IMPROVEMENTS IN DYNAMO ELECTRIC MACHINES
Year: 1882

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
19
PROVISIONAL SPECIFICATION left by the said James Edward Henry
Gordon at the Office of the Commissioners of Patents on the 17th June
1882.
JAMES Edward HENRY GORDON of Kensington in the County of Middlesex.-
"IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES "
My Invention relates to improvements in the machine described in the
Specification of a Patent granted to me No 78 in the year 1881 improvements
upon which were also described in the Provisional Specification lodged by me
No 5586 in the year 1881 and in machines of analogous nature and construction.
The present invention relates to improvements in the mechanical construction of
the machine and also to a commutator intended to take up the alternate currents
in such a machine and convert them into direct currents useful for charging
secondary batteries and for other purposes.
.
The revolving wheel I make of two discs of wrought iron or steel mounted upon.
the revolving axis and kept at a short distance apart from one another at the axis
by a cast iron distance piece placed between them. At the rim they are kept
apart by a wrought iron or steel ring interposed between them-this ring carries
the electro magnets.
On to the shaft are also keyed two cast iron bosses with conical ends one on
either side of the two disca the bases of the cones being inwards towards the
discs. To each such conical end is secured the apex of a wrought iron or steel
cone the base of each of these cones is secured to one of the two wrought iron
discs at a distance of a few inches from its circumference these few inches of the
outer extremity of the wheel are thus left flat for the magnets to be secured to it.
The cast iron distance piece 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
Price 6d1

page_text: =
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.
Each magnet consists of a cylindrical iron core of two bobbins of brass or
other metal containing wire and of two pole pieces. The core passes through
a hole in the flat portion of the disc near its outer circumference and is fixed
so as to project equally on both sides. The brass bobbins are then slipped on
one at each side of the disc and when the pole plates are fixed on the extremities
of the cores they hold the bobbins in their places. The pole plates are of iron
preferably wrought. Two of the planes bounding them are radial to the magnet
wheel and they are made a little shorter than the fixed coils and about two thirds
the width of a fixed coil.
The shaft runs in bearings preferably of phosphor-bronze which are carried on
low standards on the top of the sole plate.
A large gap or opening is made in the sole plate 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 placed on the shaft and pressed
gently against the inside ends of the phosphor-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 also carry the contact
rings 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 press on them in the ordinary way and
convey a current to them.
The fixed coils are carried by rings of cast iron. The fixed rings are supported
by being bolted to the inside of the gap in the sole plate and by four cast iron
struts from the top of the low standard on the sole plate. They are also tied
together by tie rods.
Each fixed ring is made in three segments one being much smaller than either
of the other two.
The reason for this is that if a fixed coil should break down the power of the
machine is only diminished by the loss of that coil and therefore the broken coil
can be left till there is a convenient opportunity to take the machine to pieces but
if a revolving coil breaks down it must be repaired at once before the machine can
be worked by removing the small segmental piece from one of the fixed rings and
turning the wheel till the damaged coil comes to the opening thus made it is
rendered accessible without the necessity of taking the machine to pieces.
The cores of the fixed coils are wedge shaped and consist each 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.
AT piece with a wedge shaped head is inserted into one end of the folded plate
and welded to it the stom of the T piece is screwed and passed through a hole in
the fixed ring and is secured by lock nuts.
A wooden block is slipped on to the core and secured by one or more pins.
This block forms the back flange.
A German silver flange is rivetted on to a shoulder cut on the end of the core
near the revolving wheel. In addition to the slits which are cast in this flange a
cut is made passing completely through into the opening of the core.
Projecting lugs are cast on the German silver flange which dip into the opening
in the core and prevent the slit in the core from opening-The flange may be
further secured by being made to project beyond the rim at its outer extremities
and being secured to the wood by long screws and distanco pieces. These screws
must of course be inserted after the wire is wound.
The exciter may be any suitable machine giving a direct current or the current
from some or one of the coils of the machine may by aid of the commutator be
used to excite the magnets.

page_text: The commutator which has been added to the machine is intended to convert the
alternate currents into a 'direct one.
The novelty in it in which it difers from former commutators is the arrangement
by which one commutator picks up the two sets of alternate currents differing in
phase namely the currents of coils, 1. 3. 5. 7 &c. and those of the coils 2. 4. 6. 8, &c.
and converts both sets into one direct current..
The commutator consists of a barrel. of wood or other non conductor surrounded
at each end with a metallic ring. From the inner edge of each metallic ring strips
of metal extend parallel with the axis. There are half as many strips projecting
from each ring as there are magnets in the magnet ring.
The strips projecting from one ring are opposite to the strips projecting from the
other ring but they do not meet.
The barrel at its centre is surrounded by a metallic ring from the opposite sides
of which project a corresponding number of tongues these tongues lie in the spaces
between the tongues of the two end rings but are not in contact with them. Two
metallic brushes rest upon the metallic tongues on one side of the central ring
and two metallic brushes upon the metallic tongues on the other side of the central
ring.
The two brushes of one pair are connected one to one end of the coils 1. 3. 5. 7
&c. and the other to the other end of those coils. The two brushes of the other
pair are similarly connected to the coils 2. 4. 6. 8 &c. When the end of one brush
of either pair is over the central line of one of the tongues projecting from the end
ring the end of the other brush is over the central line of a tongue projecting from
the central ring, At the same time the ends of the other brushes (which are at
the same relative distance in advance one of the other) will be just leaving the
edges of tongues that they had previously passed over and passing over insulating
spaces on to other tongues. The direct currents produced are taken off by brushes
which press on the two end rings which surround the barrel.
The brushes are of any convenient construction but I prefer a solid brass plate
pressed down by a spiral spring from its pivot and carrying on its underside a
number of strips of thin sheet copper.
The frame carrying the four brushes can be moved alightly round the axis for
adjustment.
An extra brush may if required be made to press on the middle ring so as to
allow either half of the machine to be used independently.
When it is desired to make the machine self exciting it may be furnished with
two commutators one of which is connected to a few coils for commutating the
exciting current and the other to the rest of the coils for commutating the main
current for external use.
It is of course possible to connect part only of the coils to the commutator so as
to obtain direct and alternate currents simultaneously from different portions of
the machine,
Another way to arrange this commutator is to make the barrel with the same
number of strips on it as there are magnets in the magnet wheel the strips running
nearly from end to end of the barrel. At each end of the barrel is a metal
ring. Half the strips i.e. the 1st 3rd 5th &c. are connected to one ring and half ¿.e.
the 2nd 4th 6th & to the other.
The brushes are arranged in the same manner and with the same differences of
lead as in the former case the four brushes carried on the adjusting frame and
which are connected to the machine coils resting on the strips and the two brushes
connected to the line resting on the end rings. The extra central brush would not
be used.
The arrangement first described connects the two sets of coils in series the latter
one connects them in quantity.
In order to save the expense of lengthening the massive main shaft of the machine
the commutator is mounted with a thin shaft on an independent stand and its
shaft is coupled to that of the machine.

page_text: In order to prevent sparking the commutator may run in a trough filled with a
non-conducting liquid.
Another way to prevent sparking is to keep a blast of cold air continually
blowing on the barrel at the points of contact with the brushes.
It is understood that this machine may be used either with or without its
commutator as the commutator can be disconnected by simply uncoupling the two
shafts.
For instance the machine might be used in the day time with its coils coupled
for bigh E.M.F. and with the commutator to charge secondary batteries at a distance
and at night it might be used without the commutator and with the coils in quantity 1
to produce alternate currents of low E.M.F, for lamps near it.
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 16th December 1882.
JAMES EDWARD HENRY GORDON of Kensington in the County of Middlesex 1
"IMPROVEMENTS IN DYNAMO ELECTRIC MACHINES "
My Invention relates to improvements in the machine described in the Specifi-
cation of a Patent granted to me No. 78 in the year 1881 improvements upon
which were also described in the Provisional Specification lodged by me No. 5536
in the year 1881 and in machines of analogous nature and construction.
The present invention relates to improvements in the mechanical construction of
the machine.
The revolving wheel I make of two discs of wrought iron or steel mounted upon
the revolving axis and kept at a short distance apart from one another at the axis
by a cast iron distance piece placed between them. At the rim they are kept
apart by a wrought iron or steel ring interposed between them-this ring carries
the electro magnets.
On to the shaft are also keyed two cast iron bosses with conical ends one on
either side of the two discs, the bases of the cones being inwards towards the
discs. To each such conical end is secured the apex of a wrought iron or steel
cone the base of each of these cones is secured to one of the two wrought iron
discs at a distance of a few inches from its circumference these few inches of
the outer extremity of the wheel are thus left flat for the magnets to be secured
to it.
The cast iron distance piece is of somewhat larger diameter than the bosses S
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
or bolted together being still further strengthened by angle pieces placed between
the discs and the cones.

page_text: Each magnet consists of a cylindrical iron core of two bobbins of brass or other
metal containing wire and of two pole pieces. The core passes through a bole in
the flat portion of the revolving disc formed by the two wrought iron discs and
ring near its outer circumference and is fixed so as to project equally on both sides
3 of such disc. The brass bobbins are then slipped on one at each side of the disc
and when the pole plates are fixed on the extremities of the cores they hold_the
bobbins in their places The pole plates are of iron preferably wrought. Two
of the planes bounding them are radial to the magnet wheel and they are made
a little shorter than the fixed coils and about two thirds the width of a fixed coil.
The shaft runs in bearings preferably of phosphor bronze which are carried on
low standards on the top of the sole plate.
A large gap or opening is made in the sole plate 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 placed on the shaft and pressed
gently against the inside ends of the phosphor bronze journals by means of set
screws projecting from the ends of the cast iron bosses.
These set screws are secured by lock nuta. The collars also carry the contact
rings 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 vul-
canite or other insulator. Brushes press on them in the ordinary way and convey.
a current to them.
The fixed coils are carried by rings of cast iron. The fixed rings are supported
by being bolted to the inside of the gap in the sole plate and by four cast iron
5 struts from the top of the low standards on the sole plate. They are also tied
together by tie rods.
Each fixed ring is made in three segments one being much smaller than either
of the other two.
The reason for this is that if a fixed coil should break down the power of the
O machine is only diminished by the loss of that coil and therefore the broken coil
can be left till there is a convenient opportunity to take the machine to pieces but
if a revolving coil breaks down it must be repaired at once before the machine
can be worked. By removing the small segmental piece from one of the fixed
rings and turning the wheel till the damaged coil comes to the opening thus
5 made it is rendered accessible without the necessity of taking the machine to
pieces.
The cores of the fixed coils are wedge shaped and consist each 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.
AT piece with a wedge shaped head is inserted into one end of the folded plate
and welded to it the stem of the T piece is screwed and passed through a hole
in the fixed ring and is secured by lock nuts. The stem of the T piece need not
be permanently fixed onto the head but may be screwed into it from the back of
the fixed ring.
A wooden block is slipped on to the core and secured by one or more pins. The
block forms the back flange.
A German-silver flange is rivetted on to a shoulder cut on the end of the core
near the revolving wheel. If slits are made in this flange then in addition to
such slits a cut is made passing completely through into the opening of the core.
Projecting lugs are cast on the German silver flange which dip into the opening
in the core and prevent the slit in the flange from opening. The flange may be
further secured by being made to project beyond the wire of the bobbin at its
outer extremities and being secured to the wood by long screws and distance pieces.
The screws must of course be inserted after the wire is wound.
The exciter may be any suitable machine giving a direct current.
The Drawings annexed shew various views of a dynamo machine containing the
above described improvements.

page_text: 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 8. 9 and 10 full sized
views of one of the magnets.
The machine represented in the Drawings is intended to be driven direct from
the steam engine without belt or other multiplying gear. The revolving wheel is
8 feet in diameter at the magnet centres. The sole plate is 13 feet 4 inches long 1
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.
A are its two central discs and B the two cones whose bosses 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.
D is the cast iron distance piece by which the discs A are kept apart at the
centre. At the rim they are kept apart by the 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 discs are rivetted with double butt strips the cones with single ones. The
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.
Near the edge of the discs and wrought iron ring E holes are formed equidistant
from each other and from the axis-a cylindrical bar G₁ of soft iron is passed right
through each hole so that it is parallel to the axis and projects equally from each
side of the disc. One method of securing the soft iron cores G' in the holes is
shewn at Figures 9 and 10 The central part of the core is made larger than its two
ends and has a screw thread cut around it to screw into a corresponding thread cut
in the hole. When the core has been adjusted in position it is locked and prevented
from turning by a small screw G* screwing into a hole drilled partly into the core
and partly into one of the discs A or by centre punching round the edges of the
hole other means of securing the cores in the holes might however be adopted.
A brass bobbin G³, wound with insulated copper wire is slipped on to each
projecting end of the iron core and is held on by an iron plate G³ fixed on the end
of the core and forming a pole piece. The way in which it is fixed to the end of
the core is clearly shewn at Figure 9-other ways of fixing it might however be
employed.
The wire coils of the several bobbins are connected together so that a current
from a separate small direct current machine called the exciter may be sent
through them all so that the iron cores are converted into electro magnets. The
bobbins are so connected that the end of a bar on one side of the disc has an
opposite polarity to the other end on the other side and that on the same side of
the disc the ends of the bars have N and S, polarities alternately. Each pair of

page_text: half bars projecting from either side thus forms a horse shoe electro magnet of
which the disc forms the " yoke."
The shaft C runs in bearings preferably of phosphor bronze they are carried by
low standards H which stand up from the sole plate I.
1 is a large gap or opening in the sole plate I through which a portion of the
wheel dips into a pit below the machine.
K. K. are the two loose iron collars for taking the thrust they are placed on the
shaft are prevented from revolving on it by means of a loose feather and are
pressed gently against the inside ends of the phosphor 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 shown 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'. M³, and by the four
cast iron struts M². They are also tied together by the seven screwed rods M.
Each fixed ring is as hereinbefore stated made in three segments one being much
smaller than either of the other two. Preferably the small segment is at the top
as shown at Figure 1.
The fixed rings may if preferred have a hollow or channelled section through
which water can be circulated to keep them cool.
64 fixed coils are fixed to each ring so that 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 described in the before mentioned Specification No 5536
in the year 1881,
The details of the fixed coils are shown on a larger scale in Figures 6. 7. and 8.
N is a wedge shaped core consisting 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 locks nuts 01.
P is a wooden block slipped onto the core and secured by one or more pins.
Qis a German silver flange 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 Q', are cast on the German
silver which clip into the opening in the core and prevent the slot Q' from
opening. The flange may be further secured by being made to project beyond the
wire in places Q and being secured to the wood by long screws and distance
pieces. These screws must of course be inserted after the wire is wound.
The T pieces may also be made with a removeable stem which may be screwed
in through a hole in the fixed ring from behind and screwed into the head.
R. R. represent the holding down holta.
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 the construction of the revolving wheel of dynamo machines the
combination of the two discs A, distance piece D ring E electro-magnets & coned
bosses F and coned plates B substantially as described.
Second. The combination of the ring E the iron cores G³ projecting from either

page_text: side of it the bobbins G³ slipped onto each iron core and the pole pieces G³,
substantially as described.
Third. The construction of the sole or bed plate of dynamo machines with a
gap through which a portion of the wheel descends into a pit below substantially
as described.
Fourth. The combination with the boss of the revolving wheel of loose iron
collars pressed outwards from the boss by screw studs to cause them to bear lightly
against the sides of the bearings in which the axle of the wheel is carried
substantially as described.
Fifth. The combination of the bed plate I with the slot or gap I¹ therein the
fixed rings M bolted to the inside of the gap I¹ the tie rods M³ the low standards H
carrying the axis of the revolving wheel and the struts from the top of the
standards or from the sole-plate being with or without the low standards H in
case the axle is or is not sufficiently high above the sole-plate to cause them to bo
required substantially as described.
Sixth. The construction of the fixed rings M which carry the induction bobbins
each in three segments one much smaller than either of the other two substantially
as and for the purpose herein before described.
Seventh. The construction of the cores of the fixed coils of T pieces with wedge
shaped beads and stems that may or may not. be permanently fixed to such heads
such heads being welded into V shaped pieces formed of iron plate bent to an
acute angle substantially as described.
In witness whereof I the said James Edward Henry Gordon have hereunto
set my hand and seal this fifteenth day of December in the year of our Lord
One thousand eight hundred and eighty two.