IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES AND IN THE METHOD OF CONSTRUCTING THE ARMATURES THEREOF
Year: 1884

page_text: We, THOMAS PARKER, and PAUL BEDFORD ELWELL, both of Commercial Road,
Wolverhampton, in the county of Stafford, electrical engineers, do hereby declare
the nature of our invention for IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES
AND IN THE METHOD OF CONSTRUCTING THE ARMATURES THEREOF to be as
follows:-
Our improvements relate to those parts of the above machines known respectively.
as armatures, brush holders, and magnets.
An armature frame constructed according to this invention is made of a series of
vanes or flat arms formed with or fixed to a central boss mounted upon a spindle.
These vanes radiate from the centre like those of a fan and their outer edges are
straight and parallel with the spindle. In order to give the desired length of
armature frame, without the inconvenience of forming vanes the whole length of
the frame, two or more sets of vanes may be fixed upon the spindle with the vanes
of one set butting respectively against those of another set so that the outer edges
of the corresponding vanes of each set may form continuous edges parallel with the
spindle. An iron core is formed upon these vanes by winding iron wire around
them as around a cylinder, or by slipping over the frame a series of sheet iron
rings. When iron wire is wound on, as aforesaid, then, in order to prevent the
flatness of the coils between the edges of the vanes which would arise from
attempting to coil the wire upon the skeleton frame, and in order to give the coil a
true cylindrical shape, blocks of wood, (or other suitable material) having their
surfaces turned up to complete the cylindrical surface, are inserted between the
vanes and held in position by discs of wood (or other suitable material) screwed to
their ends. After the wire has been coiled upon the cylinder formed by the
exterior surface of the wood and the edges of the vanes, the wood is removed.
This construction of armature frame and core, and whether the core is formed of
wire or of sheet iron rings, admits of perfect mechanical truth and thoroughly
substantial fixing, and allows of running within the pole pieces with the least
possible clearance, thus increasing the intensity of the magnetic field.
armature also has the great advantage of allowing a draught of air to pass through
between the arms or vanes and thus keep itself from heating. The radiating parts
of the commutator bars may be constructed to assist in producing this draught
The insulated copper wire is wound longitudinally inside and outside the iron core,
such winding being effected in an even number of coils connected together as
follows:-The first coil wound is connected at the commutator end to a second coil
of from 90 to 120 degrees in advance thereof and these coils are also connected to
The

page_text: a commutator bar. The second of these coils is connected at its back end to the
back end of a third coil at the opposite point in the circumference of the armature.
This last-mentioned coil is connected at the commutator end to a fourth coil
opposite to the first mentioned coil, and these third and fourth coils are connected
also to a commutator bar. The back end of this fourth coil is connected to the
back end of a fifth coil immediately in advance of the first coil, thus forming the
commencement of another series of coils which are connected as in the case of the
series of four coils first-described. This method of winding is continued throughout
any number of series, and the end of the wire is finally connected to the wire
commencing the first coil, thus forming the whole of the coils into a continuous
conductor. By this method of winding the armature, the polarization experienced
in the ordinary "Gramme" ring, and which is due to the current flowing in the
armature and generating poles in the ring at right angles to the poles of the
magnetic field, is got rid of; and the current flowing in our improved armature
tends to produce poles to assist the field, thereby greatly reducing the tendency to
heat and raising considerably the duty of the machine. In large diameter
armatures the length of useless wire is also materially reduced.
A brush holder constructed according to this invention has a part to which the
brush itself is rigidly fixed connected simply by means of a thin horizontal web to
a part which is rigidly fixed to the framing or other fixed part of the machine.
A portion of that part to which the brush is fixed direct is connected to a portion
of the part fixed to the framing by means of an adjusting screw, and by the
operation of this screw the end of that part to which the brush holder is fixed may
be drawn towards or pushed from the rigidly fixed part, the thin web between
these parts yielding elastically and thus acting in lieu of a hinge. This web
connection in combination with the adjusting screw keeps the brush exactly in
position against the commutator bars, and does not allow it to follow any
irregularities therein as in the case where the brush is pressed against the bars by
a spring. The advantage of this arrangement is that any irregularity in the bars
is gradually corrected by the wearing down in a true cylindrical form of the
exterior surfaces of the whole series of bars. This employment of the thin web in
lieu of a hinged joint also avoids the looseness incidental to the hinged joints and
the risk of bad electric connection.
The magnets constructed according to this invention are made of single slabs of
wrought iron bolted together so as to form a rectangular frame around the armature
of the machine. One of these slabs forms the base, two of the slabs are fixed
vertically thereon, and the remaining slab joins together the top ends of the vertical
slabs. All the slabs are of course fixed flatways to the armature. The bottom slab
projects beyond the vertical slabs to form snugs or feet for fixing it to the bed of
the machine, and magnetic insulating blocks are placed between these feet and the
bed, and magnetic insulating bolts are employed to fix the bottom slab. The cast
iron pole pieces, which are attached preferably to the top and bottom slabs
respectively, have each a large number of wrought iron pins passing through them,
and through the slabs to which they are respectively connected, in close contact
with the metal of such pole pieces and slabs so as to obtain the superior magnetic
qualities of wrought iron, in combination with the lesser cost of cast iron for the
chief bulk of the pole pieces. The two side magnets and parts of the top and
bottom magnets (that is on each side of the pole pieces fixed thereto) are wound to
obtain the magnetic system and thus secure a great length of solenoid. This
construction of magnets is very simple, efficient and compact.
.
Dated this 5th day of January 1884
J. C. MEWBURN,
Agent for the Applicants.

page_text: We, THOMAS PARKER, and PAUL BEDFORD ELWELL, both of Commercial Road,
Wolverhampton, in the County of Stafford, electrical engineers, do hereby declare
the nature of our invention for IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES
AND IN THE METHOD OF CONSTRUCTING THE ARMATURES THEREOF and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement reference being had to the accompanying
drawings and the letters of reference marked thereon.
Our improvements relate to those parts of the above machines known respectively
as armatures, brush-holders, and magnets.
Figure 1 of the accompanying drawings is a longitudinal section through a
dynamo-electric machine, Figure 2 is a section taken on line x x of figure 1, and
figure 3, is a half plan thereof.
A A is the armature frame, and consists of a series of vanes or flat arms a a etc.
formed with or fixed to a central boss B which is itself formed with or fixed to
the spindle C. These vanes a a have their outer edges straight and parallel with
the spindle, as shewn. In the armature illustrated it will be seen, by figure 1, that
the whole length of armature frame is formed of two sets of vanes, with the vanes
of one set butting respectively against those of the other set, so that the outer
edges of the corresponding vanes of each set form continuous edges parallel with
the spindle. The vanes are, however, electrically insulated between their butting
edges as shewn at a¹ a¹ figure 1. An iron core is formed upon these vanes by
winding iron wire around them as around a cylinder, or by slipping over the
frame a series of sheet iron rings. An iron wire core is shewn in section figure 1,
and for a part of the distance only along the armature, for convenience of drawing.
When the iron wire is wound on, as aforesaid, then, in order to prevent the flatness
of the coils between the edges of the vanes which would arise from attempting
to coil the wire upon the skeleton frame, and in order to give the coil a true
cylindrical shape, blocks of wood (or other suitable material) having their surfaces
turned up to complete the cylindrical surface, are inserted between the vanes and
held in position by discs of wood (or other suitable material) screwed to their ends.
This provision for winding on an iron core is illustrated by figures 4 and 5, of
which figure 4 is a longitudinal section through the armature frame with the
wooden blocks properly fixed therein, and figure 5 is a section on line y y of
figure 4. A¹ A¹ etc. are blocks of wood inserted between the vanes a a etc. so as to
forin therewith a true cylindrical surface. D D are discs of wood screwed together
by pins b b b so as to retain the blocks A' A' etc. in position. c c etc. (shewn by
dotted lines figure 5) are tennons on the ends of the blocks A¹ A¹ etc., entering
within corresponding mortices in the discs D D. E E are metal plates or bushes
carrying the discs D D upon the spindle C. d d (see also figures 1 and 2) are
washers of vulcanized fibre or other insulating material carried immediately inside
small lugs or projections e e etc. (see also figures 1 and 2) on the outer ends of the
vanes a a etc. Strips of insulating material are laid also along the edges of the
vanes, upon which the wire is to be wound. After the wire is coiled upon the edges
of the vanes for the desired thickness, and for the whole distance between the
washers d d, the discs D D and the wooden blocks A¹ A¹ etc. are removed, and the
armature is ready to receive the conductor coils.
The above method of winding an iron wire core is very convenient, but any
convenient method may be adopted,

page_text: This construction of armature frame and core, and whether the core is formed of
wire or of sheet iron rings, admits of perfect mechanical truth and thoroughly
substantial fixing, and allows of running within the pole-pieces with the least
possible clearance, thus increasing the intensity of the magnetic field.
The armature also has the great advantage of allowing a draught of air to pass
through between the arms or vanes, and thus keep itself from heating. The
radiating parts ff of the commutator bars (figures 1 and 3) assist greatly, in
consequence of their rapid rotation, in producing a draught through the vanes of
the armature; and this action of the radiating arms is improved by the addition of
an annular disc of insulating fibre or other suitable material fixed around the
outer face of the radiating parts. The direction of the air current is indicated by
the arrows, figure 1.
The insulated copper wire is wound longitudinally inside and outside the iron
core in any convenient manner in which armatures of the Gramme-ring type may
be wound, but a peculiar method for effecting the winding of this armature, and
which is applicable generally to armatures of the Gramme-ring type, is illustrated
by figure 6 of the accompanying drawings, in which A A is the iron core of the
armature and B B the commutator cylinder. This figure, as alsó figures 7 and 8
next to be described, is drawn to a larger scale than the other figures, for the sake
of clearness of illustration. Referring now to figure 6: Assuming the winding
to commence at the coil 1, the wire is first passed backwards across the outside of
the ring, and so on around the ring until a sufficient number of laps are wound.
The wire is then carried across the back of the armature, as shewn by broken
lines a a, to 2, where it is first brought forwards across the outside of the ring and
a second coil wound thereon. The wire is then passed, as shewn at b b, to 3, and
is thence passed backwards across the outside of the ring and a third coil wound
thereon, the wire from thence passing, as shewn by broken lines c c at the back of
the armature, to 4, when a fourth coil is wound. The wire passes similarly from
thence, as shewn by d d to 5, where a fifth coil is wound, from thence, as shewn by
broken lines ee at the back to 6, where a sixth coil is wound, from thence, as
shewn by ff to 7, where a seventh coil is wound, from thence, as shewn by broken
lines g g at the back to 8, where an eighth coil is wound, thus completing one series
of coils around the ring. The wire is carried from coil 8 across the front, as shewn
at a a¹, to 21, where the first of a second series of coils is wound, and from thence
at the back of the armature to 11, from thence at the front to 41, from thence at
the back to 31, from thence at the front to 6', from thence at the back to 51, from
thence at the front to 8¹, from thence at the back to 71, and from thence, across
the front, back to the starting point at 1, where the open ends of the wires are
connected to complete the circuit. Each of the connectors across the front of the
machine are connected to a commutator' strip C C etc, as shewn at h³ h' etc.
many series of coils as convenient may be wound in this manner, the last of the
last series of coils being connected to the first of the first series, as described. The
second series of coils is shewn to be laid beside the first series, but the wires of one
series of coils may be made to alternate with those of another series, if preferred.
As
A brush-holder constructed according to this invention is illustrated by figures 7
and 8, of which figure 7 is a vertical section through a brush-holder, and figure 8 a
section taken on line z z of figure 7. This brush-holder is carried by the framing
of the machine according to the usual or any convenient manner. According to
the illustration, the part g corresponds to the bar or carrier g figure 1.
G is a
part, therefore, connected rigidly to the framing of the machine. G₁ is a part
forming the brush-holder proper. h is a thin web of metal formed solid with, and
therefore connecting together, both the parts G and G. H is a thumb-screw
through the part G, and is geared by means of collars to the part G¹. As the
screw His turned, the top end of the part G is drawn towards or pushed from the
part G, the web h between these parts yielding elastically and thus acting in lieu
of a hinge. This web connection, in combination with the screw H, keeps the
brush exactly in position against the commutator bars, and does not allow it to
11

page_text: follow any irregularities therein, as in the case where the brush is pressed against
the bars by a spring. The advantage of this arrangement is that any irregularity
in the bars is gradually corrected by the wearing down, in a true cylindrical form,
of the exterior surfaces of the whole series of bars. This employment of the thin
web, in lieu of a hinged joint, avoids the looseness incidental to hinged joints and
the risk of bad electric connection. The screw J is for holding the brush in the
part G', and the screw K is for the circuit-wire connection.
The magnets, constructed according to this invention, for a dynamo-electric
machine, are made of single slabs of wrought iron K K¹ L L' (figures 1, 2, and 3)
bolted together so as to form a rectangular frame around the armature of the
machine. The slab K¹ forms the base and the slab K the top, and these two slabs
join together the ends of the slabs L and L', as shewn. The slab K¹ projects at
each end beyond the slabs L and L', as shewn, and these projecting ends act as
feet by which the whole framing formed by the slabs is bolted down to the bed M M
of the machine. N N are magnetic insulating blocks between these projecting
parts and the bed; and the bolts 0 0, which hold the magnets to the bed, are
inade of non-magnetic metal. P and P¹ are soft iron pole-pieces, and are attached
preferably to the slabs K and K¹, respectively. These pole-pieces, if made of cast-
iron, have each a large number of wrought iron pins k k etc. passing through them
and through the slabs to which they are respectively connected, such pins being
driven tightly into their holes so as to be in close contact with the metal of the
pole-pieces and slabs and thus obtain the superior magnetic qualities of wrought
iron in combination with the lesser cost of cast iron for the chief bulk of the pole-
pieces. R R' are plates of iron covering the outer ends of the pins k k etc.
plates are to increase the mass of metal. Screwed pins, not shewn on the drawing,
pass through the plates R R¹ and slabs K K¹ into the pole-pieces P P¹ to hold these
parts together. S S and S¹ S¹ are strips of wrought iron filling in between the
projecting ends of these plates and the pole-pieces P P¹, as shewn. The two side
magnets L L, and those parts of the top and bottom magnets K K¹ which are on
either side of the pole-pieces P P', are wound to obtain the magnetic system and
thus secure a great length of solenoid. This winding is shewn on one side of
figure 2. The outline of the coils around the magnets, where such coils are not
shewn in full, is indicated by broken lines figures 2 and 3, shewing such coils to
come at their ends about flush with the ends of the pole-pieces. The bow T is
simply for the purpose of facilitating the lifting of the machine.
These
The construction and arrangement of magnets as above described is very efficient
and compact.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is :-
1. Armatures, for dynamo electric machines, constructed with a framing formed
of a number of metal vanes or flat arms upon which a cylindrical iron wire core is
wound in any convenient manner, or upon which a core is formed by means of
sheet iron rings, substantially as and for the purpose herein described and shewn
by figures 1, and 2, of the accompanying drawings.
2. The employment of blocks in combination with an armature frame constructed
in the manner referred to in the foregoing claim, upon which blocks and frame
an iron core, when of wire, is wound, and the blocks thereafter removed,
substantially as and for the purpose herein described and shewn by figures 4 and 5
of the accompanying drawings.
3. In a dynamo-electric machine having an armature constructed in the manner
substantially as herein before described, an annular disc ? placed on the outside of
the radiating arms of the commutator bars, substantially as and for the purpose
herein described, and shewn by figures 1 and 3 of the accompanying drawings.
4. In a brush-holder for a dynamo-electric machine, the combination of a thin
web of metal connecting together the part of the holder fixed to the main framing

page_text: of the machine and the part of such holder in which the brush is held, with an
adjusting screw or equivalent means for adjusting the position of the brush in
relation to the commutator strips, substantially as and for the purpose herein
described and shewn by figures 7 and 8 of the accompanying drawings.
5. In a dynamo-electric machine, forming the magnets of flat slabs and arranging
and fixing them to form a rectangular frame around the armature of the machine,
substantially as and for the purpose herein described and shewn by figures 1, 2,
and 3 of the accompanying drawings.
6. In a dynamo-electric machine, the employment of the wrought iron
pins etc. in combination with cast-iron pole-pieces, substantially as and for
the purpose herein described and shewn by figures 1, 2, and 3 of the accompanying
drawings.
Dated this 10th day of September 1884