IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES
Year: 1882

page_text: LETTERS PATENT to John Henry Johnson of 47 Lincoln's Inn Fields in the
County of Middlesex Gentleman for an invention of "IMPROVEMENTS IN
DYNAMO-ELECTRIC MACHINES."-A communication from abroad by Jean
Marie Anatole Gerard-Lescuyer of Paris in the Republic of France Engineer.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 19th April 1882.
"
JOHN. HENRY JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN DYNAMO ELECTRIC MACHINES A communi-
cation from abroad by Jean Marie Anatole Gerard Lescuyer of Paris in the
Republic of France, Engineer.
This Invention relates to improvements in dynamo-electric machines and it
consists in a novel and special arrangement of the parts as hereinafter described..
The invention is based on a peculiar mode of coiling the wire upon the revolving
armature or induced part of the machine together with a special construction and
arrangement of this induced part for the purpose of still further augmenting the
electro magnetic action which is considerably increased by the said peculiar mode
of winding the wire upon the armature, and another distinguishing feature of the
invention consists in the novel arrangement of the commutator.
When one pole of a magnet is brought near one extremity of a bar of soft iron,
upon which an insulated wire is wound an induced current is set up in the wire
and when the opposite pole of another magnet is also brought near the opposite
extremity of the same bar the intensity of this current will be doubled but on the
other hand if two poles of the same denomination were brought near the ends of
the same bar two currents the one inverse to the other would be produced which
currents would neutralise one another.
However if the direction in which the wire is wound is changed or reversed at
about the middle of the bar two currents of the same denomination will be

page_text: generated which will combine together. The two similar poles act on the
extremities of the bar and produce thereon two poles of the opposite denomination
and a consequent pole is thereby produced at the middle of the bar of the same
denomination as the inducing poles.
Under these conditions when two supplementary poles of the opposite denomi-
nation are now brought near to this consequent pole the magnetism of the whole
system will be strengthened and an induced current of much greater intensity will
be produced.
In this case the bar inay assume the form of a cross upon the vertical arms of
which the wire is coiled in opposite directions and be arranged between. two
inductor poles of one denomination and two supplementary poles of the opposite
denomination.
When a bar thus arranged is caused to rotate inductor poles remaining stationary
an induced current will be produced in the wire at each quarter of a revolution.
The wire being carried bodily through the magnetic fields is acted upon in a direct
manner whereby the effect of the induction is still farther augmented.
In place of employing four stationary poles twelve, twenty four, or other suitable
number may be employed in order to diminish the speed and under these conditions
an induced current will be set up in the wire at every twelfth, twenty-fourth, or
other corresponding finction of a revolution.
It is evident that the same arrangement of crossed poles of opposite denomi-
nations would produce the same maximum amount of effect it the method of
winding the wire according to this invention with a consequent pole is carried out
on a disc in place of the cross herein before described. This method of establishing
induced currents is based upon the same principle of changing the direction for
winding the wire as in the case of the crossed poles of opposite denominations in
order to augment the intensity of the consequent point resulting from the said
change of direction.
It has been herein stated that the maximum of inductive effect is obtained by
the crossed poles and in fact it is not possible to obtain a more powerful action in
proportion to the power of the inductor even by multiplying the number of con-
sequent points in the winding. The fact may be easily explained by making
allowance for the weak inverse current induced by the influence of the poles on the
returning length of wire connecting each coil.
The action of the improved machine will be readily comprehended by means of
the foregoing brief explanation of the theory of the leading principles of the
invention.
In currying out this Invention the magnetic field of the improved dynamo
electric machine is produced by say four electro-magnets secured to the end frames
or standards of the machine the said standards being connected together by means
of bars or stays. This particular number and arrangement of the inducing electro-
magnets is not essential and may be modified according to the purposes to which
the machine is to be applied. The induced part or armature which is arranged to
rotate at a high speed within the magnetic field is provided with coils of wire
arranged in accordance with the principles herein before described being also provided
on each side with four bosses or projections acting as poles.
The induced wire may be divided into two equal or unequal parts one part being
connected with the inductors and serving to produce the magnetic field while the
other forms the external circuit; by not changing the direction of the currents of
this second part alternate currents will be obtained. The inductor may also be
arranged in derivation. upon the induced current.
Outside the framing at the ond opposite to that at which the driving drum is
situated is arranged a commutator hereinafter described and which forms one of
the features of this invention. This commutator is constructed with a cylinder
made in two parts portions of which are cut away in such a manner as to leave
two segments of cylinders on each part of a length and breadth about equal to the

page_text: space between them so that the two parts being insulated from each other brought
together in such a manner that the projecting parts of the one fill the recesses of
the other the one part being insulated from the other part so that the said parts
thus together constitute the complete cylinder or sleeves of the commutator.
This cylinder or sleeve turns in contact with two springs rubbers or brushes held
at right angles with respect to one another in cylindrical holders provided at each
end of a sector carried on the shaft of the machine. In order to adjust the position
of the springs this segment is caused to turn upon the shaft being guided or
steadied by a stud and screw working in a slot at its upper part.
Although it is preferred to arrange the commutator as described outside the
framing this arrangement is not essential as the said commutator may be placed at
any other suitable point on the shaft of the machine.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Henry Johnson in the Great Scal Patent Office on the
18th October 1882.
JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES." A communication
from abroad by Jean Marie Anatole Gérard-Lescuyer of Paris in the Republic of
France, Engineer.
This Invention relates to improvements in Dynamo-electric machines and it
consists in a novel and special arrangement of the parts as hereinafter described.
The Invention is based on a peculiar mode of coiling the wire upon the revolving
armature or induced part of the machine together with a special construction and
arrangement of this induced part for the purpose of still further augmenting the
Electro magnetic action which is considerably increased by the said peculiar mode
of winding the wire upon the armature and another distinguishing fenture of the
Invention consists in the novel arrangement of the commutator.
In order that the Invention may be clearly understood I have illustrated on the
annexed sheet of drawings both the theoretical principles which have led up to the
gradual perfection of the Invention and the machine itself simply as an example of
the mode of carrying out the Invention in practico.
Figure 1 is designed to illustrate the Law discovered by Faraday. When one
pole of a magnet is brought near one extremity of a bar of soft iron upon which an
insulated wire is wound an induced current is set up in the wire and when the
opposite pole of another inagnet is also brought near the opposite extremity of the
same bar the intensity of this current will be doubled but on the other hand if two
poles of the same denomination were brought near the ends of the same bar twọ
currents the one the reverse of the other would be produced which currents would
neutralize one another.
If however the direction in which the wire is wound be changed or reversed at
about the middle of the bar two currents of the same denomination will be
generated which will combine together. Figure 2 illustrates this arrangement of
the wire. The two similar poles N N act on the extremities of the bar upon which
the wire is coiled and produce thereon two poles S., S., of the opposite denomination
and a consequent pole is thereby produced at the middle a of the said bar of the
same denomination as the inducing poles N N.
Under these conditions when two supplementary or reinforcing poles of the
opposite denomination are now brought near to this consequent pole at the middle a
of the said bar the magnetism of the whole system will be strengthened and an
induced current of much greater intensity will be produced than is attained by the
arrangement illustrated by Figure 1.
This arrangement is illustrated in figure 3. The part around which the wire is
coiled may in this case assume the form of a cross upon the vertical arins of which
the wire is coiled in opposite directions and be arranged between two inducing
poles of one denomination and between two supplementary or reinforcing poles of
the opposite denomination. indicates the point at which the change of direction
takes place. N N the inductor - poles and S S the supplementary or reinforcing
poles.
When a bar, thus arranged is caused to rotate, the inducing poles romaining
stationary, an induced current will be produced in the wire at each quarter of a
revolution. The wire being carried bodily through the magnetic fields is acted
upon in a direct manner whereby the effect of the induction is still farther
augmented.

page_text: In place of employing four stationary poles, twelve, twenty four or other
suitable number of such poles may be employed in order to diminish the speed and
under these conditions an induced current will be set up in the wire at every
twelfth or twenty fourth or other corresponding portion of a revolution.
It is evident that the same arrangement of crossed poles of opposite denomi-
nations would produce the same maximum effect if the method of winding the wire
according to this Invention with a consequent pole is carried out on a disc as
represented in figure 4 in place of the cross as herein before described.
An inspection of the drawing will show at once that this method of establishing
induced currents illustrated in detail in figures 7 and 8 (which are respectively a
plan and elevation of an armature) is based upon the same principle of changing the
direction for winding the wire herein before described in connection with crossed
poles of opposite denominations in order to augment the intensity of the consequent
pole resulting from the said change of direction.
It has been herein before stated that the maximum of inductive effect is obtained
by the arrangement illustrated in Figure 3 and in fact it is not possible to obtain
a more powerful action in proportion to the power of the inductor even by multi-
plying the number of consequent poles in the winding. This fact may be easily
explained by making allowance for the weak inverse current induced by the
influence of the poles on the returning length of wire connecting each coil. The
intensity of this reversed current which has to be deducted from that of the direct
induced current is equivalent to about thirty per cent of the latter so that the
available induced current is equal to about seventy per cent, of the total energy.
The action of the improved machine illustrated in side and end elevation in
Figures 5 and 6 respectively and in perspective in Figure 9 will be readily compre-
hended by means of the foregoing brief explanation of the theory of the leading
principles of the Invention.
The said Figure 6 is a view of the commutator end of the machine and the
general arrangement of the apparatus is clearly shown by the perspective view in
Figure 9.
An improved machine constructed or arranged according to this Invention is
illustrated by an example wherein the magnetic field is produced by four electro
magnets on each side of the armature the said magnets being secured to the end
frames or standards c of the machine which standards are connected together by
means of bars or stays d.
It is to be understood however that this particular number and arrangement of
the inducing electro magnets is not essential and may be modified according to the
purposes to which the machine is to be applied.
The induced part or armature e of the machine is arranged to be rotated at a
high speed within the magnetic field and is provided with coils of wire arranged
in accordance with the principles hereinbefore described being also provided on
each side with four bosses or projections from each side acting as poles. The
induced wire may be divided into two equal or unequal parts one part being
connected with the inductors. and serving to produce the magnetic field whilst the
other forms the external circuit, By not changing the direction of the currents of
this second part alternate currents will be obtained.
The inductors may also be arranged in derivation upon the induced current.
Outside the framing c at the end opposite to that at which the driving drum is
situated is arranged a commutator which forms one of the features of this
Invention. This commutator is constructed with a cylinder h made in two parts
portions of the sides of each of which are cut away in such a manner as to leave
two segments or portions of cylinders on each part of a length and breadth about
equal to the space between them so that the two parts being brought together in
such a manner that the projecting parts of the one fill the recesses of the other
insulating material intervening between the parts, the said parts thus together
constitute the complete cylinder or sleeve of the commutator.
This cylinder or sleeve turns in contact with two springs rubbers or brushes i

page_text: held at right angles with respect to one another in cylindrical holders & carried at
cach end of a sector & carried on the shaft of the machine. In order to adjust the
position of the said rubbers ȧ this sector is caused to turn upon the shaft of the
machine being guided or steadied by a stud working in a slot m and being fixed in
position by the screw m³.
Although it is preferred to arrange the commutator outside the framing as
described and illustrated this arrangement is not essential as the said commutator
may be placed at any other suitable part of the shaft of the machine.
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried into
offect I would observe in conclusion that what I consider to be novel and
original and therefore claim as the Invention secured to me by the hereinbefore in
part recited Letters Patent is :-
First-The arrangement or combination of parts constituting the dynamo
electric machine hereinbefore described and illustrated in the accompanying
drawings.
Second In dynamo electric machines the employment of induced parts or
armatures having the wire or wires thereof wound in reverse directions and used
with inducing poles substantially as and for the purpose hereinfore described with
reference to the accompanying drawings.
Third-The employment in dynamo electric machines of a commutator and its
springs rubbers or brushes arranged constructed or combined substantially as
herein before described and illustrated in the accompanying drawings.
In witness whereof I the said John Henry Johnson have to this my
Specification set my hand and seal this eighteenth day of October One
thousand eight hundred and eighty two.