ring of metal O which is fitted over the hub and over the projecting extremities
:

page_text: of the flanges beyond the notched portion and is connected by screws o* or
kindred fastening devices with the hub. In Figures 8 and 9 the bobbin spools
are simply placed side by side upon the hubs made with smooth perimeters, and
connection with said hub is conveniently effected by means of suitably shaped
screw bolts P or kindred devices, as well represented in Figures 7, 9 and 17.
I might proceed to illustrate other constructions whereby the bobbin spools can
be conveniently secured in their assembled relation to the hubs or to the shaft
direct, but I regard the three foregoing constructions as ample for the illustration
of a convenient practical construction of a sectional revolving armature. The shaft
of the armature is made of steel, the hubs are made of brass or other dia-magnetic
material to prevent the setting up of magnetic circuits through the armature, and
the bobbin spools are made of soft iron. At that extremity of the armature which
is adjacent to the commutator, and which, I may premise, may, according to the set
of the commutator, be either extremity of the armature, the hub and the extremities
f the bobbin spools on that end are covered by or equipped with a plate of insu-
lating material Q of ebonite or kindred non-conducting material. R are the bobbin
terminals, being arms of metal or other conducting material, preferably longitudinally
projected from or aflixed to the insulating plate of the armature.
The bobbin terminals are of any convenient form and construction,-in the con-
struction represented they are parallel with the shaft, and contain the outer
extremities of the insulated wires forming the bobbins of the armature, which wires
are represented as imbedded in their substance, but which may be connected to
them by means of binding posts, soldering, or other convenient method. These
bobbin terminals are arranged in diametrically opposite pairs, and each terminal is
attached to the terminal extremity of one of the coils of wire formning one of the
arinature bobbins. A convenient form of construction is represented in detail in
Figures 10, 13, 14 and 15 of the drawings, in which r are depending slotted lugs
forining a housing at the extremity of each terminal within which housing is con-
tained a frame r¹ supporting the axle r¹ of a rotating contact S, or metal roller. Each
frame is connected with its housing by a metallic spring r* so as to be constantly
under the influence of a force tending to press it and its roller contact from out the
housing. The axles are conveniently guided in slots formed in the depending lugs
of the housing. These roller contacts, in which the bobbin terminals considered as
an entirety end, travel over the surfaces of the commutator, and are preferably of
such breadth as to their tread and provided in such numbers as, in the aggregate of
their paths, to cover the entire length of the surface of the commutator. These
bobbin terminals are provided, as stated, in diametrically opposite pairs and it is a
prerequisite where a commutator having two sets of major segments is employed
that the roller contacts of each pair should tread upon the same set of segments of
the commutator and not upon separate sets.
↓
In the set of the machine the roller contacts of the bobbin terminals when in
place over the surfaces of the commutator are held in constant and forcible contact
therewith by the expansion of their springs. In the event of the racing of the
engine or other motor employed to drive the armature, whereby such excessive
rapidity of revolution would be imparted to said armature as to occasion through
the generation of an excessive current damage to the lamps and the machine itself,
the increased centrifugal force causes the raising of the roller contacts from the
face of the commutator and the compression of their springs, thereby breaking the
contact and averting the disastrous consequences otherwise, in the absence of special
provision, necessarily resulting. It is proper for me to say here that other forms
of contacts than rollers can be substituted in the bobbin terminals with the samo
result electrically, and that other constructions of housing and frame for my roller
contacts can be substituted in the stead of those represented and described, while
the shape and method of application of the bobbin terminals may be varied at
will provided the essential features of arrangement hereinbefore mentioned aro
retained.
The commutator, best shown in Figures 1, 10, 13, 14, 20, and 21, is conveniently

page_text: affixed to a sleeve T; formed of bronze or other metal adapted to resist frictional
wear, which in effect constitutes a bushing of the shaft and which is flanged into
or connected by flanges t with one of the bearings of the shaft, as clearly shown in
Figure 14. Upon the sleeve is affixed or rigidly mounted what I term a com-
mutator head Ù, being a fixed disk of ebonite or kindred non-conducting material
which is conveniently provided with a correspondent series of circuit binding
posts in which the opposite extremities of the wires of the various exterior
circuits terminate, but which may receive the terminal extremities of the wires
of said circuits by having them suitably imbedded therein and electrically connected
with the sets of segments. V is a tube of ebonite or other non conducting material,
closely circumscribing the sleeve of the commutator and affixed thereto, and, if
desired, made as a projecting tubular-boss of the commutator-head. This tobe-is-
completely and closely enveloped or surrounded by a hollow cylinder of copper or
other conducting metal, which is divided longitudinally to form what I term major
or long segments W W and minor or short segments X, the divisions between
which segments are filled by properly shaped pieces of mica, glass, or kindred insu-
lating material, Y. The cylinder aforesaid, which, considered as an entirety, is
composed of these segments is, as an expedient of manufacture, formed of two
-concentric metal annuli, similarly divided into the segments, so that when the seg
ments of the exterior annulus wear under the tread of the roller contacts, they, said
exterior segments, may be replaced upon the unworn segments of the interior
annulus. The commutator is so disposed in the set of the apparatus that its short
segments register within the plane or area of the neutral zone, The major segments,
in the construction of apparatus represented in the drawings are either divided into
a right and left hand set each composed of two opposite muajor segments as especially
illustrated in Figure 14 and respectively designated in said figure by the letters
W W¹, or else are each single and undivided by the mica plate as represented in
-figures 20 and 21, the latter arrangement being one to which, as stated, resort is
had when it is desired to construct my apparatus especially for use in the pro-
duction of a single exterior field circuit as herein fully explained. The minor
segments are preferably undivided diametrically and consequently are of double the
longitudinal extent of the major segments and common to both sets. The right
and left hand sets of major seginents are divided from each other by a suitably
shaped plate of mica or other insulating material extending down to the ebonito
tube, and are similarly divided from the common minor segments.
Y designates these mica plates which are best illustrated in Figure 14. In the
form of commutator represented in Figure 14 and in which two sets of major
segments are employed, the tread of any pair of the roller contacts is wholly upon
either the right or the left hand set of major segments, traversing of course the
common minor segments, and is never upon the mica plates which diametrically
divide said right and left hand sets of major segments. I have spoken of the
circuit binding posts u as erected from the commutator head. It is, however,
obvious that if the terminal extremities of the several exterior circuits are suitably
imbedded or entered into the proper segments of the commutator, the binding
posts may be wholly dispensed with, or, if desired, placed upon the brackets J
which support the bearings of the shaft, or upon other supports. Z is the bobbin
discharging wire removably applied to connect the minor segments in the manner
indicated in Figuro 10, it being introduced through the ebonite tube of tho
commutator in the manner shown. The office of this discharging wire is to enable
the demagnetization of a given pair of bobbins of the armature as hereinafter
more fully described. The terminal extremities of the wires of the several circuits
are imbedded in or connected with opposite pairs of segments, as hereinafter fully
described.
Having now described a preferred construction of an apparatus conveniently,
simply and cheaply embodying my invention,-before proceeding to a description
of the manner in which I utilize said apparatus either for the production
of one or two main currents, or for the production in connection with either

page_text: one or two main currents of a subsidiary current, or for the equal distribution
of one main current for reinforcing the magnetization of the field magnets, or for
the demagnetization of given pairs of arinature bobbins and the consequent increaso
in value of the main currents, it is proper for me to state that the operation of
my apparatus, electrically considered,-that is to say, the operation of the armature
in the energizing of the field magnets and of the commutator as such,―is the
sume as in other forms of dynamo-electric machines heretofore known, The
operation of my machine, mechanically considered, arises from the revolution of
the shaft and the rotation thereby of the armature through the magnetic fields (in
which a certain amount of residual magnetism is presupposed) so as to energize
the latter, with the result of enabling the utilization of the induction arising from
such energizing action for the creation of electrical currents in the armature, and
for the passage thereof throughout exterior circuits, under and subject, of course,
to the operation of the commutator in the transfer of such currents. The object
of my invention being, as hereinbefore stated, to enable the creation of different
currents from a single bi-polar nachine, it is to be understood that the machine
has its wires differently coupled or connected for the production of the different
currents-thus, one system of coupling and arrangement is necessary when the
apparatus is to be utilized for the production of but a single exterior or main
current, another when for the production of two exterior or main currents, another
when for the equal energizing or reinforcement in magnetization of the field
magnets by one exterior current employed in connection with another exterior
current, and still another when the demagnetization of a given pair of armature
bobbins is utilized for either the discharge of such bobbins into each other or for
the production of a subsidiary current. I now proceed to describe the several
systems of coupling which are capable of application and resorted to in connection
with a commutator having two sets of major segments and of the character
especially illustrated in Figure 14, it being borne in mind that the above is the
form of commutator which I have especially designed for use in the production of
two field currents.
Assume that I desire to set up a current in a single exterior circuit for the
running, for instance, of arc lamps :-I couple one extremity of an insulated wire
with one of the circuit binding posts communicating with one of the long segments
of the commutator, or connect it with said segment direct, and carry such wire in
coils around the spools of one field magnet in succession, and then carry the wire
off through an exterior circuit, provided if desired with lamps, and back again to
the spools of the opposite field magnet, wind it around them in opposite succession,
and connect the extremity beyond the last spool to that circuit binding post which
communicates with that long segment which is diametrically opposite to the long
segment to which the first end of the wire has been described as attached, or to
the given long segment itself. In the production and setting up of a current
through this circuit, I utilize all the bobbin spools of the armature, which spools
are previously wound in opposite pairs. Ench pair of the bobbin spools of the
arinature is wound in the following manner:-A wire leading from one of the
bobbin terminals is wound lengthwise around one of the bobbin spools employed
in connection with said terminal, as shown in Figure 1, a wire leading from tho
diametrically opposite terminal is correspondingly wound around the diametrically
opposite spool, and the finishing ends of the two wires so wound are connected
together across the breadth of the armature. Whatever may be the coupling or
setting up of the apparatus, the bobbins of the armature are preferably wound in
the above manner and placed in opposite pairs, the corresponding extremities of
the wires forming the coils on the opposite bobbins being connected with opposite
bobbin terminals. As a matter of course in the above arrangement it will be
necessary to electrically connect together the adjoining major segments of the two
sets or pairs of major segments, which may be readily done by simply carrying a
separate wire from each of the two major segments which, in the commutator are
side ly side (for-instance, the two segments lettered W W and shown in

page_text: Figure 14) and connecting the wires at points either immediately outside of the
commutator or upon or near the casing of the magnetic fields, and of course
making similar connections for the two adjoining major segments which are
respectively the opposite neighbors of the two first considered.
It is convenient to attach these connecting wires to terminals on the casing, and
between these terminals it is of course easy to establish the required connection
by inserting a short conducting wire extending from one terminal to another,
without in any manner rearranging the commutator segments themselves. Some
connection between the pairs of major segments must, of course, be made, or else
all the roller contacts of the armature must be arranged to tread upon that set or
pair of major segments which alone is in connection with the wires of the field
-circuit,-as-should-any-pair or pairs of these contacts_trend_upon that set or pair of
major segments which is not so connected, said contacts would be inert for the
transmission of an armaturo current through the bobbins connected with them.
As this latter arrangement, which presupposes that all the roller contacts are set to
tread upon one pair of major segments only, would manifestly necessitate means of
adjustment in the length of bobbin terminals, it is obvious that the connection of
wires first described is the better practice to resort to. I do not, however, restrict
myself to a connection between the wires of the two adjoining major segments,
as it is manifest that a connection can be made between the wires of diagonally
opposite major segments, which while productive of one current only would result
in the setting up of a current of higher intensity than when adjoining segments
'were connected. A removable wire arranged to bridge the mica plate which
diametrically divides the adjoining major segments and to have its ends imbedded
in said segments would, of course, occasion the electrical connection of the adjoining
segments, and, for the time being, practically convert the two pairs of major
segments into one. It is proper for me in this connection to state that, although
it is perfectly easy-os above set forth-to make such a connection between the
major segments of a commutator having two sets of major segments upon both of
which the bobbin terminals are set to travel as shown in Figure 14, as will connect
said major segments electrically and enable the taking off of a single field current,
yet that a commutator in which the major seginents are divided into two sets is
especially designed and adapted for the taking off of two field currents, and that
when but one such current is desired I prefer to employ a commutator in which
the major segments are not divided and such for instance as is illustrated in
Figures 20 and 21. A connection and arrangement of the character above described
is analogous as to its results to the results attained by well known dynamo-electric
machines, differing only from them in that the arrangement of the field magnets
in my apparatus insures more thorough induction. In an arrangement of the
character above described for the production of a single exterior current, it is
important in order to secure maximum energy in the fields that each pair of
armature bobbins at the moment of passing from a given field to the opposite
field should be thoroughly demagnetized or discharged of their residual magnetism,
but this has been impossible in any machine heretofore constructed. I have
discovered that this demagnetization of the armature bobbins in successive pairs
can be accomplished at the moment when each pair of bobbins registers in the
plane or within the area of the neutral zone of the fields and at the moment when
no current is being generated in said pair of bobbins by either magnetic field, by
providing a metallic connection such, for instance, as the discharging wire Z
(Figure 10) between the minor segments of the commutator, which latter, it will
be borne in mind, are in the set of the machine also fixed to register in the plane
or within the area of the neutral zone, and that by the provision of this metallic
connection, each bobbin of the pair for the time being in the plane or within the
area of the neutral zone, through the instrumentality of its roller contacts and
during the period of their tread upon said minor segments, discharges itself through
the said metallic connection into the other bobbin, so that the oppositely flowing
currents of the two bobbins neutralize each other and thorough demagnetization
i

page_text: in the pair of bobbins under consideration results. While the result of the
neutralization of the current of each pair of armature bobbins in the above manner
is the demagnetization of all the bobbins-with the further result that the ener-
gizing the field magnets is facilitated, yet the current of each pair of bobbins.in
turn is lost for useful work. I have also discovered that the bobbin currents so,
as above, 'lost by discharging through the wire Z represented in Figure 10, can be
utilized by prolonging said wiro to form a subsidiary exterior circuit the current
through which is capable of doing work, such for instance, as the running of
incandescent lights, and is a subsidiary current composed of the several currents of
the armature bobbins. This arrangement of a subsidiary circuit is illustrated in
Figure 3, said circuit being represented by the parallel dotted lines designated as
No: 4. The wires of this circuit No: 4 are led off from terminals in connection
with the minor segments of the commutator, and are in Figure 3 represented as
occupying a position in a horizontal plane projected through the commutator head,
said position, under a predetermined estimated speed of the armature, being sucli
as to occasion registry within the area of the neutral zone. 1* represent incan-
descent lights upon said subsidiary circuit. It will, I think, now be understood,
that while I have in the above manner attained the result of a thorough demag-
netization of all the pairs of bobbins of the armature at the proper time, that is,
at the instant when each pair of bobbins is passing from the influence of one field
to that of the other, and have thus increased the potency of the current in the
main exterior circuit, I have also utilized the energy otherwise necessarily lost (in
effecting said demagnetization and increase of potency) for the production of a
current in a subsidiary circuit, which is capable of doing useful work. I have
also discovered that tho currents so as above, either lost by discharge through the
short wire Z or utilized by prolonging said wire to form a subsidiary exterior
circuit, can also be utilized for the reinforcement of the field magnets.
This utilization can be accomplished by prolonging said discharging wire Z to an
extent necessary to coil it about the central spools of the field, making it, of course,
continuous from one of the short segments through both coils back to the other
short segment. It is obviously to be understood that when I am utilizing these
armature currents for the reinforcement of the field magnets, I cannot employ them
for the setting up of a current through a subsidiary circuit capable of running
lights as above set forth. Assume now that I desire to set up currents in two
exterior circuits for the running, for instance, of two separate sets of lamps, I first
couple one extremity of an insulated wire with one of the circuit binding posts
communicating with one major segment of one set of the major segments of tho
commutator, or connect it with said segment direct,-carry such wire in coils
around the two outside spools of one field magnet in succession,-then carry said
wire off through one exterior circuit provided with lamps, p, p, such, for instance,
as I have designated by No: 1 in Figure 3,-carry it back again to the two outside
spools of the opposite field magnet and wind it in opposite succession around said
spools, and finally connect the extremity beyond the last spool to the circuit
binding post which communicates with that other major segment which is the
opposite neighbor in the same set to that major segment to which the first end of
said wire has been attached as described, or with said segment direct. I next
couple one extremity of an insulated wire with one of the circuit binding posts
communicating with one of the major segments of the other set (not being that set
to which the wire of the circuit above described was attached) or connect it with
Baid segment direct,-carry said wire in coils around the central spool of one
field magnet, then carry the wire off through an exterior circuit provided, for
instance, with incandescent lamps gq as designated by No: 2 in Figure 3,-carry
it back again to the central spool of the opposite field magnet and wind it in an
opposite direction around said spool, and connect the extremity beyond the coil
last mentioned to that circuit binding post which communicates with that major
segment which is the opposite neighbor in the same set with that major segment to
which the first end of the wire has been attached as described, or with said segment

page_text: direct. When the apparatus is set up for two main circuits as above described, the
arrangement of the wires of said circuits with respect to their connection with the
sets of major segments can be understood by supposing that, the wire of, for
instance, the circuit No: 1 of Figure 3 is connected with that set of major
segments which are designated by the letter W in Figure 14, and the wire forming
the circuit No: 2 connected with that set of major segments designated by the
letter W¹ in the same figure. It is proper for me here to observe that, while that
precise arrangement of the wires with respect to the spools of the field magnets
above described is that arrangement which will produce the best practical results,
yet that it would be quite possible to vary the arrangement of said wires upon the
spools and, instead of coupling and coiling them precisely in the manner above
-described, couple-the-wire-of-the-circuit No:2, for instance, upon opposite end
spools rather than upon centre spools of the field magnet, and couple the wire of
circuit No: 1 upon adjacent opposite spools rather than upon alternate. It is
proper also for me to observe that if the length of the pole pieces be such as to fit
them to carry a double set of cores, so that instead of the employment of six helices
twelve can be employed, by increasing the number of sets of segments in the
commutator and using three or four pairs of major segments instead of two, moro
than two circuits can be formned; but that, unless the armature be increased in
dimensions and provided with a greater number of pairs of bobbins, the potency of
a greater number of main currents than two would not be proportionately equal to
the potency of the two currents obtained by the precise construction and arrange-
ment of parts illustrated and above described. Assuming now again that I desire
to set up a main current in but a single exterior circuit for the running, for
instance, of arc lamps, but desire to utilize the other main current which I am
enabled as hereinbefore explained to obtain, and which I have designated by No: 2
and illustrated in Figure 3, for the reinforcement of the field magnets-I couple
the wire of said circuit No: 2 in a manner illustrated in Figure 4, that is to say,
carry it in coils around the central spools of the two field magnets and instead of
prolonging it off from the apparatus for the running, for instance, of a set of lights,
simply carry it across the casing so that the current is employed simply for the
magnetization of the field magnets and not for the doing of other work. This
arrangement of wires enables the formation of a reinforcing circuit which I have
designated as No: 3 in Figure 4. It is, of course, to be understood that all of the
armature currents are alike directed to the energizing of the field magnets and to
the consequent formation and subsequent intensifying of whatever currents, main
and subsidiary, are being taken off the machine.
When employ the machine to produce but a single main current the wire
carrying which is coiled and arranged in the manner which I have first among the
several systems of coupling described, a connection for such of the pairs of roller
contacts of the armature as tread upon that set of major segments to which the
wire of the said main circuit is not connected, is, as herein before fully explained,
to be unde from the set of major segments so trodden upon out to either the other
set of major segments or to the wire of the main circuit, as otherwise the pairs of
bobbins referred to would be inert. It will be understood that whether the
machine is coupled to produce one or two main or field currents, it is always
possible to produce the subsidiary current which I have entitled No: 4 and already
fully described, and to utilize it either for the doing of work on a prolonged
exterior circuit not being a field circuit or for the reinforcement of the magnetic
fields. It is proper also for me to state that while I have described the minor
segments as common to both sets of major segments and as serving to receive the
discharge from all the roller contacts of all the sets of armature coils, it is competent
for me to divide the minor segments diametrically into two sets so as to enable the
taking off of two subsidiary currents, a suitable connection analogous to that single
and separate connection by wire herein before described being of course made for
the second subsidiary circuit. Having now described, completely as I believe, the
construction and operation of my apparatus, it is in point for me to state that

page_text: many mechanical changes in the several operativo parts of my apparatus can be
made without departing from the essential features of construction which
characterize the several parts themselves. Thus in Figures 18 and 19 I have
represented a modified form of commutator in which the tread of the roller
contacts or brushes of the bobbin terminals is upon the face or end of a disc-shaped
commutator instead of upon the sides of a cylindric commutator, in which disc-
shaped commutator, however, my construction of major and minor segments and
connection of minor segments is retained and simply modified as to the relative
position and arrangement of said segments. It would be quite competent for me,
moreover, to so further. modify the commutator that certain of the bobbin terminals
should tread upon its end or face in the manner of the above figures, and certain
other sets tread upon its side in the manner previously described. These and
many other kindred changes will be obvious to electricians and do not, as I view
it, require further elaboration by me, as the gist of my invention resides not only
in the mechanical principles of the several constructions herein before explained, by
which constructions I am enabled to derive and utilize several separate currents
from the same machine, but also and vitally resides in the fact that I, for the first
time in the history of the art, have derived from a single bi-polar dynamo-electric
machine, both separate and distinct exterior currents utilized either for the
operating of different lamp circuits or for the doing of other work, or else utilized,
in connection with said operation or doing of work, for the reinforcement of the
fields, and together with said field currents armature currents not being carried off
through the field but discharged through the wire off a subsidiary circuit with
results herein before described. Having thus described my invention, I claim and
desire to secure by Letters Patent :-
1. In a dynamo-electric machine, the combination with a fixed commutator
composed of minor segments electrically connected together and of major segments
to which the wires of field circuits are connected, of a revolving armature
composed of the following elements, to wit:-a series of bobbin spools assembled
in cylindriform relationship, a series of coils forming armature bobbins and being
composed of wires wound upon said bobbin spools, and a series of bobbin terminals,
contacts, or brushes, to which the terminal extremities of the wires of said coils are
connected, substantially as herein before set forth.
2. In a dynamo electric machine, the combination with a fixed commutator
composed of minor segments electrically connected together and of major segments
to which the wires of field circuits are connected,-of a revolving armature con-
sisting of the following clements, to wit:-first, a series of bobbin spools assembled
in cylindriforin relationship, second, a series of coils forming armature bobbins and
being composed of wires wound upon said bobbin spools, third, a series of bobbin
terminals, contacts, or brushes, to which the terminal extremities of the wires of
said coils are connected, and, fourth, a head plate or equivalent contrivance for
carrying and insulating the bobbin terminals, formed of or provided with insulating
material, and adapted to rotate in fixed connection with the spools,―substantially
as set forth.
3. In a bi polar dynamo electric machine the combination of two oppositely
placed semi-cylindric or segmental pole pieces of soft iron each provided as to its
exterior surface with three radial cores, with two oppositely placed semi-cylindric
shells of iron which form the casing of the apparatus are concentric with the pole
pieces and to which said pole pieces are connected and supported through the
instrumentality of their cores, substantially as and for the purposes set forth.
4.--In a dynamo-electric machine, a fixed commutator composed of minor segments
electrically connected together and of major segments to which the wires of field
circuits are connected, substantially as described.
5. In a dynamo-electric machine, the combination with a fixed commutator
composed of minor segments electrically connected together and of major segments
to which the wires of field circuits are connected,-of two field magnets provided
with semi-cylindric magnetic pole pieces set so as to leave between. their adjacent.

page_text: sides open spaces which constitute the neutral zone of the machine,-the arrange-
ment being such that the minor segments in the set up of the machine register
within the area of the neutral zone while the major segments register within the
area of influence of the field magnets, substantially as hereinbefore set forth.
6. In a dynamo-electric machine, the combination with a fixed commutator
composed of ininor segments electrically connected together and of inajor segments
to which the wires of a field circuit are connected, of a revolving armature
composed of a series of separate coils suitably connected for the formation of
separate armature or interior circuits, the terminal extremities of which coils are
connected with bobbin terminals, contacts, or brushes, adapted to revolve with the
armature and in contact with both the major and minor segments of the commutator,
substantially as and for the purposes herein before set forth.
7. In a dynamo-electric machine, the combination with a fixed commutator
composed of minor segments electrically connected, and of sets of major segments
assembled together with the minor segments in suitable relationship, preferably
cylindriform, and as to the respective sets separately connected with the terminal
extremities of the wires of separate field circuits, of a revolving armature
composed of a series of separate coils suitably connected for the formation of
separate armature or interior circuits, the terminal extremities of which coils are
connected with bobbin terminals, contacts, or brushes, adapted to revolve with the
armature, and so respectively disposed as to travel in opposite pairs upon different
sets of major seginents and upon the minor segments of the commutator,
substantially as and for the purposes hereinbefore set forth.
8. In a dynamo-electric machine, a fixed commutator composed of minor segments
electrically connected by a wire of any desired length to form an exterior circuit
not being a field circuit but being employed for useful work, and of sets of major
segments electrically connected with the terminal extremities of the wires of
separate exterior field circuits and assembled in suitable relationship, preferably
cylindriform, with the minor segments,-in combination with a revolving armature
in which are disposed the wires of separate armaturo or interior circuits the
terminals of which revolve with the armature in separate pairs connected with
separate armature circuits and in-contact by sets with both the different sets of
major segments, and with the minor segments of the commutator, all substantially
as and for the purposes herein before set forth.
9. In a dynamo-electric machine, the combination with a fixed commutator
composed of minor segments electrically connected together and of major segments
to which the wires of field circuits are connected, of an armature composed of a
series of bobbins, the terminals, contacts, or brushes, of which revolve fixedly with
said bobbins and are controlled by springs or kindred cushioning devices to
tread upon both the major and minor segments of the fixed commutator,
substantially as set forth.
10. In a dynamo electric machine, the following instrumentalities in com-
bination two oppositely placed field magnets the pole pieces of which aro
semi-cylindric; a fixed commutator composed of two seginents electrically con-
nected by a wire of any desired length, and of two segments insulated from the
two first named but electrically connected by a wire forming a circuit of the field
magnets; a cylindriform armature revolving within the pole pieces of the field
magnets and provided with coils forming the arinature circuits; and a series
of pairs of terminals or contacts for the wires of the armature circuits, each pair
connected with an armature circuit, revolving as a fixed whole with the armature,
and disposed so as to travel in contact with the segments of the commutator, all
substantially as herein before described.
11. The method of demagnetizing the bobbins of a given armature circuit of a
dynamo-electric machine at the moment when said bobbins register within the
area of the neutral zone of the machine, at which moment no current is being
generated in said bobbins by either magnetic field, which consists in bringing the
terminals of said bobbins momentarily in contact with each other through the

page_text: medium of an intermediate electrical connection not being a field circuit and in
discharging the residual magnetism from said armature bobbins through said
electrical connection (the operation taking place successively as to all the bobbins),
whereby not only is the maximum magnetization secured to the bobbins, but a
subsidiary current also set up in snid connection which can be utilized for useful
work, substantially as hereinbefore set forth.
12-In combination with a dynamo-electric machine, a wire the terminals of
which are respectively in opposite major segments of the commutator, which is
carried in coils around the spools of the field magnets, and carried off or prolonged
to form an exterior main or lamp circuit, and a wire the terminals of which are
in the minor segments of the commutator, and which is not connected with
the field magnets, but which constitutes a subsidiary circuit, substantially as set
forth.
13. In a system of producing electrical currents by means of a single bi-polar
dynamo-electric machine,-the combination of one field circuit employed for the
running of lamps or the doing of other work, a second field circuit employed for
the running of a separate series of lumps or the doing of other work, and a third
or subsidiary circuit, employed not only for the demagnetization of the armature
bobbins and for the consequent securing of a maximum energy in all the currents,
but also for the running of a third separate series of lamps or the doing of other
work, all of said circuits having their terminals in said machine.
14. The method of demagnetizing the armature bobbins of a dynamo electric
machine, which consists in passing each of the demagnetizing armature currents in
turn through a circuit connecting such portions of the commutator as are not in
connection with the field circuits.
15. In a system of producing electrical currents by means of a single bi-polar
dynamo-electric machine,-the combination of one field circuit employed for the
running of one series of lamps,--a second field circuit employed for the running of
a separate series of lamps, and a third or subsidiary circuit, not being a field
circuit, employed for the demagnetization of the armature bobbins and for the
consequent securing of a maximum energy in all the currents, all of said circuits
having their terminals in said machine.
16. In a dynamo-electric machine, a fixed commutator composed of minor
segments electrically connected together, and of major segments to which the wires
of field circuits are connected, the said major segments being divided into sots
whereby any desired number of said wires may be connected with the machine.
In testimony whereof I the said Sydney Pitt have hereunto set my hand and
seal this Sixteenth day of June in the year of our Lord 1883.