IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES
Year: 1885

page_text: I, ALEXANDER MELVILLE CLARK, of the firm of A. M. and Wm. Clark, of
53, Chancery Lane, in the County of Middlesex, Fellow of the Institute of Patent
Agents, do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
DYNAMO-ELECTRIC MACHINES a communication to me from abroad by Lucien
Vissière, Electrician, of 2 Rue Marengo, Marseilles, France, to be as follows:-
و"
In ordinary electric machines the ratio of the mechanical power absorbed to the
mechanical power utilised is about 90 per cent or nearly the maximum of energy
obtainable; this invention has therefore for its object an economical mode of
construction whereby to utilize under the most favourable conditions, the material
employed and obtain from the mass the maximum effect, regard being had to the
different strains which they have to support.
The invention relates essentially to novel forms and arrangements employed in
the construction of electrical machines and in order that the Invention may be
readily understood, I will proceed to describe it by way of example with reference
to the accompanying drawings as applied to a dynamo-electric machine. Figure 1
represents a central longitudinal vertical section of the entire machine and figure 2
a transverse vertical section of the same. Figure 3 represents a face view of the
armature partly in section to show the details of construction. Figure 4 is a
sectional front elevation of the machine showing the support for the brushes and
the means of automatically regulating their position. Figure 5 is a face view of
the plates of the collecting discs. Figure 6 is a longitudinal vertical section of the
collecting discs. Figure 7 shows a detail of the brushes. Figure 8 is a perspective
view of the machine. Figure 9 shows the machine as applied for the distribution
of power and light by means of a receiving and distributing machine having
two secondary circuits. The type of machine represented comprises six field
magnets A, A, B, B, B, B external of the armature B and so arranged that their
total maximum section calculated as solid, according to the external dimensions of
the faces next to the pole pieces C, shall be as large as possible in proportion to
that of the core of the armature. This arrangement allows of the ends of the field
D

page_text: magnets acting normally instead of laterally upon the armature whereby a better
inductive action is obtained. A field magnet D is placed within the armature to
augment the surface of the poles; the pole pieces C also are made solid.
In order to give the field magnets as large a section as possible, the coils of
the electro-magnets A B are made to project beyond the pole pieces as shown in
figure 1, and said coils E are wound conically upon the cores so as to concentrate
the magnetism towards the poles. In this improved machine, the field electro-
magnets are made hollow and preferably in the form of a truncated rectangular
pyramid as clearly shown in figures 1 and 2, whereby a greater magnetic action is
ensured with an equal weight of metal. The wires employed for the field magnets
are flat or of rectangular section, of little thickness, in order to completely fill the
space reserved for the wire and allow of a very large number of layers being
superposed and thus augmenting the power of the field magnets for an equal
weight of wire of circular section or even rectangular, but less flat. The wire may
however be of different sections upon the same field magnet so as not to exceed
the desired electrical resistance, while still employing a large number of coils.
The cores of the field magnets may be made in several parts, bars of rods of any
section, either built up as in figure A or formed of concentric tubes as in figure B
which represents a field magnet having three cylindrical cores but which may be
of other form. In these several arrangements the wire may be wound either upon
a single core or on several. The wires of the large field magnets are enclosed in a
casing or envelope B either of thin sheet metal or wire ribbon covering the outer
coil of the electro-magnet as shown in order to concentrate the action of the wires
upon the core. The outer field magnets B are fixed to the pole pieces by steel
bolts H previously magnetized or magnetized at the time of first starting the
machine and remaining magnetized in order that sufficient residual magnetism shall
always be retained to rapidly charge at each time of starting, self exciting machines.
With the same object, the bolts H of the large field magnets A are made to pass
through the permanent magnets H'.
The armature, figures 2 and 3 is composed of a ribbed iron cylinder I in which
the induced wire whether of circular or rectangular section or of the bar form
shown at J figure 3, is inserted. In certain cases I employ two collectors K L
figures 5 and 6 of disc form. In machines in which rectangular bars or very coarse
wire are employed, the segments of the collector are inclined as shown at K figure 5
and the wire which makes only one turn around the cylinder is united at each end
to said segments which being of considerable thickness diminish the resistance of
the secondary circuit of which they form part; moreover there is less wire remaining
inactive. In machines in which fine wire is used, the segments of the collector are
straight as at L figure 5 and a little space is left between the collector and the coil
as shown at the lower part of figure 6 to permit of the ready attachment of the
wires to the segments. In either case that is to say whether coarse or fine wire be
employed, the employment of two collectors serves to prolong the wear of the
machine if only one be employed while the machine is working to be assisted by
the other in case of wear, or for effecting more readily the division of the current
by means of brushes suitably arranged in connection with both collectors. These
two collectors are also applicable in machines having several secondary circuits
hereinafter described.
Figure 7 represents the arrangement of brush which I employ in connection with
this improved machine.
The brushes are composed of a roller or cylindrical brush b revolving in contact
with the collector and coupled together two and two so as to bear upon two adjacent
segments for the purpose of reducing friction and wear of the collector and prevent
sparking; the roller b is also provided with rubbers to ensure perfect contact for
the passage of the machine current. c is a spiral spring inserted in the bearing of
roller for maintaining it in constant contact with the collector.
The series of brushes bis carried by a disc M figures 2 and 4 mounted upon one
of the bearings of the machine by four screws N which allow of its turning in a

page_text: groove o in said bearing in which the points of the screws are received. The
movement of disc M is regulated automatically as hereafter described.
The disc M is provided with a series of slots p figure 4 in which the rods of the
brush holders slide, said slots being in number sufficient to admit of an easy division
of the current and also enable various kinds of apparatus requiring different electro-
motive forces and intensities to be connected with the machine, without any
irregularities or variations in the working of any one of said apparatus affecting
the remainder.
Figure C represents such an application of the machine, showing how it is
possible to introduce in or withdraw any one of these apparatus from the circuit
or in the case of lamps to light or extinguish any one of them separately.
The improvement consists in applying on the collector twice as many points of
contact, as there are groups of apparatus in series, and in joining up these contacts
(brushes or rubbers) having the same tension, with groups of corresponding
apparatus, by means of a wire capable of supporting the total intensity of the
current required for this group.
The brush holder in this case consists of hinged or sliding arms to permit of a
suitable adjustment of the contacts in connection with the collector.
The diagram figure C shows the arrangement of the systein in the case of the
following apparatus-d are lamp of 50 volts, e f incandescent lamps of 60 and
90 volts g h electric motors of 150 and 200 volts. These combinations may
evidently be varied indefinitely, care being taken to so arrange the apparatus that
the total intensities in each group, shall be as nearly as possible, equal one to the
other and equal to the intensity which the machine is capable of furnishing in
order to utilise the machine in the best possible conditions, its electro-motive force
being so regulated as to be equal to the total of those required for each group.
The exact position of the brushes upon the collector to suit the variations in the
working of the machine is constantly ensured by means of the automatic-regulator R
figures 2 and 4. This regulator is fixed on one of the machine bearings by a bolt
received in a hole S, which allows of the regulator being oscillated to facilitate its
adjustment according to the direction of motion of the machine. The regulator is
composed of two electro-magnets hi, the first of which is covered with fine wire
and is traversed by a constant current, the wire being in derivation on the poles ;
the second which is in tension or in circuit with the apparatus (lamps &c) receives
the total current produced by the machine and acts differentially with the first
electro-magnet h upon the soft iron rod k placed in its core, so as to adjust to a
greater or less extent the disc M which carries the brushes.
The soft iron rods are fixed to the disc by pins which permit of its free
oscillation (see figure 4). The disc M carries with it the brushes, which thus
always occupy their exact position on the collector; according to the working of
the machine.
This arrangement is intended to prevent the production of sparks and wear of
the collector and brushes and it also ensures a more regular working of the machine.
A single electro-magnet may also be employed with the regulator, the other being
replaced by a weight, spring, or its equivalent.
In machines intended for the transmission of force by means of distributing
receivers, I place upon the armature, two entirely independent circuits of wire,
either arranged in adjacent grooves of the armature-core as represented at TU
figure 3 or superposed in the same grooves as at V. One circuit of fine wire is
the receiving circuit and receives the current from the generator placed at a distance
whereby the rotation of the armature shaft which drives the adjacent transmitting
mechanism is produced.
The second or distributing circuit of coarser wire supplies the necessary current
to the lamps, electrolytic baths or other small electro-motors placed within the
radius of the machine. The object of these arrangements is to economize expense
in the conducting wires and to employ but one machine in cases where a portion of

page_text: the force transmitted is to be converted into electricity: a greater result is in this
manner obtained.
The two circuits may be mounted on the same armature, or upon two coils
mounted upon the same shaft; a single or separate field magnets are used for the
two circuits according to the kind of machine.
The diagram figure 9 shows the application of the distributing receiver m with
two collectors n and bi-circuit armature, combined with a generator o for working
a machine tool p, arc lamp q, incandescence lamps p and electro-motors 8.
As will be seen these machines may be used for lighting and other applications
when it is desired to supply two or more distinct circuits; for example the fine
wire circuit may be used for supplying are lamps grouped in tension and the coarse
wire circuit for supplying incandescent lamps grouped in quantity.
The several improvements hereindescribed may be applied to electric apparatus
generally but more particularly to continuous or alternating current machines with
separate or consequent poles or unipolar. They also permit of giving a higher
velocity to the armatures or moving field magnets, afford considerable advantages
in utilising material, enable machines to be constructed at relatively small cost,
and particularly electric motors of high tension and small dimensions; they also
ensure a smoother working of electric machines operated by motors working
irregularly.

page_text: Improvements in Dynamo-electric Machines.
I, ALEXANDER MELVILLE CLARK, of the firm of A. M. and Wm. Clark, of
53, Chancery Lane, in the County of Middlesex, Fellow of the Institute of Patent
Agents, do hereby declare the nature of this Invention (a communication to me
from abroad by Lucien Vissière, Electrician, of 2, Rue Marengo, Marseilles, France),
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :—
In ordinary electric machines, the electrical efficiency, that is to say, the ratio of
the mechanical power absorbed, to the mechanical power utilized being about
90 per cent, or nearly the maximum of energy obtainable, there is little benefit to
be obtained by increasing this efficiency. This Invention has, therefore, for its
object an economical mode of constructing these machines, whereby to utilize
under the most favorable conditions the material employed, and obtain from the
mass, the maximum efficiency, regard being had to the different strains which
they have to support.
The invention relates essentially to novel forms and arrangements employed in
the construction of electrical machines and in order that the Invention may be
readily understood, I will proceed to describe it by way of example with reference
to the accompanying drawings as applied to a dynamo-electric machine. Figure 1
represents a central longitudinal vertical section of the entire machine and figure 2
a transverse vertical section of the same. Figure 3 represents a face view of the
armature partly in section to show the details of construction. Figure 4 is a
sectional front elevation of the machine showing the support for the brushes and
the means of automatically regulating their position. Figure 5 is a face view of
the plates of the collecting discs. Figure 6 is a longitudinal vertical section of the
collecting discs. Figure 7 shows a detail of the brushes. Figure 8 is a perspective
view of the machine. Figure 9 shows the machine as applied for the distribution
of power and light by means of a receiving and distributing machine having
two secondary circuits. The type of machine represented comprises six field
magnets A, A, B, B, B, B external of the armature ẞ and so arranged that their
total maximum section calculated as solid, according to the external dimensions of
the faces next to the pole pieces C, shall be as large as possible in proportion to
that of the core of the armature. This arrangement allows of the ends of the
field magnets acting normally instead of laterally upon the armature whereby
a better inductive action is obtained. A field magnet D is placed within the
armature to augment the surface of the poles; the pole pieces C also are made
solid.
In order to give the field magnets as large a section as possible, the coils of the
clectro-magnets A B are made to project beyond the pole pieces as shown in
figure 1, and said coils E are wound conically upon the cores so as to concentrate
the magnetism towards the poles. In this improved machine, the field electro-
magnets are made hollow and preferably in the form of a truncated rectangular
pyramid as clearly shown in figures 1 and 2, whereby a greater magnetic action is
ensured with an equal weight of metal. The wires employed for the field magnets

page_text: are flat or of rectangular section, of little thickness, in order to completely fill the
space reserved for the wire and allow of a very large number of layers being
superposed and thus augmenting the power of the field magnets for an equal
weight of wire of circular section or even rectangular, but less flat. The wire may
however be of different sections upon the same field magnet so as not to exceed
the desired electrical resistance, while still employing a large number of coils.
The cores of the field magnets may be made in several parts, bars of rods of any
section, either built up as in figure A or formed of concentric tubes as in figure B
which represents a field magnet having three cylindrical cores but which may be
of other form. In these several arrangements the wire may be wound either upon
a single core or on several. The wires of the large field magnets are enclosed in a
casing or envelope B either of thin sheet metal or wire ribbon covering the outer
coil of the electro-magnet as shown in order to concentrate the action of the wires
upon the core. The outer field magnets B are fixed to the pole pieces by steel
bolts H previously magnetized or magnetized at the time of first starting the
machine and remaining magnetized in order that sufficient residual magnetism
shall always be retained to rapidly charge at each time of starting, self exciting
machines. With the same object, the bolts H of the large field magnets A are
made to pass through the permanent magnets H².
The armature, figures 2 and 3 is composed of a ribbed iron cylinder I in which
the induced wire whether of circular or rectangular section or of the bar form
shown at J figure 3, is inserted. In certain cases I employ two collectors K L
figures 5 and 6 of disc form. In machines in which rectangular bars or very
coarse wire are employed, the segments of the collector are inclined as shown at K
figure 5 and the wire which makes only one turn around the cylinder is united at
each end to said segments which being of considerable thickness diminish the
resistance of the secondary circuit of which they form part; moreover there is less
wire remaining inactive. In machines in which fine wire is used, the segments of
the collector are straight as at L figure 5 and a little space is left between the
collector and the coil as shown at the lower part of figure 6 to permit of the ready
attachment of the wires to the segments. In either case that is to say whether
coarse or fine wire be employed, the employment of two collectors serves to prolong
the wear of the machine if only one be employed while the machine is working to
be assisted by the other in case of wear, or for effecting more readily the division
of the current by means of brushes suitably arranged in connection with both
collectors. These two collectors are also applicable in machines having several
secondary circuits hereinafter described. Figure 7 represents the arrangement of
brush which I employ in connection with this improved machine.
The brushes are composed of a roller or cylindrical brush b revolving in contact
with the collector and coupled together two and two so as to bear upon two
adjacent segments for the purpose of reducing friction and wear of the collector
and prevent sparking; the roller b is also provided with rubbers to ensure perfect
contact for the passage of the machine current. c is a spiral spring inserted in the
bearing of roller b for maintaining it in constant contact with the collector.
The series of brushes bis carried by a disc M figures 2 and 4 mounted upon one
of the bearings of the machine by four screws N which allow of its turning in a
groove o in said bearing in which the points of the screws are received. The
movement of disc M is regulated automatically as hereafter described.
The disc M is provided with a series of slots P figure 4 in which the rods of the
brush holders slide, said slots being in number sufficient to admit of an easy
division of the current and also enable various kinds of apparatus requiring
different electro-motive forces and intensities to be connected with the machine,
without any irregularities or variations in the working of any one of said apparatus
affecting the remainder.
Figure C represents such an application of the machine, showing how it is
possible to introduce in or withdraw any one of these apparatus from the circuit or
in the case of lamps to light or extinguish any one of them separately.

page_text: The improvement consists in applying on the collector twice as many points of
contact, as there are groups of apparatus in series, and in joining up these contacts
(brushes or rubbers) having the same tension, with groups of corresponding
apparatus, by means of a wire capable of supporting the total intensity of the
current required for this group. The brush holder in this case consists of hinged or
sliding arms to permit of a suitable adjustment of the contacts in connection with
the collector.
The diagram figure C shows the arrangement of the system in the case of the
following apparatus-d arc lamp of 50 volts, e f incandescent lamps of 60 and
90 volts g h electric motors of 150 and 200 volts. These combinations may
evidently be varied indefinitely care being taken to so arrange the apparatus that
the total intensities in each group, shall be as nearly as possible, equal one to the
other and equal to the intensity which the machine is capable of furnishing in
order to utilise the machine in the best possible conditions, its electro-motive force
being so regulated as to be equal to the total of those required for each group.
The exact position of the brushes upon the collector to suit the variations in the
working of the machine is constantly ensured by means of the automatic-
regulator R figures 2 and 4. This regulator is fixed on one of the machine bearings
by a bolt received in a hole S, which allows of the regulator being oscillated to
facilitate its adjustment according to the direction of motion of the machine. The
regulator is composed of two electro-magnets hi, the first of which is covered with
fine wire and is traversed by a constant current, the wire being in derivation on
the poles; the second electro-mainet i which is in tension or in circuit with the
apparatus (lamps &c) receives the total current produced by the machine and acts
differentially with the first electro-magnet h upon the soft iron rod / placed in its
core, so as to adjust to a greater or less extent the disc M which carries the
brushes.
The soft iron rods are fixed to the disc by pins which permit of its free
oscillation (see figure 4). The disc M carries with it the brushes, which thus
always occupy their exact position on the collector, according to the working of
the machine. This arrangement is intended to prevent the production of sparks
and wear of the collector and brushes and it also ensures a more regular working of
the machine. A single electro-magnet may also be employed with the regulator,
the other being replaced by a weight, spring, or its equivalent.
In machines intended for the transmission of force by means of distributing
receivers, I place upon the armature, two entirely independent circuits of wire,
either arranged in adjacent grooves of the armature-core as represented at TU
figure or superposed in the same grooves as at V. One circuit of fine wire is the
receiving circuit and receives the current from the generator placed at a distance
whereby the rotation of the armature shaft which drives the adjacent transmitting
mechanism is produced.
The second or distributing circuit of coarser wire supplies the necessary current
to the lamps, electrolytic baths or other small electro-motors placed within the
radius of the machine. The object of these arrangements is to economize expense
in the conducting wires and to employ but one machine in cases where a portion of
the force transmitted is to be converted into electricity: a greater result is in this
manner obtained.
The two circuits may be mounted on the same armature, or upon two coil-
mounted upon the same shaft; a single or separate field magnets are used for the
two circuits according to the kind of machine.
The diagram figure 9 shows the application of the distributing receiver m with
two collectors n and bi-circuit armature, combined with a generator o for working
a machine tool p, arc lamp q, incandescence lamps p and electro-motors 8.
As will be seen these machines may be used for lighting and other applications
when it is desired to supply two or more distinct circuits; for example the fine
wire circuit may be used for supplying are lamps grouped in tension and the coarse
wire circuit for supplying incandescent lamps grouped in quantity.

page_text: The several improvements hereindescribed may be applied to electric apparatus
generally but more particularly to continuous, or alternating current, machines
with separate, or consequent poles, or unipolar. They also permit of giving a
higher velocity to the armatures, or moving field magnets; afford considerable
advantages in utilizing material; enable machines to be constructed at relatively
small cost; and particularly electric motors of high tension, and small dimensions ;
they also ensure a smoother working of electric machines operated by motors
working irregularly.
Having now particularly described and ascertained the nature of the said
Invention; and in what manner the same is to be performed, I declare that what
I claim is
1st The arrangement of the field, permanent, or electro-magnets, as hereinbefore
described, and represented in the accompanying drawings.
2nd The construction and employment of hollow field, (permanent, or electro-)
magnets, as described.
3rd The construction and employment of field (permanent, or electro) magnets,
with cores of truncated, conical, or pyramidal, form, that is to say, of increasing
section, as described and represented in the drawings.
4th The construction and employment of electro magnets, having cores of any
suitable form, made in several parts, either built up segments or concentric tubes,
the wire being wound either upon one or more such parts, or upon the whole core,
as described.
5th The combination with the large field-magnets of a casing or envelope
enclosing their coils, in order to concentrate the action upon the core, as herein-
before described.
6th The use of magnetized steel bolts, or tubular magnets traversing the field
magnets for the purpose of retaining sufficient residual magnetism to rapidly charge
a self-exciting machine.
7th The construction and employment of armatures having several circuits of
wire, as described.
8th The arrangement of two collectors as represented in Figures 5 and 6 for the
purpose of diminishing the internal resistance of the armatures of machines in
which coarse wire is employed for prolonging the duration of service of the machines,
for facilitating the division of the current, and for forming machines having distinct,
and entirely separate secondary circuits, as described.
9th The construction of brush with pressure spring as shown and described.
10th The arrangement of the brushes, and conducting wires as described,
whereby the same machines may be employed to serve various kinds of apparatus
requiring different electromotive forces and intensities, such as arc, or incandescent
lamps, electric motors, ctc.
11th The application to dynamo-electric machines of a device for automatically
regulating the position of the brushes upon the collector, as herein before described,
and illustrated in the drawings.