Improvements in Dynamo-electric and Magneto-electric Machines.
Year: 1887

page_text: PROVISIONAL SPECIFICATION.
Improvements in Dynamo-electric and Magneto-electric Machines.
I, ALEXANDER MELVILLE CLARK, of the firm of A. M. and Wm. Clark, of 58,
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 Louis Maiche of 3 Rue Louis le Grand Paris France, Electrical Engineer
to be as follows:-
In dynamo-electric and magneto-electric machines, the current has heretofore been
produced by the relative motion between the permanent or electro-magnets constituting
the field or inducing portion of the machine, and the copper wiro coil constituting the
armature or induced portion of the machine. Generally, it is the armature which
revolves in the magnetic field, but sometimes it is the field magnets which revolvo
around the armature. In all cases, however, the mass in movement is very consider-
able and is proportionate to the power of the machine, and when the armature revolves,
it is necessary to employ means for collecting the currents produced.
My invention has for its object to obviate these objections, and it consists in a
machine wherein neither the inducing nor the induced coils are moved.
The principle of the invention as applied to a magneto-electric machine for example
is as follows. Both the permanent magnet forming the magnetic field and the induced
coil are fixed and the development of the induction currents in the coil is due to the
motion of an iron armature or core which traverses the said coil and is presented
alternately to the different poles of the field magnets. It is this fixity of both the
inducing and induced coils and the production of the current by the motion of an
armature or core through the induced coil that constitutes the invention, whatever may
be the arrangement and number of the several elements.

page_text: In order that the invention may be more readily understood I will describe it with
reference to the accompanying drawings forming part of this specification, in which I
have illustrated two examples of the invention Figure 1 represents a side elevation of
a two-pole machine arranged according to this invention, and figure 2 a part sectional
front elevation of same. Figure 3 is a side elevation of a machine having eight pairs.
of poles, and figure 4 a vertical section of same taken on line 1-2 figuro 3.
In figures 1 and 2, a is a permanent magnet provided with pole pieces b₁ whose
interior faces are concaved so as to closely embrace the armature coil e which is fixed
thereto and is provided with two terminals d, d from which the current is taken. The
permanent magnet a is mounted in supports e rising from a base block f. The
armature coil c is traversed by an iron shaft g mounted in bearings k upon which shaft
near the opposite ends of which are keyed at 180° to each other, sector shaped blocks
of iron so that while one, h for instance is opposite the positive pole-piece b, the
other will be opposite the negative pole piece The successive changes of polarity
of shaft and its appendages h h when rotated by means of pulley i or any other
suitable means, will have the effect of inducing currents in the coil c.
I
The permanent magnet a may be replaced by an electro-magnet excited in any
suitable manner.
In the arrangement above described the entire mass g h revolves, but the shaft g
may be fixed, the blocks h h' constituting the armature proper which present them-
selves to the poles of the field magnets, alone revolving. This arrangement may be
carried out in various ways, as for instance, the shaft g may be hollow and traversed
by a second shaft carrying the rotating blocks or armatures, or these latter may be
mounted to revolve loose upon the two ends of the stationary core. In this latter casa
the rotating armatures may either turn directly upon the stationary core or bo
separated from it by a spaco or by a sleeve of non-magnetic metal.
In order to avoid the creation of Foucault currents in the armature, it is preferred
in all cases to slit both tho central part or core and the rotating portions in any plano
passing through the axis.
Figures 3 and 4 show an example of the invention as applied to a multipolar
machine. a a' are the permanent magnets, eight in number, disposed in two series of
four each, arranged parallel to one another in frames in a similar manner to the
magnets of machines of the Alliance type.
The arinature coil c is inserted and held between the two series of magnets and is
traversed by an iron shaft d journalled in bearings e and driven by a pulley for other
means of transmission. Upon the shaft d are mounted two star wheels g g' each
having four branches, so disposed that when the four arms of wheel g are opposite the
four positive poles of magnets a, the four arms of wheel glare opposite the negative
poles of magnets a'. Under these conditions, as before, the changes of polarity of
the revolving armature constituted by the shaft d and star wheels g g' will induce
currents in coil c which, the coil being_stationary, can be readily taken without the
employment of a collector and brush. In this case also the permanent magnets may
be replaced by electro-magnets excited by any suitable means. When electro-magnets
are employed as field magnets, they may have a permanent magnet core so as to
render the machine self exciting. In this caso it is absolutely necessary that the
partial current used to excite the field should be rectified and continuous, although the
current furni-hed by the machine is alternating. For this purpose a derivation is
taken from the terminals of the machine and carried to the two extremities of the
wires of the field magnet and a voltameter is introduced into the derived circuit com-
posed of a strip of copper or other metal and a strip of aluminium immersed in
acidulated or salt water. Such a voltameter possesses the property of permitting the
passage of currents in one direction only, so that the derived current is a continuous
current utilizable for exciting the field magnets. Instead of taking the derived
current from the terminals of the machine, the armaturo coils may be wound in several
sections one or more of which would be ntilized for exciting the field magnets.
Moreover, the voltameter may be replaced by a convenient number of electric
batteries of any system having an electro-motive force equal to the electro-motive

page_text: force of the machine. In this case, the currents passing in one direction are absorbed
by the battery and regenerate the same, while the currents in the other direction
combine with the current of the battery and pass into the circuit.
The construction and arrangement of the machines on the hereindescribed principle
may be varied indefinitely, the two arrangements herein illustrated being given merely
as examples. The machines may be made of any dimensions suited to the purposes to
which they are applied, such as in electro-metallurgy electric lighting etc.
111 1
·ה
35 1 1
1 1007
A. MELVILLE CLARK.
By A. M. & Win. Clark,
53, Chancery Lane, London,
Patent Agents.

page_text: Improvements in Dynamo-electric and Magneto-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 Instituto of
Patent Agents, do hereby declare the nature of this Invention (a communication
to me from abroad by Louis Maiche, of 3 Ruo Louis le Grand, Paris, France,
Electrical Engineer), and in what manner the same is to be performed, to be par-
ticularly described and ascertained in and by the following statement :-
In dynamo-electric and magneto-electric machines, the current has heretofore been
produced by the relative motion between the permanent or electro-magnets
constituting the field or inducing portion of the machine and the copper wire coil of
the armature or induced portion of the machine. Generally, the armature revolves in
the magnetic field, but soinetimes the field magnets revolve around the armature. In
all cases, however, the mass in movement, which is proportional to the power of the
machine, is very considerable and when the armature revolves, it is necessary to
employ means for collecting the currents produced.
This Invention has for its object to obviate these objections; and it consists in a
machine wherein neither the field magnets nor the induced coil are moved. In a
magneto-electric machine, for example, both the permanent magnets which form the
magnetic field and also the induced coil, are fixed and the development of the induction
currents in the coil is due to the motion of an iron armature which passes freely
through the coil and is presented alternately to the different poles of the field magnets.
It is this fixity of both the field magnets and the induced coil, and the production
of the current by the motion of an iron armature separated from the induced coil,
that constitutes the invention, whatever may be the arrangement and number of the
several elements.
In order that the invention may be more readily understood, 1 will describe it with
reference to Figures 13 and 4 of the drawings left with the provisional Specification
and to the new figure 2 accompanying the present specification. I have illustrated two
examples of the invention. Figure 1 represents a side elevation, and Figure 2 a part
sectional front elevation, of a two-pole machine. Figure 3 is a side elevation, and
Figure 4 a vertical section (taken on line 1-2 figure 3) of a machine having eight
pairs of poles.
k
In figures 1 and 2, a is a permanent magnet provided with pole pieces 661 whose
interior faces are concaved so as to closely embrace the armature coil c which is fixed
thereto and is provided with two terminals d d from which the current is taken. The
permanent magnet a is mounted in supports e rising from a base block. The armature
coil c is traversed by an iron shaft g mounted in bearings & upon which shaft, near its
opposite ends, are keyed at 180° to each other, sector-shaped blocks of iron, so
that while the one sector h for instance, is opposite the positive pole piece b the
other will be opposite the negative pole piece . When shaft g and its append-
ages h h are rotated by means of pulley i or any other suitable means, the successive

page_text: changes of polarity thereby caused will have the effect of inducing currents in the
coil which are collected at the terminals d. The permanent magnet a may be
replaced by an electro-magnet excited in any suitable manner.
In the arrangement above described, the entire mass g h h¹ revolves, but instead of
this, the shaft may be fixed and the blocks constituting the armature proper,
which present themselves to the poles of the field magnets, alone revolve. This
arrangement may be carried out in various ways, as for instance, the shaft g may be
hollow and traversed by a second shaft carrying the rotating blocks or armatures, or
these latter may be mounted to revolve loose upon the two ends of the stationary
shaft. In this latter case, the rotating armatures may either turn directly upon the
stationary core or be separated from it by a space or by a sleeve of non-magnetic
metal.
In order to avoid the creation of Foucault currents in the armature, it is preferrod
in all cases to slit both the central part or core and the rotating portions, in any plane
passing through the axis.
Figures 3 and 4 shew an example of the invention as applied to a multipolar
machine. a a, are the permanent magnets, eight in number, disposed in two series of
four each, arranged parallel to one another in frames in a similar manner to the
magnets of machines of the Alliance type. The armature coil c is inserted and held
between the two series of magnets and is traversed by an iron shaft d journaled in
bearings e and driven by a pulley for other means of transmission. Upon the shaft d
are mounted two star-wheels gg cach having four arms so disposed that when the
four arms of wheel are opposite the four positive poles of magnets a, the four arms
of wheel are opposite the negative poles of magnets a'. Under these conditions,
as before, the changes of polarity of the revolving armature constituted by the
shaft and star wheels g g' will induce currents in coil e which, the coil being
stationary, can be readily taken off without the employment of a collector and brushes.
In this case also, the permanent magnets may be replaced by electro-magnets excited
by any suitable means.
When electro-magnets are employed as field magnets, they may have a permanent
magnet core so as to render the machine self-exciting. In this case, it is absolutely
necessary that the partial current used to excite the field magnets should be rectified
and continuous, although the current furnished by the machine is alternating. For
this purpose, a derivation is taken from the terminals of the machine and carried to
the two extremities of the wires of the field magnets and a voltameter is introduced
into the derived circuit, composed of a strip of copper or other metal and a strip of
aluminium immersed in acidulated or salt water. Such a voltameter possesses the
property of permitting the passage of currents in one direction only, so that the
derived current is a continuous current utilizable for exciting the field magnets.
Instead of taking the derived current from the terminals of the machine, the
armature coils may be wound in several sections, one or more of which would be
utilized for exciting the field magnets. The voltameter may also be replaced by a
series of voltaic cells having an electro-motive force equal to that of the machine. In
this case, the currents in one direction are absorbed by, and regenerate, the battery,
while the currents in the other direction combine with the current of the battery and
pass into the circuit.
The construction and arrangement of the machines on the herein described principle
may be varied indefinitely the two arrangements herein illustrated being given
merely as examples. The machines may be made of any dimensions suited to the
purposes to which they are applied, such as in electro-metallurgy, electric lighting, etc.
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 ;-
1. A dynamo-electric or magneto-electric machine in which both the field magnets
and armature coil are stationary and the current is generated by the motion of an

page_text: iron core or armature of any suitable form, traversing the armature coil and moving
in the magnetic field, as herein before described.
2. The herein-described method of exciting the field electro-magnets of an alternating
current machine, which consists in rectifying a portion of the current by means of a
voltameter of tho kind herein-described, or by means of a series of voltaic cells having
an electro-motivo force equal to that of the machine, the currents in the one direction
being absorbed by, and regenerating, the battery, while the currents in the other
direction combine with the current of the battery as specified.
Dated thi 32-11
T
1000
A. MELVILLE CLARK.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.