IMPROVEMENTS IN DYNAMO ELECTRIC MACHINES
Year: 1883

page_text: LETTERS PATENT to William Phillips Thompson of the Liverpool and London
Agency for Foreign Patent Solicitors, 6 Lord Street Liverpool in the county
of Lancaster Civil Engineer for an Invention of "IMPROVEMENTS IN DYNAMO
ELECTRIC MACHINES a communication from Robert. J. Sheehy a person
resident in the city, county, and state of New York, United States of America
"
PROVISIONAL SPECIFICATION left by the said William Phillips Thompson
at the Office of the Commissioners of Patents on the 14th August 1883.
WILLIAM PHILLIPS THOMPSON of the Liverpool and London Agency for Foreign
Patent Solicitors, 6 Lord Street Liverpool in the county of Lancaster, Civil
Engineer, IMPROVEMENTS IN DYNAMO ELECTRIC MACHINES. A communication
froin Robert J. Sheehy, a person resident in the City, County and State of New
York, United States of America.
This invention relates to that class of electrical appliances which have for their
object the conversion of mechanical into electrical energy.
The invention relates in particular to the form and construction of the armatures;
to the disposition of the poles of the field of force magnets; to the method of
applying the power, and to methods of and apparatus for maintaining uniformity
in the strength of current throughout the working circuit.
The main object of this invention is to construct an electric generator of the
dynamo type, which shall as far as practicable, produce a constant electric current
of any required strength with the least possible expenditure of motive power, and
this is accomplished by causing two or more armatures of improved construction,
as bereinafter set forth, to be respectively revolved through fields of force of
constant but opposite polarity, in which armatures two series of electric impulses
are simultaneously induced, the phases of which are so related that when combined,
the resultant is a current of approximately uniform strength.
Further for the purpose of compensating for variations that may occur in the
resistance of the working circuit, devices are applied by which the generating
power of the complete machine may be automatically altered to offset such

page_text: variations of resistance and thus maintain a practically uniform strength of
current.
The invention as related to the armature consists in constructing its core
framework in three circular or ring-shaped sections, one of which is secured to a
revolving shaft and serves as a support for the remaining two, while each of the
latter carries a series of bobbins of insulated wire. The bobbins upon one ring
are arranged with their central portions opposite the spaces intervening between
the corresponding bobbins of the other series. The bobbins themselves however,
are of greater length than the intervening spaces, from which it results that the
extremities of the alternating bobbins overlap or extend beyond each other. By
this construction the amount of inductive wire within the magnetic field is nearly
constant at all times. The armatures made use of are mounted upon a single
shaft which also carries suitable commutators for placing and maintaining the
opposite terminals of the successive bobbins simultaneously in electric connection
with suitable collecting-brushes during the periods of their revolution in which
electric impulses, equal to or exceeding a predetermined strength, are being
induced within them.
As related to the fields of force the invention involves the construction and
disposition of the field magnets with the object of providing for each armature a
magnetic field created by a magnetic force of only one polarity. A constant
-proportion of any armature is at all times within the inductive influence of its
particular field.
Any fluctuations in the strength of the generated current (such as occur when
the resistance of the external circuit is changed) cause corresponding variations in
the magnetic force of the field magnets. These magnetic variations are employed
as a source of power whereby to operate a switch, which shall introduce into or
- withdraw from a-shunt circuit spanning the helices of the field magnets one or
more convolutions of fine wire surrounding said field magnet helices, through which
fine wire the helices of the shunted current passes in such direction as to more or
less demagnetize said field magnets.
The invention also involves the arrangement of two armatures upon one shaft
for the purpose of reducing frcition, and obtaining uniformity of speed,

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Phillips Thompson in the Patent Office on the
13th February 1884.
"
WILLIAM PHILLIPS THOMPSON, of the Liverpool and London Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, in the county of Lancaster, Civil
Engineer " IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES a communication
from Robert J. Sheehy, a person resident in the city, county and state of New
York, United States of America.
This invention relates to that class of electrical appliances which have for their
object the conversion of mechanical into electrical energy.
The invention relates in particular to the form and construction of the armatures;
to the disposition of the poles of the field-of-force magnets; to the method of
applying the power, and to inethods of and apparatus for maintaining uniformity
in the strength of current throughout the working circuit.
The main object of this invention is to construct an electric generator of the
dynamo type, which shall as far as practicable, produce a constant electric current
of any required strength with the least possible expenditure of motive power, and
this is accomplished by causing two or more armatures of improved construction,
as hereinafter set forth, to be respectively revolved through fields of force of
constant but opposite polarity, in which armatures two series of electric impulses
are simultaneously induced, the phases of which are so related that when combined,
the resultant is a current of approximately uniform strength.
Further, for the purposes of compensating for variations that may occur in the
resistance of the working circuit, devices are applied by which the generating
power of the complete machine may be automatically altered to offset such
variations of resistance and thus maintain a practically uniforin strength of current.
The invention as related to the armature consists in constructing its core frame-
work in three circular or ring-shaped sections, one of which is secured to a revolving
shaft and serves as a support for the remaining two, while each of the latter carries
a series of bobbins of insulated wire. The bobbins upon one ring are arranged
with their contral portions opposite the spaces intervening between the corre-
sponding bobbins of the other series. The bobbins themselves however, are of
greater length than the intervening spaces, from which it results that the extremities
of the alternating bobbins overlap or extend beyond each other. By this construc-
tion the amount of inductive wire within the magnetic field is nearly constant at
all times. The arinatures made use of are mounted upon a single shaft, which also
carries suitable commutators for placing and maintaining the opposite terminals of
the successive bobbins simultaneously in electric connection with suitable collecting-
brushes during those portions of their revolution in which electric impulses, equal
to or exceeding a predetermined strength, are being induced within them.
As related to the fields of force, the invention involves the construction and
disposition of the field magnets with the object of providing for each armature a
magnetic field created by a magnetic force of only one polarity. A constant
proportion of any armature is at all times within the inductive influence of its,
particular field.
Any fluctuations in the strength of the generated current (such as occur when
the resistance of the external circuit is changed) cause corresponding variations in
the magnetic force of the field magnets. Theso magnetic variations are employed.
as a source of power whereby to operate a switch, which shall introduce into or,
:

page_text: withdraw from a shunt circuit spanning the helices of the field magnets, one or
more convolutions of fine wire surrounding said field magnet helices, through which
fine wire helices the shunted current passes in such direction as to more or less
demagnetize said field magnets.
The invention also involves the arrangement of two armatures upon one shaft
for the purpose of reducing friction, and obtaining uniformity of speed. The
invention also includes certain details of construction, the exact subject matter
claimed being hereinafter specifically designated.
In the accompanying drawings, Fig. 1 is a side elevation, Fig. 2 an end elevation
and Fig. 3 a plan view of my improved dynamo-electric machine. Fig. 4 shows
the construction of one of the shaft bearings. Figs. 5 and 6 are perspective views
of the core-plates of the armature detached. Fig. 7 shows the circuit connections
of the regulating device.
Referring to the drawings, A and A' represent two similar electro-magnets for
producing the field of force in the generator. The magnet A consists of two
parallel iron cores as a¹ (see Fig. 4) united at their upper extremities with each
other by a horizontal yoke a² of magnetic material. They are each wound with a
series of coils of insulated wire superposed one upon the other in a manner to be
hereinafter described. The electro-magnet A' likewise consists of two similarly
wound cores united by an iron yoke-plate a³. The innermost coils preferably carry
the main current and are all electrically connected together in series, and so that a
current traversing all simultaneously will induce magnetism of one description in
the free extremities of the pole-pieces b' and b, and maguetism of the opposite
description in the corresponding pole-pieces b³ and b*.
The pole-picces are magnetically separated from each other, excepting as they
are connected through the horizontal yoke-plates a' and a³. The pole-pieces b¹ b¹²
bs and cach consists of a block or plate of soft-iron having a semi-cylindrical
rocess formed across one edge, as shown in Figs. 2 and 4. This system of field
magnets is supported from a suitable base B, by means of non-magnetic blocks B¹.
Tho pole-pieces are so arranged that the recessed faces of the pole-pieces b¹ and b
face in one direction and the corresponding faces of the pole-pieces b³ and b* face
in the opposite direction. The two fields thus created are traversed by a central
shaft C supported in two bearings c¹ c¹ formed in standards c³ ³ secured to the
base B.
Armatures D¹ D* are placed respectively in said fields. They are mounted upon
the shaft C in the manner shown in the figure.
It will be observed, from the construction and arrangement of the pole-pieces
and armature shaft that, at any given time, approximately one-half of one entire
armature will be within its field of force, and that at the same time the
diametrically opposite half of the other armature will be in its field. The main
purpose of this construction is to equalize the strain upon the shaft-bearings.
The current generated in the main circuit is the resultant or sum of the successive
impulses induced in the coils of the armatures during their revolution from certain
predetermined points in the field of force to certain other points approximately
half a revolution beyond. A current however, made up of a succession of impulses
of gradually increasing intensity would not itself be of uniform strength, but
varying or fluctuating in its intensity. To obviate this difficulty I employ in each
armature two series of coils, the individual coils of each series alternating with
each other in such manner that the variations in the strength of the impulses
proceeding from one series will be approximately counterbalanced by the
variations in the strengths of the currents or impulses proceeding from the
other series.
The plan of constructing an armature whereby this end may be attained, is as
follows-The core of each armature is formed in three sections, a central and two
outer sections. The central section F (see Fig. 5) is attached directly to the shaft,
and acts as a support for the two outer sections. The section F consists of an
angular casting or disc of soft iron, having two annular series of lugs ƒ and f

page_text: formed upon each of its faces. The lugs and f¹ upon one face alternato in
angular position with those upon the other face, thus each of the lugs upon the
left hand face project from points opposite the central point between the two
corresponding lugs upon the right hand face of the disc. Upon each lug ƒ and ƒ¹
is formed a shoulder f and f³ respectively. Within the inner annular series of
lugs there is formed upon each face of the disc F a continuous annular hub ƒ^
through which are formed openings f³, to allow the passage of the armature
conductors on their way to the commutators.
The remaining discs are similar to each other in construction. Each is composed
of a plate e designed to fit in the recesses between the lugs and f¹ of the central
disc F and to rest upon the shoulders f and f³. The annular plate e is provided
with extension blocks e upon its inner face intended to occupy the spaces between
said shoulders. It is further provided upon its outer face with a number of
radial lugs & designed to fit upon the lugs fand f¹ to which they are secured by
rivets or screws.
Through each lug e¹ are formed three bolt holes et. One of these bolt holes is
located near the outer extremity of the lug, a second near the inner edge of the
lug, and the third at an intermediate point and preferably extending through the
central lug e. By means of suitable bolts extending through these holes and
corresponding bolt holes f formed through the central core-section F, the three
sections of the armature are securely fastened together, with the lugs and
corresponding depressions or recesses interlocking in their proper positions.
The conductors forming the independent bobbins d' d² etcetera are wound upon
such portions of the annular plate as are included between two adjacent systems
of radial lugs.
'
Each bobbin d of the armatures D and D¹ consists of a coil of insulated wire
wound in the ordinary manner and all in the same direction about the flat ringe.
The outer terminal of each bobbin d is connected with an insulating segment of a
commutator G upon one side of the armature, and the inner terminals of the same
are respectively connected with the insulated segments of a second commutator H
upon the opposite side of the armature. In like manner the inner and outer
terminals. of the bobbins comprised in the armature D' are respectively connected
with the segments of the commutators G' and H' located one on each side of that
armature. Each of the four commutators G G¹ H and H¹ consists of eight
segmental rings I' I² 1³ etcetera, and each ring comprises two nearly semi-circular
segments and i. The adjacent ends of each pair i and of segments aro
insulated from each other, and the segmental rings are also insulated from each
other. The commutators are mounted upon the shaft C in the usual manner and
revolve therewith but are insulated therefrom. Collecting brushes K' K* K³ K*
press against the surfaces of the commutators respectively. The segments are
brought successively into contact with these brushes as the shaft rotates. The
arrangement of the commutator segments with reference to their respective
bobbins is such that the respective outer and inner terminals of the successive
bobbins are simultaneously brought into contact with the corresponding brushes in
regular rotation. Thus the outer terminal of the bobbin d' of the armature D is
connected with the segment i¹ of the segmental ring I of commutator G, and its
inner terminal is connected with the segment of the ring I' of commutator H;
the respective terminals of the bobbin d², which is the succeeding and alternate
bobbin, are connected in the same manner with the segments i of ring I', the
terminals of the next succeeding and alternate bobbin d³ with the segments i¹ of
ring 1', etcetera. Half of the coils of a single armature are in this manner
connected to the segments . The remaining half are in the same manner
connected with the segments i.
The conductors leading from the armature coils to the segments are passed
through longitudinal perforations n (Fig. 4) in the insulating sleeve N, preferably
made of compressed paper. This sleeve is contained within a metallic shell k, the
surface of which revolves in the bearings c' supported by standards cª c³. -

page_text: The angular positions of the commutator-segments of the several segmental
rings II etcetera, are such that they are brought in regular succession into
contact with the commutator brush, and immediately upon or before the arrival
of one of the bobbins at the point in the magnetic field where a current generated
therein ceases to be of available strength, the commutator seginents to which the
terminals of said bobbin are connected sever their connections with their respective
brushes.
The contact brushes of the commutator are carried by movable brush holders
capable of angular adjustment in the support . The brush K¹ is preferably
connected to one terminal of the external or work circuit 1 in which the electric
lights or other translating devices are included. The opposite terminal of the
work circuit is. connected to the series of innermost coils O. The circuit passes
thence to brush K' touching at the fulcrum P of the switch P. The contact-
brushes K and K³ are connected directly with each other by conductor 2.
The devices for altering the generating capacity of the machine to offset or
compensate for variations in the resistance of the external circuit may be described
as follows:-
As before stated the cores of the magnets are surrounded each by a series of
coils. The arrangement of coils upon each core is the same. It will therefore
suffice to describe the equipment of a single core.
'
Referring to Figs. 1 and 7; O is a coil of heavy wire through which- the main
current flows. All the main coils such as O are connected in series and when
traversed by the main current develop the poles as already described. Surrounding
the coil O are a number of coils of finer wire o¹ o' o³ o. All the coils o¹ are
connected together in series, likewise with the coils o etcetera. The main circuit,
the course of which has already been described, touches at the point P. This
point is the fulcrum of a switch P¹ which is turned about said fulcrum by
mechanism to be hereinafter described. Q Q Q Q' are contact-points touched
successively by said switch in turning upon said fulcrum. From the point R¹ on
the main line a conductor leads to one terminal of the coil o' and the other
terminal of said coil is connected to the contact point Q. From thence &
conductor R leads to one terminal of the coil of the other terminal of which is
connected to the contact point Q. From thence a conductor R³ connects with
coils o and so on.
S is a rectangular piece of soft iron fastened securely to the pole-piece b³. It
will accordingly exhibit variations of magnetism correlative to the variations in
the strength of the current traversing the main line. By means of these variations
the rovolution of a shaft T is caused in the following manner:
The shaft T is capable of revolving in the bearings U₁ and U₁ between which it
carries a series of small armature levers V1 V2 etcetera severally provided with soft
iron armature-pieces W¹ W₁ etcetera. These levers are loosely arbored upon the
shaft T. Fixed brackets X1 X2 etcetera are securely attached to said shaft by
binding screws Y Y' etcetera, and are arranged spirally upon the shaft. These
brackets serve to communicate at times the motion of said shaft to the armature
levers V¹ V et cetera. The pole piece S is preferably plated with some non-
magnetic metal, in order to prevent the excessive adhesion of the armatures
'thereto.
At the end of the shaft T is a bevelled gear-wheel T', which works in the teeth
of the toothed segment T* carried by the switch P.'.
The manner of operation is as follows: The pole-piece S being magnetized will
exert a strong attraction for the armature-piece W₁, while owing to the spiral
arrangement of the brackets its attraction for the armature-piece W³ will be
somewhat less and that for the armature piece W³ still less, et cetera. Assuming
the attractive force to be sufficient it will cause the revolution of the shaft Tin
opposition to the force of a spring Z, one end of which is connected to the shaft T,
the other end being attached to the bearing U'. By virtue of this attraction the

page_text: shaft will now revolve sufficiently to bring the armature W' into contact with the
pole-piece S, while the armatures W³ and W³ etcetera, will correspondingly approach
toward said pole-piece. If the magnetic force be still further increased, the
armature W will be drawn to the pole-piece, thereby further rotating the shaft
and causing the bracket X¹ to leave the armature W₁ in contact with the pole-
piece S. The shaft T is in this manner made to revolve through the successive
parts of a single revolution, the are of its revolution being dependent upon the
degree of magnetism developed in the pole-piece S. The effect upon the switch P¹
will be to move it successively into contact with the contact-points Q'Q' et cetera,
any convenient number of which may be used, corresponding to the number of
coils o.
When in connection with the point Q a fraction of the main current will
traverse the coils o³, but owing to the manner of winding it will circulate in a
direction opposite to that of the main current circulating in the coils O. The effect
of this opposing current is to undo as it were the magnetism developed by the.
main current. If the switch P¹ be moved into contact with the contact point Q' a
portion of the current will circulate through the coils o' and o² and the opposing
action will be increased. Thus it will be understood that the greater the force of
magnetism developed in the pole-piece S the more will the shaft T be rotated and
the greater will be the number of opposing coils o traversed by the current. Thus
the tendency is created by increases of current to reduce the force of the magnetic
field.
It is evident that the pole-piece S need not necessarily be connected to the field
magnet pole-piece but may be separately magnetized by any suitable helix placed
in the ninin circuit.
Instead of employing only two armatures D and D', any desired number may
be carried upon the same shaft C and constitute one generator, the requisite
number of field magnets and commutators being also provided.
The neutralizing coils o¹ o etcetera while shown in multiple arc or parallel
circuit with the conductors of the main magnetizing helices, are connected in series
with each other as fast as they are introduced. If found desirable however the
neutralizing coils inay be so connected as to operate in multiple arc with each other
instead of in series. The plan to be adopted in any case will depend largely upon
the character of the current generated.
F
Having thus described the invention and the manner in which it is to be
performed as communicated to me by my foreign correspondent, I would have it
understood that what I claim and desire to protect under the Letters Patent is :-
1st. The combination, substantially as hereinbefore set forth, of a central
armature plate or disc of soft-iron and an annulus of soft-iron carried thereby by
suitable projections, and situated in a plano parallel to the plane of said central
plate.
2nd. The combination, substantially as herein before set forth, of a central
armature disc or plate of soft-iron, two annuli of soft iron, one on either side of
said disc, and means of attaching said annuli to the face of said disc, substantially
as described.
3rd. The combination, substantially as herein before set forth, of the central
armature disc, upon each face thereof an annulus of soft iron, means of attachment
substantially as described, and coils of conductors surrounding each annulus except
at the points of attachment.
4th. The combination, substantially as hereinbefore set forth, of a central
shaft, a disc of soft iron carried thereby situated in a transverse plane thereto, an
annulus of soft iron carried upon the face of said disc, shouldered lugs projecting
from said disc, lugs projecting from said annulus for fitting said shouldered lugs,
and bolts for securing them in place.
5th. The combination, substantially as herein before set forth, of a central disc of
soft iron, two series of bobbins one on either side thereof, the bobbins of one series
being placed in intermediate angular positions to those of the other series, and said

page_text: bobbins lying lengthwise in a plane parallel to the plane of said disc, substantially
as described.
6th. The combination, substantially as hereinbefore set forth, of two field magnets
having their respective parts parallel the one to the other, two semi-circular fields
arranged in the same axial line, produced by said magnets in the manner described
and facing in opposite directions.
7th. The combination, substantially as hereinbefore set forth, of two independent
magnetic fields arranged in the same axial line, one produced by two semi-circular
pole-pieces of similar polarity, and the other by the remaining pole-pieces of the
electro-magnets producing said first mentioned field.
8th. The combination, substantially as hereinbefore set forth, of two fields, one
produced by two semi-circular pole-pieces of similar polarity, and the other
produced by the remaining pole-pieces of the electro magnets producing said field
first mentioned, a single shaft traversing both fields, and two armatures mounted
on said shaft and having equal and diametrically opposite section; respectively
situated in said fields at the same time..
9th. The combination, substantially as hereinbefore set forth, of two magnetic
fields respectively created by the pole-pieces having similar polarity, of two
independent electro-magnets, two armatures having diametrically opposite sections
of coils respectively traversing said fields simultaneously, and the four commutators
described for collecting the currents generated in said armatures.
10th. The combination, substantially as herein before set forth, of two fields
created and disposed in the manner described, two armatures revolving in said
fields, a single shaft upon which said armatures are mounted, and a central pulley
by which said shaft is impelled.
11th. The combination, substantially as hereinbefore set forth, of a main
magnetizing helix, a. secondary helix surrounding said inain magnetizing helix, and
means for causing the current to traverse more or less of said secondary helix in a
reverse direction to the current traversing said main magnetizing helix, for the
purpose of modifying the generative action of said generator.
12th. The combination, substantially as herein before set forth, of the field
magnet of a dynamo-electric machine, a main magnetizing helix therefor, one
or more secondary helices surrounding said main magnetizing helix, and mechanisin
for introducing said secondary helices into and withdrawing them from a
shunt circuit spanning said main magnetizing helix for the purpose of varying
its effects.
13th. The combination, substantially as hereinbefore set forth, of the main
'magnetizing helix of the field magnet of a dynamo electric machine, one or
more secondary helices surrounding said main magnetizing helix, and switch
mechanism for introducing said secondary helices successively into a shunt
circuit spanning said main magnetizing helix and wound in the roverse direction
thereto.
14th. The combination, substantially as hereinbefore set forth, of a main
magnetizing helix of the field magnet of a dynamo-electric machine, differentially
wound conductors surrounding said main magnetizing helix, and mechanism
substantially such as described for automatically varying the length of said
conductors correlatively with variations in the strength of current generated.
15th. The combination, substantially as herein before set forth, of a main
magnetizing helix of a dynamo-electric machine, a series of opposing helices, a
switch for including said helices in a shunt circuit spanning said main magnetizing
helix, and a device operated by variations in the electro-magnetism produced by
the main current for operating said switch.
16th. The combination, substantially as herein before set forth, of a main
'magnetizing helix of the field magnet of a dynamo-electric machine the helices of
which are included in the main circuit, a shaft revolved by the attraction of a
magnet for a series of armatures, a switch operated with changes in the angular

page_text: position of said shaft, and differential helices introduced into and withdrawn from
a shunt circuit spanning said main magnetizing helix according to the position of
said switch.
In witness whereof I the said William Phillips Thompson have hereunto set my
hand and scal this eleventh day of February in the year of our Lord one thousand
eight hundred and eighty four.
WM P. THOMPSON (L.S.)