Improvements in the Construction of Dynamo Electric Machines and Motors.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Construction of Dynamo Electric Machines
and Motors.
I, MATTHEW WILLIAM WALBANK MACKIE, 77, Turnmill Street, London, E.C.,
Electrical Engineer, do hereby declare the nature of this invention to be as
follows:-
The object of this invention is to construct an electric dynamo machine or
motor having as short a magnetic path & using the least amount of material
as possible in its construction. With this object in view I may mount the
field magnet core upon the driving shaft & wind it with a magnetising coil or
coils, upon both ends of this core as well as over part of the coil. I may fix
the discs which are to form the armature core & then wind over it the armature
The leading
wires & connect the same in the usual manner to a commutator
in wires being lead from the field magnet coil or coils are connected to insulated
terminal rings & connected in the circuit. I now enclose this armature and field
magnet in an iron or other suitable magnetic metal case having projecting
pieces so formed as to become inductors or keepers or stationery magnetic poles
concentrating the magnetic lines of force produced by the internal magnet &
leading them up & through the armature wires at one end of the armature then
diagonally across and partly round the circumference of the armature then
down & through another proiecting inductor or pole piece at the other end of
armature & thence through the armature wires & discs & thus completing the
magnetic circuit by this means I can produce as many magnet poles as I desire
with one exciting coil only. Or I may construct the machine so that the
exciting field magnets coils are stationery by winding this coil or coils so that
the armature complete is free to revolve inside it and letting this coil in a
recess formed between the projecting inductor or pole pieces of the case.
It may be advisable in constructing this armature to let the wires into slots
cut into the discs. The winding on this armature may be of any of the well
known windings provided that the number & position of the wires relatively
correspond with the number & position of my inductor pole pieces as they would
do if the machine was constructed with the usual stationery magnets but I pre-
fer to wind this armature across the. face of the discs then across one end of the
armature to its correct position corresponding to its position for the succeeding
magnet pole & thus backward & forward right round the armature thus placing
the effect of the inductor poles upon the armature wires in series with each
other thus obviating any necessity for cross connections or multiple brushes
besides allowing all the wires to be formed & all practically connected together
before they are placed in their positions on the armature.
By rearranging the winding of the wires on the armature an alternating
current machine or motor will be produced.
ail. Joy of 1808
MATTHEW WILLIAM WALBANK MACKIE.
[Price 8d.].

page_text: Improvements in the Construction of Dynamo Electric Machines
and Motors.
I, MATTHEW WILLIAM WALBANK MACKIE, of No. 77, Turnmill Street, in the
City of London, Electrical Engineer, do hereby declare the nature of this inven-
tion and in what manner the same is to be perforined, to be particularly
described and ascertained in and by the following statement:-
This invention relates to improvements in the construction of dynamo-electric
machines and motors, and the primary object of it is to shorten the magnetic
path and to reduce the amount of material now employed in the construction
of these machines for any given output, but without diminishing either their
efficiency or their output as compared with the best machines at present known.
By efficiency I mean their percentage return in electrical energy, for the dynamic
or mechanical energy expended to drive them or vice versa according to whether
the machine is employed as a generator or dynamo or as a motor; and by output
I mean, say, the number of lamps of a certain power it will supply or the
amount of "work" it will do. Thus a machine constructed according to my
present invention for a given output would be considerably more compact, that
is, less in dimensions and weight than the best of machines at present known
constructed for the same output.
The following is a description of my invention with reference to the accom-
panying drawings which illustrate as an example a dynamo-electric machine
and modifications of some of the component parts thereof, but it must be clearly
understood that although this dynamo-electric machine is shewn suitably
wound for a continuous current, nevertheless my invention is not thereto limited,
for by simply changing the windings and effecting other slight modifications
according to the well-known practice, it would be converted into an alternating
current machine, and by supplying either the continuous current or alternating
current dynamo with electricity from an external source to drive it, it would be
converted into either a continuous or alternating current motor accordingly.
In the accompanying drawings:-
.
Figure 1 is an end elevation of a dynamo or motor constructed according to
my present invention.
Figure 2 is a central vertical section through the dynamo or motor.
Figure 3 is an inverted plan of the top half of the inductor or keeper.
Figure 4 is a central vertical section of a modified form of the armature.
Figure 5 is an inverted plan of a modified form of the pole-pieces of the
inductor, and
Figure 6 is a further modified form of the inductor pole-pieces.
Figure is a sectional elevation of the field magnet core plates as used when
the said core is to be laminated.
Throughout these drawings like reference letters refer to different views of
the same parts.
With the above objects in view I mount the field magnet core a upon the
driving shaft b and wind it with a coil or coils c (or I may omit this coil or
coils altogether and use the coil B only or both combined) and upon both ends
of this core a as well as over part of the coil c (if such coil be used), I fix the
discs d which are to form the cores of the armature, and then wind over them
and right across, the armature wire or wires A; and connect the same in the
usual manner, to a commutator E', the leading-in wires f f being led from the
field magnet coil or coils c to collector-rings E, E and connected in the circuit.

page_text: The armature and field-magnet thus constructed and combined are enclosed
in or surrounded by an iron or other suitable magnetic case G. This case in
combination with the magnet core a and discs d is a special feature of the in-
vention for shortening the magnetic field.
It is a solid cylindrical body or mass of metal surrounding the field-magnet
and armature cores and their windings or coils, and it has on its internal sur-
face: two or more projecting pieces g, g', g², g³, arranged at intervals diagonally
opposite each other so as to interspace each other, and so formed as to become
inductors, keepers or stationary magnetic poles.
"This magnetic case G which is hereinafter referred to as the inductor, may be
made all in one piece and mounted or fixed upon the bed-plate of the machine;
or it may be built up of two or more sections for convenience of handling when
very large machines are required; but at present I have found it quite sufficient
to construct it in two parts only, h and has shewn in Figures 1 and 2, semi-
cylindrical or thereabouts in form, one being the complementary part of the
other to form a complete cylinder. Integral with such complementary part
cylinder is the bed-piece or base i upon which the machine stands. These
two halves h h of the inductor Gare or may be bolted or otherwise firmly held
together by suitable fastenings and thus form an immovable case or sta-
tionary shell entirely surrounding the armature and field magnet. The above
: arrangements may be slightly modified if desired by constructing the machine
so that the field magnet exciting-coil is stationary, by winding this coil com-
plete in itself and inserting it in a recess & formed between the projecting pole-
pieces 9, 9, 92, 93, of the inductor G, in such a way that the arinature com-
plete will be free to revolve inside it. The coil B in Figure 2 may represent
such a coil. Alternatively, the inductor and exciting-coil may be made rotat-
able and the armature and field-magnet core stationary!
The winding on the armature may he according to any of the well-known
types or methods of winding, provided only, that the number and position of
the wires relatively correspond with the number and position of the special
inductor pole-pieces as they would do if the machine were constructed with the
usual stationary magnets.
I prefer, however, to wind the armature in a direction mainly parallel with
its axis, that is to say, across the face of the discs d thence across one of its
ends to its correct position corresponding with its position for the succeeding
magnetic pole and so on backwards and forwards entirely around and across the
armature, thus placing the effect of the inductor poles g, g', g², g³, upon the
armature wires A in series with each other, and thus obviating any necessity
for cross connections or multiple brushes, besides allowing all the wires to be
formed or bent into shape and all practically connected together before they
are placed in their position upon the armature. By re-arrangement of the
winding of the wires upon the armature in a well-known manner as above
stated an alternating current dynamo-electric machine or motor will be produced.
I would here remark that some advantage may be gained in constructing the
armature by letting or inserting the wires in slots cut into the discs.
Reverting to the field magnet core a, its form may be as shown in Figures 1
and 2, or it may be formed as shewn in Figure 4 with horns or lateral projec-
tions for the armature core to rest upon, or it may consist of laminations of
plates, of the form shewn in Figure 7, or it may even be built of iron
wire, the ends of which may be turned up between the discs of the armature
core so as to make the magnetic connection between these wires and the said
discs or core.
The coil B (Figure 2) may also be taken as representing a special coil which
may appropriately be called the divertor-coil. It serves the double purpose of
exciting the magnet core and at the same time diverting, rebutting or turning
back the stray magnetic lines which will attempt to pass in the direction indi-
cated by the double-arrow heads (see Figure 2) and will prevent them passing

page_text: in that direction or by that path and consequently, they having to find some
other path or way, will naturally pass in a circuit through a course indicated
by the single-arrows, as more fully described hereinafter.
The field magnet exciting-coil may be wound on each of the. projecting pole-
pieces of the inductor G instead of merely lying or resting between them as
shewn, or in other suitable ways.
The operation of the machine as a dynamo-electric machine arranged for
continuous current is as follows:-
The field-magnet core being mounted on the driving shaft and the armature
being mounted and completed as previously described, they revolve together
within the magnetic casing or inductor GF, which is itself stationary. The
field-magnet coil may be excited from quite an independent source, or it mar
be excited by part of the current produced by the machine itself, or by partly
the one and partly the other as desired.
The field-magnet having been excited, the field of magnetic lines of force
is created. The inductor G also becomes magnetised, and by its pole-pieces re-
acts in such a manner as to concentrate these magnetic. lines of force and lead
them up to and past the armature wires at one end of the armature, thence
diagonally across and partly round the circumference of the armature, thence
down and through another projecting pole-piece of the inductor at the other
end of the armature, thence down to and past the armature wires and down
through the discs etc., thus completing the magnetic circuit.
By this means I can produce as many magnet poles as I desire, with one
exciting coil only, and by the employment of the divertor coil B the magnetic
field produced yields a greater per-centage of useful magnetic lines of force
than would otherwise be obtainable.
The armature wires revolving and cutting the lines of force, will have induced
in them the usual electro-motive force tending to set up a current, but by
studying the effect on one wire during its course of part of its revolution, it will
be found that as it approaches and passes under an inductor on the right-hand
side, an E. M. F. will be induced in part of the wire immediately under the
influence of the inductor and in one direction, and when the same wire approaches
and passes under an inductor on the left-hand side an E. M. F. will be in-
duced in the opposite direction as in the case of an ordinary machine when wire.
passes from one magnetic pole to another, but it will be noted that the armature
discs or core never have their magnetism reversed as is the case in the ordinary
machines, and I therefore save a certain amount of energy usually lost in the
said core.
The current thus produced is led away to the outer circuit containing the lights
or other "work," by means of the usual brushes from the commutator rings or
cylinder. For the purpose of minimising or reducing the Foucault currents
produced in the armature wires and discs, it may be advisable to taper the
polar area of the pole-pieces of the inductor, as shewn in Figure 5, or it may be
grooved or indented as shown in Figure 6.
In a groove in the pole-pieces I insert a metal bridge piece H to form a guard
to prevent any foreign matter getting into the armature proper.
By suitably constructing and extending these guards H, so as to enclose the
whole machine, I may make the same water-tight for traction purposes.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, I declare that what I
claim is
1. A dynamo-electric machine or motor characterised by having the field-
magnet core mounted fast upon the driving or driven shaft and revolving with
it, the armature mounted fast upon or around both ends of the field-magnet
core and revolving with it, a stationary magnetic metal case with pole-pieces
surrounding the armature and field-magnet core.complete, and an exciting and

page_text: divertor coil within said case, substantially as and for the purposes described
and set forth.
2. A dynamo-electric machine or motor, constructed and working substan-
tially as described and illustrated in Figures 1 and 2 of the accompanying
drawings.
3. In a dynamo-electric machine or motor the combination with the driving
or driven shaft of a field-magnet core mounted fast upon said shaft and revolv-
ing with it, and wound with an exciting coil adapted to receive an electric
current from any convenient source, and an armature core mounted fast upon
or around the ends of said field-magnet core and revolving with it and wound
according to any well known type of winding, substantially as and for the pur-
poses described and set forth.
4. In a dynamo-electric machine or motor, the combination with the driving
or driven shaft, of a field-magnet core mounted fast on said shaft and revolving
with it, and wound with an exciting coil, an armature mounted fast upon or
around both ends of said field-magnet core and revolving with it, and a sta-
tionary magnetic-metal case with pole-pieces surrounding or enclosing the com-
bined armature and field-magnet, substantially as and for the purposes described
and set forth.
5. In a dynamo-electric machine or motor, the combination with the magnet
core and discs, of the stationary magnetic-metal case or inductor with two or more
pole-pieces projecting from the internal surface arranged diagonally opposite
and interspacing each other, substantially as and for the purposes described and
illustrated.
6. In a dynamo-electric machine or motor, the combination of the stationary
magnetic-metal case or inductor having two or more pole-pieces projecting from
the internal surface arranged diagonally opposite and interspacing each other
with a coil or coils of wire located within the central space between the said
pole-pieces, as described.
7. A dynamo-electric machine or motor characterised by the field-magnet
exciting coil being wound complete in itself and located in a recess formed in a
stationary magnetic-metal case surrounding the complete armature and field
magnet core, substantially as described and set forth.
8. A dynamo-electric machine or motor having a field magnet core fixed to the
main shaft and revolving with it and having its poles on the axle of the said
shaft, these poles being extended radially by means of armature discs upon and
across which are wound the armature wires, and surrounded by an energizing
coil whose axis is concentric with the magnet, the whole being enclosed in or
surrounded by a magnetic-conducting case with inductor pole-pieces suitably
placed at each end of the said case, substantially as hereinbefore described.
9. The general arrangement and combination of parts constituting a dynamo-
electric machine or motor, substantially as herein before described and illustrated
in the accompanying drawings.
PHILLIPS & LEIGH,
•
No. 22, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.