IMPROVEMENTS IN MAGNETO- ELECTRIC MACHINES
Year: 1881

page_text: LETTERS PATENT to Henry Francis Joel, of Dalston, in the County of
Middlesex, Civil Engineer, for an Invention of "IMPROVEMENTS IN MAGNETO-
ELECTRIC MACHINES."
PROVISIONAL SPECIFICATION left by the said Henry Francis Joel at the
Office of the Commissioners of Patents on the 21st October 1881.
HENRY FRANCIS JOEL, of Dalston, in the County of Middlesex, Civil Engineer.
"IMPROVEMENTS IN MAGNETO ELECTRIC MACHINES."
My Invention relates to structural improvements in magneto electric machines
constructed on the Paccinotti principle, whereby they are rendered less costly
in construction and maintenance, and the force of the generated current is
improved.
My improvements are essentially in the construction of the frame, the field
magnets, the armature, the commutator, and the brushes and frames, and further,
in the novel disposition of the magnets relatively to the armature, and in the
method of connection between the armature coils through the commutator.
In my improved frame I mount upon an iron base two upright standards, one at
each end, upon which I fix the field magnets. In the centre of the supporting
standards I leave a gap in which a plummer block is fixed to carry the axle of the
revolving armature so that it may be easily taken out when desired without
disturbing the rest of the machine.
The class of field magnets I employ are preferably made in separate parts for
greater ease of manufacture and repair.
The revolving armature I construct in eight or many distinct sections, of which
the iron cores are made of small plates joined together so as alternately to overlap,
and when fitted they form two separate and distinct iron rims or wheels of flat
surface. Each of these sections is wound separately with insulated wire, and when
fitted are attached to radial spokes with special cheeks of iron. These cheeks bind
and fix the sections together so as to make a complete ring armature of eight or
many coils interfaced with iron cheeks of which the outer faces are grooved for
better access of the air and for concentration of the magnetism on the edges.
Dis 37

page_text: The armature is also made hollow so as to allow a free passage for the air to the
interior of the coils.
The commutator I construct of separate pieces of metal of step shape, with their
centres of narrow width which fit into grooves cut in a ring of some insulating
material. These pieces are fixed parallel with the axle of the machine, and are
disposed in a ring with the sides rabbeted or cut down. One side receives the
screws for fixing the pieces, whilst the other receives similar screws for attaching
the wires. Each part is made interchangeable and easily fixed or removed, whilst
the whole commutator can be quickly taken off the axle of the machine.
I may modify this form of the commutator by using the metal pieces in three
or more steps to suit the different arrangements of coils.
The brushes and holders I construct so as to be operated in a single frame. I
attach them to the top of the machine, and so construct them that whilst the
brushes and holders can be easily taken apart the whole is adjustable as in one
piece by set screws and a rack and pinion action.
In my novel disposition of the field magnets relatively to the armature I arrange
the pole-piece plates of the field magnets on opposite sides of the armature to
overlap one another in their paired position so as to "make and break" three or
more times across the magnetic field.
may alternatively arrange these pole-pieces in sets of four, a north and south
pole being on each side of the armature, or I may use two poles only in a set,
wholly north on one side of the armature and wholly south on the other.
In this latter case I arrange the central or neutral point of the north pole-piece
above or below the same point of the south pole-piece on the opposite side of the
armature, in the direction of rotation to prevent electrical equilibrium; the iron base
plate forms the neutral point.
In my improved method of connection between the armature coils through the
commutator I use eight or other convenient number of coils divided into two
circuits, each circuit being distinct. I arrange the commutator so as to make eight
or other suitable number of breaks during one revolution. Each system of coils is
thus alternately alone in connection with the main system. At all other portions
of the revolutions the two systems are combined in parallel circuit, the extra
qurrent made from the break in the circuits being arranged to help the main
current.
The change takes place when the isolated system of coils, i.e., those not in
connection with the main system, are almost neutral.
I may alternatively arrange the two rims of the armatures to be connected
together magnetically instead of being isolated from one another.
I also utilize my improved form of commutator so as to shunt the coils in the
main circuit, which are not in use, to a separate wire of high resistance wound
round the field magnets in the method advocated by Wheatstone.
And further, by the same means and a combination of two or a number of
collecting brushes, I arrange that two or any number of the coils may be cut out as
desired.
I also arrange by my improved commutator to connect the high resistance
magnet coils across the breaks in the commutator.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Henry Francis Joel in the Great Seal Patent Office on the
21st April 1882.
HENRY FRANCIS JOEL, of Dalston, in the County of Middlesex, Civil Engineer.
"IMPROVEMENTS IN MAGNETO ELECTRIC MACHINES."
My Invention relates to improvements in magneto electric machines whereby
they are rendered less costly in construction and maintenance, and the force of the
generated current is improved, and especially to that class of magneto electric
machines which produce continuous currents by the aid of special commutators as
distinguished from magneto electric machines which produce alternating currents
or currents of constant direction and power.
My improvements are essentially in the construction of the frame, the field
magnets, the revolving armature, the commutator, and the brushes, and frames;
and further, in the novel disposition of the magnets relatively to the armature, and in
the method of connection between the armature coils through the commutator.
And in order that my said Invention may be fully understood I now proceed
more particularly to describe the same, reference being had to the Drawings
hereunto annexed, in which like letters refer to like parts in corresponding
Figures: The letters N and S and n and s always representing north and south
magnetic poles.
Figs. 1 and 2 show front and side elevation respectively of one form of my
improved dynamo machine.
I mount upon an iron base plate A two upright standards B, one at each end,
upon which plummer blocks bare fixed to carry the axle of the revolving
armature so that the armature may be easily taken out when desired without
disturbing the rest of the machine.
Upon the base plate A I mount four upright field electro-magnets C, braced
across the top by the iron plate a.
In this type of my machine I arrange the said magnets C in pairs with the
wire so coiled as to make the north and south poles of each pair in the centre of
the magnets and opposite to one another, as shown at N and S. To these poles
I attach extending pole plates n, s, shown in detail in Figs. 3, 4, 5, and 6, herein-
after more particularly specified.
The revolving armature I show in detail in Fig. 7 a half front elevation, Fig. 8
a plan, Fig. 9 a vertical section, and Fig. 10 a horizontal section. This armature
I construct in eight or many distinct sections, D, D1, D2, D³, &c., though I find in
practice that in this type of my machine an odd number (preferably nine) best
answers my purpose. The cores consist of small plates E constructed in sets of
four, fixed together in parallel and opposite pairs (with a space between) each pair
being composed of two plates half overlapping (Fig. 9), and across the middle is
coiled the insulated wire G. A series of separately wound sections with projecting
ends is thus formed, and these sections are fitted one to the other in a continuous
double ring of iron cores E of flat surface, and the projecting ends of each section
alternately overlap and are attached to those of the next. All bolts f fixing the
opposite plates of the double ring must be of non-magnetic material, so as to
preserve the two sides in magnetic insulation. This construction is clearly shown
in Figs. 9 and 10. The ring thus formed is carried upon radial spokes F of
non-magnetic material, and the fitting screws f serve the double purpose of
attachment to the spokes and connection of the overlapping ends of the sections.
These coiled sections are interspaced by special iron cheeks e. These cheeks e
bind and fix the sections together so as to make a complete ring armature and

page_text: cover the heads of the smaller internal screws. They are constructed with a lip,
to bite the inside top faces of the exposed portion of the overlapping plates
and are secured to the spokes by the brass bolts f¹.
I have found that the strongest action obtainable from ring armatures with
projecting cheeks of my or other construction occurs when the projecting cheeks
make and break from the ends of the extending pole plates. I intensify this
action by arranging the pairs n, n', and 8, 8', of extending pole plates to alternately
overlap or be in advance of one another, as shown in Fig. 3.
In this case
the coil passing across the centre of the pole plates is at the moment of
passage comparatively neutral whilst at the same moment (in consequence of the
odd numbers) there is no neutral coil in front of the centre of the other poles.
This arrangement I have adopted in Figs. 1 and 2, where the armature is made up
of nine coils, and it enables me to cut out the coils singly and at alternate
poles in place of in pairs as hitherto practised in other machines, and thus to
minimize the neutral portion and avoid sparking at the commutator by the
decreased change of resistance from the single coil in place of the pair of coils
cut out.
Another modification of the extending pole plates that I may adopt is, by affixing
thereto or forming thereupon in pairs n, n', and 8, 8¹, projections, shown by dotted
lines in Fig. 5, and in profile in Figs. 4 and 6.
In this modification the neutral coils are cut out between the pole plates
(similarly to the position in the ordinary ring armatures), and not in the centre, as
specified in regard to Fig. 3, and the magnetic make and break takes place at or
near the centres of the pole plates. This construction I may apply to machines
with armatures made up of an even number of coils, or to armatures of ordinary
construction without projecting cheeks, and I may apply the projections on pole
plates in opposite pairs, and not overlapping or stepped.
By this construction of pole plates I have the advantage of the currents from the
induction action being added to the currents made from the magnetic make and
break.
My improved commutator I show in sectional elevation in Fig. 11, and in plan
in Fig. 12. It is constructed of separate pieces of metal H fitted on a ring of
insulating material J, shown black, stepped one on to the other in such manner as
to form a ring presenting alternately, as revolved, a solid or divided face. These
pieces H are fixed parallel with the axle of the machine, and have their sides
rabbeted or cut down. One of the rabbeted sides receives the screws for attaching
the wires, whilst the other allows for the screws, which fix the pieces to the axle.
Each part is made interchangeable and easy to be fixed or removed, whilst the
whole commutator can be quickly taken off the axle of the machine. In conjunction
with my commutator I may construct upon the same axle therewith a short
circuiting device, Figs. 12 and 13. This device, which will be more clearly under-
stood by reference to the diagrammatic Figure 23 (Sheet 2), consists of an indented
wheel h with the indentations filled with insulating material j, the whole mounted
on the ring J. This device enables me through a subsidiary brush or brushes / to
short circuit from the commutator through the exposed metallic portions at the
intervals of the insulating material occurring at the time of the increase
consequent on the cutting out of the neutral coil. The objects of this short
circuit will be hereinafter more fully specified.
In Figure 2 however it will be seen that I have not employed my commutator,
but that known as "
Varley's," consisting of a number of rings corresponding to
the number of single or double coils on the armature, with insulating spaces for
reversing and cutting out the bobbins as desired. The brushes K and holders L,
shown in Fig. 14, a front elevation, and 15, a plan, I construct so as to operate in
a single frame M. I attach them to the top of the machine (conveniently to the
brasses of the plummer block, as shown), and construct them in two halves, so that
the brushes and holders can be easily taken apart. I conveniently fit a handle Z
to enable me to move the whole round, and by means of a set screw at the foot

page_text: thereof to fix it in any desired position. The brushes are moved separately and
independently when desired by means of the rack m and pinion l.
The chief advantages I obtain by my before specified type of construction and
electrical arrangement, some of which are common to my modifications, are,―
Simplicity and economy of construction of the whole machine.
The disposition of the armature in an odd number of coils enabling me to cut
out a single coil in place of a pair of coils.
That all screws and holding bolts are across the centrifugal action, and have not
therefore any tendency to fly out during the rotation of the machine.
That the core plates and coil sections are detachably attached, thus offering great
facilities for repairs, and allowing the coils to be separately wound in a lathe.
That the built up construction of core plates permits their manufacture in small
pieces at a low cost by stamping.
That the double ring construction of armature not only offers the known
advantages of a hollow and ventilated core, but enables the double magnetic make
and break to be utilized to its fullest extent.
That the simplified construction of the commutator, brushes, and brush frame
afford facility for easy renewal and repair of parts.
A second type of my machine with a novel disposition of magnets relatively to
the armature is shown on Sheet II., the standards, frame, and field magnets are
however similar to those specified in relation to my first type, save that the field
magnets C, C, are arranged in opposite (n and 8) in place of similar (n and n or
8 and 8) pairs. These pairs (n and 8) are placed so as to alternately overlap or be
in advance of one another, as before specified in relation to the pairs n and n
or 8, 8), Fig. 3 (Sheet 1), or they are fitted with the alternative device specified
in relation to Figs. 4, 5, and 6.
Fig. 16 is a front elevation of the ring armature.
Fig. 17 is a section of the same.
Fig. 18 is a diagrammatic view of the complete armature and connections.
I now connect together the two rims E of the armature magnetically, instead of
isolating them from one another; but I preferably lay them flat, as shown, and
parallel to the axis. The rim is built up of sections with overlapping ends in a
similar manner to that adopted in the first type, or they may be solid rings. The
magnetic connection of the two rims is effected by iron bracing bridges e, e', which
interspace the coils, and bind and fix the sections together. Upon the radial non
magnetic supporting spokes and rim F, double rabbeted as shown, I support the
iron bridge pieces e which fit into the rabbeted rim, and are themselves rabbeted
on the top (seen clearly in Fig. 17). Upon these bridges I laterally slide the
double rim of overlapping sections, and clamp the whole together by the top
bracing bridge pieces e secured by the bolts P. Where it is desired to take out any
section, the removal of the bracing bridge piece which clamps it will leave it free
to be laterally slid out. The bridge pieces e and e¹ are shaped to project and
serve as cheeks to the rims. The wire is coiled upon the sections of the rims
independently, and those sections coiled in one direction are placed on one side of
the rim.
The connection between the armature coils and my special commutator H
(shown more clearly in Fig. 18) is made by wires g, each of which leads from
one commutator plate and is branched to the similar poles of a pair of the coils
G and G¹, one G on one side of the double rim, and the other G¹ on the opposite
side, but a coil in advance of the first named. I am enabled to adopt this method
of connection in series by my before described alternating arrangement of the pole
plates (or its alternative). The neutral portion of the bracing bridge pieces E, E¹,
occupies the place, and corresponds to the isolating space adopted in the first
described type of my machine.
The action of my second type of revolving armature and the paired arrangement
of the field magnets, and a special advantage derived therefrom, is the creation of
a magnetic field of great intensity, owing to the short distance between the opposite

page_text: poles N and S of the field magnets which are almost joined by the bridge pieces
E, E', and which consequently influence the wire on the circular rim to a much
greater extent than in the ordinary machines.
A third type of my machine is shown in Sheet II. Fig. 19 is a half elevation
of the revolving armature; Fig. 20 is a plan of the same; and Fig. 21 a section of
the same.
I now use two poles only of the field magnets in one machine, wholly north
on one side of the armature and wholly south on the other. The ends of the
extending pole plates presented to the armature are bevelled in a diagonal plane
(Fig. 20). The ring consists of but a single core built up of sections of my over-
lapping plates E and coils G. The overlap of the plates E is indicated in Fig. 19
by additional shading in the top section. Upon the radial non-magnetic sup-
porting spokes and rim F I fix the overlapping core plates by means of tooth
projections Q on the said rim F, and they are clamped in position by the bracing
bridge pieces e secured by the horizontal bolts f¹. These bridge pieces e are
externally indented, so that as they revolve they offer a sequence of edges to the
bevelled faces of the extending pole plates N, S, and thus make and break a
number of times. Any section may be laterally slid off by the removal of the
bracing bridge piece which clamps it.
A fourth type of my machine is shown in Figs. 22 and 23, which are a front
elevation and diagram respectively.
In this type of my machine I mount the field magnets in two sets of four poles
side by side, each set composed of two N and two S poles, paired N, N, and S, S,
(one set being clearly shown in Fig. 22). The pole extending plates overlap
(Fig. 23) as first described (or the alternative is adopted). The armature ring
consisting of coils wound on sections of overlapping plates is built up as specified
in reference to Figs. 1 to 10. In the improved method of connection adopted
between the armature coils through the commutator H, I use eight or other
convenient and even number of coils. These I divide into two distinct circuits
G and G. I construct the commutator in stepped pieces (as specified in reference
to Figs. 11, and 12, and 13) to make in one revolution a number of breaks equi-
valent to the number of coils. (The section of the stepped commutator is shown
for the sake of clearness in the diagram flattened or developed instead of in its
real position, which is cylindrical.) Each system of coils is thus alternately alone
in connection with the leading wires through the brushes K at the moment when
each of the latter is passing across one of the solid sections between the steps of
the commutator, as shown in the diagram. At all other positions in the revolution
the two systems are combined in parallel circuit, and the change takes place when
the system of coils not in connection with the leading wires is almost neutral.
In combination with the above I employ the auxiliary short circuiting device
already specified to connect up in a shunt circuit supplementary coils of wire R
coiled round the field magnets in a similar method to that advocated by
Wheatstone, or I lead the current through a separate leading wire to be utilized
as may be desired.
I may use subsidiary brushes k to make contact with the commutator plates in
circuit with the neutral system of coils G, to utilize the extra current from the
break in the circuit.
In any of the afore said types I find that I may magnetically insulate the sections
of coiled cores from one another without destroying their effect.
Each section of coiled core may be sub-divided into two or more sections of wire
coil, which may be connected in series or otherwise, as hereinbefore specified. The
projecting cheeks E need not invariably interspace every coil, but may occur at
alternate intervals.
My magneto electric machines in any of the types specified are applicable to all
the uses in which any known dynamo or magneto electric machines are of service,
such as for electric lighting, motive power, electro plating, &c.
And having now fully described and ascertained the nature and objects of my

page_text: Invention, and the manner in which it is to be performed, be it known that the
particular arrangements and parts which I claim as novel and desire to protect by
my Letters Patent are,-
1st. In magneto electric machines the construction of an annular armature core
built up of separate coiled sections, each section being made up of overlapping iron
core plates wound with one or more coils of wire, forming two distinct iron core
rings and complete armature, substantially as and for the purposes specified.
2nd. In magneto electric machines the stepping or overlapping of the field
magnet poles and the formation of projections thereupon to obtain many magnetic
nakes and breaks, substantially as hereinbefore specified, more particularly in
reference to Figs. 3, 4, 5, and 6.
3rd. The combination of a commutator constructed in step shaped pieces with
the subsidiary short circuiting device and the electrical connections, substantially
as and for the purposes hereinbefore specified in reference to Figs. 11, 12, 13,
and 23.
4th. The simplified construction of and combination of parts in the brushes and
holders, substantially as and for the purposes specified in reference to Figs. 14
and 15.
5th. In a magneto electric machine the construction of a double ring armature
(solid or built up in sections) coiled with insulated wire interspaced by iron
bridging pieces, the whole being in combination with field magnets in pairs of
reversed polarity, substantially as and for the purposes specified in reference to
Figs. 16, 17, and 18.
6th. The general construction and arrangement of my magneto electric machine,
and the combination therewith of the method of electrical connection of the coils
with the commutator, substantially as specified in reference to the diagramı,
Fig. 18.
7th. In my construction of magneto electric machine the peculiar arrangement
and combination of diagonally bevelled pole plates with indented armature
cheeks, substantially as and for the purposes specified in reference to Figs. 19,
20, and 21.
8th. In a magneto electric machine the combination of the sets of four poles
with the revolving armature, commutator, and electrical connections, substantially
as and for the purposes specified in reference to Figs. 22 and 23.
In witness whereof, I, the said Henry Francis Joel, have hereunto set my
hand and seal, this Twenty-first day of April, in the year of our Lord 1882.
HENR V
RANAN TAN
Witness,
JOHN C. FELL,
Fell and Wilding,
Patent Agents,
23, Rood Lane, E.C.
HENRY RANAN TAR