IMPROVEMENTS IN DYNAMO- ELECTRIC MACHINES
Year: 1881

page_text: LETTERS PATENT to James Edward Henry Gordon of Kensington in the
County of Middlesex for an Invention of "IMPROVEMENTS IN DYNAMO-
ELECTRIC MACHINES."
PROVISIONAL SPECIFICATION left by the said James Edward Henry
Gordon at the Office of the Commissioners of Patents on the 17th December
1881.
JAMES EDWARD HENRY GORDON of Kensington in the County of Middlesex
"IMPROVEMENTS IN DYNAMO ELECTRIC MACHINES"
My Invention relates to improvements in dynamo machines and particularly in
that described by me in Specification No. 78 1881.
In the machine described in that Specification the revolving rings each carry the
same number of magnet coils as the fixed rings carry armature coils the Drawings
annexed to the Specification shew them as each carrying 16 coils. The armature
coils were also made cylindrical and of the same diameter as the magnets each
being placed close to the next. I have found that these coils act on each other
by mutual induction in a very injurious manner during the working of the
machine.
If a certain number of lamps are being maintained by one coil closing the circuit
of the next to it on one side reduces the light of the lamps on the first by some 20
or 30 per cent-Closing the circuit of the next of the other side still further reduces
it by a like amount. The reason is that as the currents in contiguous coils
circulate in opposite directions they are in the same direction in those parts of the
two coils which are immediately contiguous to each other. As the currents in the
two coils are both increasing at the same time they retard each other by their
mutual action.
In the arrangement of the machine which is the subject of the present Patent
this drawback is got rid of by making the number of armature coils twice the
number of the magnet coils. The magnets therefore act alternately on the
alternate set of coils. For instance at the instant when the 16 magnets are opposite
to the alternate coils 1. 3. 5. up to 31 the other alternate coils 2. 4. 6. up to 32 are
removed from their influence and therefore are practically idle 1 and 5 still tend
to act injuriously on 3 as before but being separated from it by the thickness of
coils 2 and 4 their action is so small as to be unnoticeable 1 and 3 induce electro
motive forces in the two sides of 2 respectively but these are equal and in opposite
directions and so produce no current or change of current in 2.

page_text: "
In coupling several coils together either in quantity or series, those coils only
which belong to the same set of alternate coils should be coupled. For instance if
it were desired to connect coil 1 with two other coils 3 and 5 would be used and
not 2 and 4.
As in the case of the arrangement given in the Patent above referred to each of
the coils can be used for a separate circuit or they can be connected in groups to
form a smaller number of more powerful circuits. The several groups also need
not all be composed of the same number of coils some groups may have more coils
in them than others.-Or the whole machine can if desired be connected so as to
form two circuits, one obtained from all the coils, 1. 3. 5 &c. the other from all
coils 2. 4. 6. &c.
In order to economise space and get more wire on the machine the fixed coils
may be made wedge shaped the sides of the wedge being planes radial to the axis
of the fixed ring that carries them.
The cores are preferably solid soft iron and consist of flat wedges whose sides are
parallel to the outer surfaces of the coils. The cores have flanges fixed to their
ends each end of the core is for this purpose cut away around its circumference to
form a shoulder. The reduced end is passed through a corresponding hole in the
plate which is to form the flange and is rivetted over or otherwise held to the
plate.
I prefer to lengthen greatly the end flanges of the coils in the fixed rings of the
machine other than the two outside fixed rings in the direction leading away from
the centre of the machine. Instead of having cups in these fixed rings in which
the coils are partially embedded I use a plain ring_whose two sides.are-planed flat-
and whose width is equal to the inside width between the flanges of the coils.
The prolongation of the flanges of the coils are firmly secured by bolts to the ring
or to flanges at its sides. By thus making the flanges of the coils long and the
ring large the ring may be sufficiently removed from the action of the magnets to
allow of its being made of iron instead of brass. The flanges are perforated with
as many slits as possible compatable with the required strength to check the
circulation of currents. I find it preferable to make the flanges of the coils of
German silver which is very rigid and opposes a high resistance to the circulation
of currents in it. The half coils on the outer rings are of the same wedge shape as
the cores and coils in the central ring or rings, but the flange next to the magnets
is of brass or preferably German silver and is not prolonged. The coils are sup-
ported by their cores being carried through a stout iron plate which is fixed in the
same manner as the central rings.
In order that power may not be wasted in inducing currents in this plate it is
set back some distance the cores being correspondingly prolonged. The space
between the wire of the coils and the iron plate may be filled up by wooden plates
which form the second flange of each coil and may be an inch or
thickness.
more in
I find for most carbon lamps both arc and incandescent that with my present
sized machine wires of diameters from 112 to 134 inch are useful and suitable to
the armature coils.
The improvement herein before described in the flanges of the coils of the
dynamo machines consisting in making them of German silver is applicable not
only to machines constructed as above described but also to other dynamo
machines.
The improvement also of employing twice as many coils as there are magnets
is applicable to the well known Siemens dynamo machine commonly used for
producing alternate currents. This machine is shewn at Figures 1 and 2 Sheet 3
of the Drawings annexed to the Specification of a Patent No. 3134 in the year
1878 in which the coils revolve and the magnets are fixed.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said James Edward Henry Gordon in the Great Seal Patent Office
on the 17th June 1882.
JAMES EDWARD HENRY GORDON of Kensington in the County of Middlesex
"IMPROVEMENTS IN DYNAMO ELECTRIC MACHINES'
"3
My Invention relates to improvements in dynamo machines and particularly in
that described by me in Specification No. 78, 1881.
In the machine described in that Specification the revolving rings each carry
the same number of magnet coils as the fixed rings carry armature coils the
Drawings annexed to the Specification shew them as each carrying 10 coils. The
armature coils were also made cylindrical and of the same diameter as the magnets
each being placed close to the next. I have found that these coils act on each
other by mutual induction in a very injurious manner during the working of the
machine.
If a certain number of lamps are being maintained by one coil, closing the
circuit of the next to it on one side reduces the light of the lamps on the first by
some 20 or 30 per cent. Closing the circuit of the next on the other side still
further reduces it by a liko amount. The reason is that as the currents in
contiguous coils circulate in opposite directions they are in the same direction in
those parts of the two coils which are immediately contiguous to each other. As
the currents in the two coils are both increasing at the same time they retard
each other by their mutual action.
In the arrangement of the machine which is the subject of the present Patent
this draw back is got rid of by making the number of armature coils twice the
number of the magnet coils. The magnets therefore act alternately on the alternate
sets of coils. For instance at the instant when the 16 magnets are having their
maximum action on the alternate coils 1. 3. 5 up to 31 the other alternate coils. 2. 4. G
up to 32 are practically idle. 1 and 5 still tend to act injuriously on 3 as before
but being separated from it by the thickness of coils 2 and 4 their action is so
small as to be unnoticeable. 1 and 3 induce electro motive forces in the two sides
of 2 respectively but these are equal and in opposite directions and so produce no
current or change of current in 2.
In coupling several coils together either in quantity or series those coils only
which belong to the same set of alternate coils should be coupled. For instance if
it were desired to connect coil 1. with two other coils 3 and 5 would be used and
not 2 and 4.
As in the case of the arrangement given in the Patent above referred to each of
the coils can be used for a separate circuit or they can be connected in groups to
form a smaller number of more powerful circuits. The several groups also need
not all be composed of the same number of coils some groups may have more coils
in them than others. Or the whole machine can if desired be connected so as to
form two circuits, one obtained from all the coils 1. 3. 5 &c. the other from all
coils 2. 4. 6 &c.
In order to economise space and get more wire on the machine the fixed coils
may be made wedge shaped the sides of the wedge being planes radial to the axis
of the fixed ring that carries them.
The improvement of employing twice as many coils in each armature ring as
there are magnets in each magnet ring is applicable not only to dynamo machines
constructed as described in the Specification of the Patent granted to me No. 78 in
the year 1881--but also to all dynamo machines in which the cores of the electro
magnets and of the helices are straight and parallel with the axis of the machine

page_text: whether the circle of the magnets-be carried by the revolving axis whilst the
circle of helices are fixed or whether the circle of helices are carried by the axis
whilst the circle of magnets are fixed as in the well known Siemens dynamo-
machine commonly used for producing alternate currents.
The cores are of soft iron and may be either solid soft wrought iron or when
the machine is large may consist of two or more plates of the same or the core may
be constructed in the manner described in a Provisional Specification lodged by me
on this 17th day of June 1882 and as is shewn in the Drawings hereunto
annexed.
I find it preferable to make those flanges of the fixed coils which are near the
magnet poles of German silver which is very rigid and opposes a high resistance to
the circulation of clectric currents in it.
The improvement in the flanges of the coils consisting in making them of
German silver or such like metal or alloy instead of brass or other metal of higher
conductivity is applicable not only to my dynamo machine No. 78 1881, but to
all other dynamo machines where the armature coils have flanges so placed that
the magnets tend to induce currents in them.
To still further diminish the circulation of the currents the flanges are perforated
with as many slits as possible without unduly weakening the plate such slits being
approximately at right angles to the directions in which the currents would
circulate.
The connection of the outer ends of the cores of the coils on the outer rings I
make by prolonging the cores outwards away from the magnet coil and securing
them into a fixed iron ring-shaped-plate-which-forms-their support.
-In order that power may not be wasted in. inducing currents in this plate it is
set back some distance the cores being correspondingly prolonged. The space
between the wire of the coils and the iron plate may be filled up with wooden
plates or blocks which form the second flange of the coil these wooden plates or
blocks may be from 1 inch to 3 or more inches in thickness.
This improvement may be applied to any machine where the inducing magnets
act on one end of the iron cores of the armatures whilst the other ends are secured
to an iron plate or plates.
In order that my Invention may be better understood I will proceed to describe
the Drawings annexed which represent a machine containing the improvements
described above and also containing other improvements described in my
Provisional Specification of June 17th 1882
Figure 1 shews a side elevation Figure 2 an end elevation and Figure 3 a plan
of the machine, one half of each of the above Figures is shown in section.
Figure 4 shews a section of one of the fixed rings and one of the helices carried by
it. Figure 5 an elevation of part of one of the fixed rings the way in which each
helix is built up and secured to the ring is illustrated in this Figure. Figures 6,
7 and 8 shew full sized views of one of the fixed coils and Figures 9 and 10 full
sized views of one of the magnets.
The machine represented in the Drawings is in many respects similar in principle
to the machine described in Patent No. 78 1881 but is of very large size and is
intended to be driven direct from the steam engine without belt or other
multiplying gear. It contains only one wheel of magnets and therefore only the
two fixed rings of so called half coils" and not the ring shewn in the Drawings
annexed to the Specification of my Patent No. 78 in the year 1881 placed between
the two wheels of magnets.
"
In the machine shewn in the Drawings hereunto annexed the revolving wheel is
8 feet diameter at the magnet centres. The sole plate is 13 feet 4 inches long
by 7 feet wide, these dimensions however are only the dimensions of a particular
machine and are not the only useful dimensions as the machine may be made
either smaller or larger as desired.
The wheel is built up of wrought iron boiler plates though steel plates might
be used.

page_text: The wheel consists of two central discs A and of two cones B whose bases fit
upon the central discs and through whose apices the main shaft C passes.
The discs A and cones B are made of segmental pieces of boiler plate so cut
that the grain of the plate is radial to the wheel at the centre of each segment.
The segments are rivetted together with butt strips in the way usual in boiler
making.
The discs A are kept apart at the centre by a cast iron distance piece D. At
the rim they are kept apart by a wrought iron ring E. The cones B are of less
diameter than the discs so as to leave a space of flat disc all round exterior to the
cones. The cones and disc are separated at the centre by massive cast iron bosses F,
turned square to the shaft where they butt against the disc and conical where they
butt against the cones. The cast iron distance piece D is of somewhat larger
diameter than the bosses so that the discs can be rivetted to it without the heads
of the rivets interfering with the bosses. The cones discs ring distance piece and
bosses are all firmly rivetted and bolted together being still further strengthened
by angle pieces placed between the disc and the cones.
The
The discs are rivetted with double butt strips the cones with single ones.
butt strips of the cones are placed inside them and the rivet heads countersunk so
that the outsides of the cones have perfectly smooth surfaces.
The flat outer portion of the wheel receives the magnets G which in the machine
from which these Drawings are taken are 32 in number.
Each magnet consists of a cylindrical iron core G' of two bobbins G³, of brass or
other metal other than iron containing wire, and of two pole pieces G³. The core G¹
passes right through a hole in the discs A and wrought iron ring E and is fixed 80
as to project equally on both sides. The brass bobbins are then slipped on one at
each side of the disc and the pole plates being fixed on hold the bobbins in their
places. The pole plates are of iron preferably wrought, their sides are not parallel
but form radii of the magnet wheel.
One method of securing the cores and pole plates is shewn in the Drawings but
other methods may be used.
The shaft C runs in bearings preferably of phosphor bronze which are carried by
the side frames H.
There is a large gap or opening I' in the sole plate I through which a portion of
the wheel dips into a pit below the machine. This enables the centre of gravity to
be kept low and greatly increases the stability of the machine.
The end thrust is taken by two loose iron collars K placed on the shaft and
pressed gently against the inside ends of the phosphore bronze journals by means of
set screws projecting from the ends of the cast iron bosses. These set screws are
secured by lock nuts.
The collars K also carry the contact rings L for conveying the exciting current
to the magnets. The rings are preferably of phosphor bronze and are separated
from the iron collars by split rings of vulcanite or other insulator. Brushes not
shewn in the Drawings press on them in the ordinary way, to convey the exciting
current to them. M are fixed rings of cast iron carrying the fixed coils. They are
supported by being bolted to the inside of the gap in the sole plate at M M and
by the four cast iron struts M², They are also tied together by the seven screwed
rods M³.
Each fixed ring is made in three segments one being much smaller than either of
the other two. This is for the reason that if one of the magnet coils breaks down
it can readily be got at by removing the small segment of one of the fixed rings
and turning the wheel until the damaged coil comes opposite to the gap so produced
in the ring the damaged coil can thus quickly be removed and replaced by another
one as described in the Provisional Specification above mentioned.
64 fixed coils or so called "half coils" are fixed to each ring so that the 64 poles
facing the magnet wheel are acted on by the 32 magnet poles facing them, the
number of coils thus being twice the number of magnets as herein-before stated.
The details of the fixed coils are shewn on a larger scale in Figures 6. 7. and 8.

page_text: The wedge shaped core N consists of a sheet of boiler plate bent upon itself so
that the angle forms the thin end of the wedge and the free edges which do not
quite meet form the thick end.
The wedge shaped head of a T piece O is inserted into one end of the folded
plate and welded to it and the stem of the T being turned and screwed is passed
through a hole in the fixed ring and is secured by lock nuts O¹
The wooden block P, herein before mentioned is slipped onto the core and secured
by one or more pins.
The German silver flange Q is rivetted onto a shoulder cut on the end of the
core. In addition to the slots which are cast in it a cut Q is made passing
completely through into the opening of the core. Projecting lugs Q2, are cast on
the German silver which clip into the opening in the core and prevent the slot Q₁
from opening. The flange may be further secured by being made to project beyond
the wire in places Q³ and being secured to the wood by long screws and distance
pieces. These screws must of course be inserted after the wire is wound.
R. R represent the holding down bolts.
The shaft is coupled direct to a steam engine or to two steam engines one at
each end.
In the machine from which the Drawings are taken the wire both on magnets
and on armature coils is 185 inch in diameter.
The magnets may be excited by a direct current produced in any ordinary way.
Having now described my Invention I would have it understood that what I
claim is :-
-First-In-dynamo machines in which the cores of the electro magnets and of the
helices are straight and parallel with the revolving axis of the machine making
the number of helices in each ring double the number of the electro magnets in
each magnet ring whether the helices are fixed and the magnets carried by the
revolving axis or vice versa.
Second. I claim the improvement in dynamo machines applicable to all machines
where one end of each armature core is acted on by the magnets and the other ends
of the cores are connected by an iron plate consisting in lengthening the cores
beyond the length required for the wire and thus setting back the iron plate into
a field of greatly diminished inductive action. The space between the wire and
the plate may be either left empty or filled with wood or by other non-conductor.
In witness whereof I the said James Edward Henry Gordon have hereunto
set my hand and seal this Seventeenth day of June in the year of our Lord
One thousand eight hundred and eighty two.