Year: 1897

page_text: ALBERT W. SMITH, 481, Missouri Avenue, Washington, D.C., U.S.A., Electrical
Engineer, do hereby declare the nature of this invention to be as follows:-
The general object is to produce an electrical generator or motor having a greatly
increased out put or effectiveness per unit of weight over that obtained in present
practice, also having a greater electrical efficiency, and entire freedom from shifting
of the neutral or commutating points, and the sparking, overheating, and faulty
regulation resulting therefrom.
To these ends the invention consists in so constructing the field magnets, and in
so winding the field-magnet coils that the angular shifting of the neutral or com-
mutating points, caused by field distortion, due to the magnetic reaction of the
armature currents is entirely prevented, thus eliminating the necessity for a wide
so called neutral, (really a field shifting space).
The armature coils occupying this wide neutral or field shifting space do not
produce any useful effect, but, on the contrary, they consume energy and
produce heat, and they also contribute greatly to the field distortion, and the con-
sequent sparking, overheating and faulty regulation, thus tending only to limit the
out put of the machine, and to reduce its electrical efficiency and general reliability.
It is obvious that the elimination of these worse than idle armature coils will greatly
increase the possible out-put of the machine, as well as its electrical efficiency.
The above described results are obtained by the employment of a field magnet of
peculiar form, which permits of winding the field magnet coils contiguous to the
armature, and entirely on that side of the neutral or cominutating points on which
the armature coils have a current opposite in direction to the current in those
parts or laps of the field coils which lie contiguous to the armature.
In the drawings herewith,
Fig. 1 is a front view of my invention. Figs. 2, 3, 4 and 5 are modifications
thereof. In all the views the saine letters refer to like or corresponding parts.
a a are field magnets each having a neutral gap b, and at one side thereof a
plurality of poles cc c, forming between them coil spaces d, while at the other side
of gap 6 they have a single wide pole c', ee are field magnetizing coils, each wound
in four sections as shown through spaces d d, and connected to form a single coil for
each magnet as shown.
One of the coils e is shown fully wound, while the others are shown by a single
turn wound through each coil space d. f is the armature wound with coils g,

page_text: connected to segments h h as shown. The commutator is cross connected, as shown,
thus requiring but two brushes h¹ and h2. The endless dotted lines it, and the
arrows forming part thereof show the form and direction of the magnetic fields.
jjare small electro magnets wound with coils kk, and placed in gaps b b at points
coinciding with neutral lines ll.
The fields m of magnets j have the direction shown by arrows on magnets j, and
they surround, interlink with, or embrace, but do not intercept, cut, or cross those
of the coils y which are for the time being in the neutral or cominutating positions.
The direction of current flow in all the coils is as shown by arrow heads thereon.
The arrow n shows the direction of rotation.
The field coils e are entirely back of the neutral lines of thier respective
magnets, and are therefore situated contiguous to those of the armature windings
having current of opposite direction in the air gap to that in the field coils.
The armature current sets up magneto motive forces represented by arrows pp, which
tend to distort the field magnetism in a forward direction, thus diverting the field
magnetism from the general magnetic axis of coils e e, and causing the magnetism to
flow through the plural poles cc, and also causing some of the magnetism to leak
across each section of coils e e, as shown by the fluid shading 7 q, the magnetism
of the coil sections can not, however, he distorted further forward than the point
indicated by its corresponding dotted line r, for obviously, the magnetism could not
exist without passing through some portion of its generating coil or section.
In Fig. 2 is shown a form of field magnet for reversible machines. The magnets a
have plural poles e on each side of gap b. If the armature is turned as per arrow n
on the right, the coils e and e are used, while if the armature is rotated as per
arrow on the left, the coils el el are used.
In Fig. 3 is shown a modification of magnet a having each a single coil space d, in
which are wound the coils e.
In Fig. 4 is shown a modification of of magnet having no neutral gap b, but
a single wide coil space d extending from line to the end of the magnet.
In Fig. 5 magnet a has plural poles con each side of gap b. Those on the right
are wound with a coil e as in Fig. 1, while those on the left are wound with a coil e¹,
with the return laps wound through gap b.
ALDENT W
CMITLL
Improvements in Dynamos and motors.
I, ALBERT W. SMITH, of 481, Missouri Avenue, Washington, D.C., U.S.A., 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 :-
The object of this invention is to reduce or limit field distortion, so that the
brushes may remaid in a fixed position for all conditions of load.
Also to prevent
the sparking at the brushes which is due to self-induction in the armature coils at the
moment of current, reversal therein, and while the current is increasing from zero to
its full value.
In the drawings filed with my Provisional Specification Fig. 1 is a front view of a
machine embodying my invention, Figs. 2, 3, 4, and 5 illustrate modifications
thereof.
a a are field magnets each having a neutral gap b. and at one side thereof a
plurality of poles c c forming between them coil spaces d, while at the other side of
gap 6 they have a single wide pole c¹. e e are field magnetizing coils each wound in

page_text: four sections as shown, through spaces d d and connected to form a single coil for
each magnet as shown.
One of the coils e is shown fully wound, while the others are shown by a single turn
wound through each coil space d. f is the armature wound with coils g, connected
to segments has shown. The coininutator is cross connected as shown, thus requiring
but two brushes h¹ and h².
The endless dotted lines ii and the arrows forming part thereof show the form and
direction of the magnetic fields. jj are small electro magnets wound with coils k k
and placed in gaps bat points coinciding with the neutral lines ll.
The fields m of magnets j have the direction shown by arrows on magnets j, and
they surround, interlink with, or embrace, but do not intercept, cut or cross those of
the coils g which are for the time being in the neutral or commutating positions.
The direction of current flow in all the coils is shown by arrow heads thereon. The
arrow n shows the direction of rotation.
The field coils e are entirely back of the neutral lines of thier respective magnets,
and are therefore situated contiguous to those of the armature windings having
current of opposite direction in the air gap to that in the field coils.
The armature sets up magneto motive forces represented by arrows p, which tend
to distort the field magnetism in a forward direction, thus diverting the field
magnetism froin the general magnetic axis of coils e e, and causing the magnetism
to flow through the plural poles c c, and also causing some of the magnetism_to
leak across each section of coils e as shown by the fluid shading 9 9. The
magnetism of any of the coil sections can not, however, be distorted further forward
than the point indicated by its coresponding dotted line r, for obviously, the
magnetism could not exist without passing through some portion of its generating
coil or section. It is therefore evident that no matter how great the armature
current and its reactive tendency may be, the neutral lines can not be shifted, and
therefore the points of commutating will remain constant under all conditions of
load.
It is also obvious that the width of the neutral space may be limited to a
mere point, thus eliminating the inactive armature coils, and thereby enhancing
the out-put and efficiency of the machine. When little or no current is flowing
in the armature the field magnetism tends to follow the general magnetic axis of
coils e e, that is, it tends to flow through all of the sections composing a coil e,
since however the cross section and therefore the carrying capacity of the magnets
a gradually decreases towards thier rear ends, and also, as the plural poles c form
leakage paths of low reluctance to the armature, the magnetism very naturally
prefers these leakage paths; thus there may be said to exist a prior, antecedent,
and self constituted distortion between coils e and thier field, that is to say,
the distortion in a measure exists independently of and anticipates the armature
reaction.
In the present practice of dynamo design the self-induction in the armature coils at
the moment of current reversal is neutralized or counteracted by subjecting the coils
at this moment to an opposing dynamic induction, that is, an induction produced by
the mechanical movement of the coil across the field. This is usually accomplished
by shifting the brushes forward to positions where they will cut, cross, or
intercept the required strength of field. The method employed by me differs
radically from the foregoing, inasmuch as the self-induction is neither neutralized
nor counteracted by dynamic induction, but is entirely prevented by surrounding,
or interlinking those of the coils which coincide with the lines l, and at the
moment of current reversal therein, with the magnetic fields m produced by
magnets j. At the moment of current reversal, and during the time that the current
is increasing from zero to its full value the coils tend to set up local fields having the
direction shown by arrows p. The fields m have, as shown by arrows on magnets j
a contrary direction to the magneto motive forces represented by arrows p. It is
therefore obvious that if the fields m are equal or superior in strength to those
which coils g tend to set up, then no self-induction can possibly take place, for

page_text: the existance of self-induction in a coil depends on the presence of a self
generated magnetic flux surrounding the same, and my invention consists in
preventing this flux by one of contrary direction. It is obviously not absolutely
necessary that the fields m be equal or superior in strength to those which
coils tend to set up, but may be slightly weaker, for evidently, a small amount
of self induction will not cause sparking. It is preferable however, to have the
This
fields m exactly equal in strength to those which coils y tend to set up.
result is obtained by placing on magnets; the same number of ampere turns as are
contained in coils g.
It is assumed that the fields m will not be shifted by the armature reaction, and
that the relationship between them, those of the coils y undergoing reversal, and the
lines will be as shown in Fig. 1. If in practice a shifting of the fields m occurs,
then brushes and must also be shifted accordingly, the essential conditions
being, that the fields m shall surround or interlink with, but not cut or sweep across
the coils y at the moment of current reversal therein.
In Fig. 2 is shown a form of field magnet for reversible machines. The magnets a
have plural poles c on each side of gap b, if the armature is turned as per arrow n
on the right, then the coils e and e are used, while if the armature is rotated as per
arrow on the left the coils e¹ and e¹ are used. This form of magnet and winding
is adapted for railway and hoisting motors, and reversible machines in general.
In Fig. 3 is shown a modification of magnets a having each a single coil space d,
in which are wound the coils e.
In Fig. 4 is shown a modification of magnets a having no neutral gaps b, but a
single wide coil space d extending from line to the end of the magnet, and
wound each with a single coil e. If the machine is supplied with current flowing
as per arrow heads thereon, the armature will turn as per arrow n, when a machine
is used as a motor the armature coils are commutated in the contrary direction to
that in a generator, and the local fields which they tend to set up, are opposed in
It is
direction to the field magnetism i, and no self induction can take place.
therefore in a motor not necessary to use the magnets, but only to so arrange
matters that there will be no neutral gap b in which coils g may set up thier local
fields, when self induction will be entirely prevented by the opposing direction of
the main fields . This is accomplished by winding coils e right up to lines, thus
insuring the absence of a neutral gap b.
In Fig. 5 magnet a has plural poles on each side of gap b, those on the right are
wound with a coil e as in Fig. 1, while those on the left are wound with a coil e,
with the return laps wound through gap
ს.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
1. An improved dynamo or motor, substantially as set forth, illustrated an
described.
2. In an electrical generator or motor, the method of preventing the shifting of
the neutral or commutating points, which method consists in causing the magnetism
of an assymetrically wound field magnetizing coil to be diverted from the general
magnetic axis of said coil, by causing the magnetism generated by the several turns
or sections of said coil to leak out through the sides of said coil, between the several
turns or sections thereof, substantially as set forth.
3. In an electrical generator or motor, the method of preventing the shifting of
the neutral or commutating points, caused by field distortion, due to armature
reaction, which method consists in producing a prior, antecedant and self constituted
distortion between a field magnetizing coil and its field, and thus limiting the amount
of further distortion which may be caused by the armature reaction, substantially as
set forth.
4. In an electrical generator or motor, the method of preventing the shifting o
the neutral or commutating points, which method consists in placing all of those

page_text: laps or portions of the field magnetizing coils which lie contiguous to or near the
armature, in or across the flux path of the magnet, and entirely on those sides of the
neutral or commutating points of the field magnets, on which the armature coils have
currents of opposite direction to the current in the contiguous laps or portions of
the field coils, substantially as set forth.
5. In an electrical generator or motor, a field magnetizing coil having some of
its laps or portions wound contiguous to the armature, said contiguous portions
being wound entirely on that side of the neutral or commutating point of the field
magnet on which the armature coils have currents of opposite direction to the
current in the said contiguous laps or portions of said field coil, substantially as set
forth.
6. In an electrical generator or motor, a field magnet having on one side of its
neutral gap or point a single wide pole, and on the other side of said neutral gap or
point several plural poles, said plural poles forming between them coil containing
spaces, said spaces being contiguous to the armature, substantially as set forth.
7. In an electrical generator or motor, a field magnet having on one side of its
neutral gap or point a single wide pole or polar area, and on the other side of said
neutral gap or point a coil space or spaces, said space or spaces being contiguous
to the armature, substantially as set forth.
8. In an electrical generator or motor, a field magnet having on each side of its
neutral gap or point several plural poles, and two independent sets of energizing
coils wound between said poles, one of said sets of coils being used when the
machine runs in its normal direction, and the other set of said coils being used
when the machine runs in a reversed direction, substantially as set forth.
9. In an electrical generator or motor, a field magnet having on on side of its
neutral gap a single wide pole or polar area, and on the other side thereof a single
pole and a single coil space, in which the energizing coil is wound, substantially as
set forth.
10. In an electrical generator or motor, a field magnet having no neutral gap, and
having at one side of its neutral point a single wide pole, and on the other side a
coil space or spaces, in which the magnetizing coil is wound, substantially as set
forth.
11. In an electrical generator or motor, the method of preventing the existance of
self-induction due to the rise or increase of current in the commutable coils at the
moment of commutation, or when thier respective commutator segments leave or
break contact with the brushes, which method consists in forestalling or anticipating
said self induction in said commutable coils by surrounding, embracing, enveloping,
or interlinking said commutable coils at the moment of commutation with a prior or
antecedent magneto motive force of contrary direction to that which exists or tends
to exist in the commutable coils at the moment of commutation, substantially as set
forth.
12. In an electrical generator or motor, the combination with the commutable
coils thereof, of means for surrounding, embracing, or interlinking said commutable
coils at thier moments of commutation with a magnetic field contrary in direction to
the local magnetic fields which said commutable coils tend to set up at the moment
of commutation, substantially as set forth.
13. In an electrical generator or motor, the combination with the commutable
coils e thereof, of electro magnets h h wound with an equal number of ampere-turns
as are contained in said commutable coils e e, substantially as set forth.
Dated this 13th day of August 1898.