Improvements in or relating to Dynamo Machines.
Year: 1892

page_text: Date of Application, 21st June, 1892
Complete Specification Left, 15th July, 1892-Accepted, 20th Aug., 1892
PROVISIONAL SPECIFICATION.
Improvements in or relating to Dynamo Machines.
I, CHARLES JAMES HALL, of 207 Hyde Park Road, Leeds, in the County of
York, Electrician, do hereby declare the nature of this invention to be as
follows:-
This invention relates to improvements in the construction of the field magnets
of certain kinds of dynamo machines, and they are especially applicable to the
kind of dynamo machine described in the application for Letters Patent dated
24th day of September 1891, No. 16250, in the names of Robert Hammond, and
Charles James Hall-the applicant hereto.
In the case of revolving field magnets, having several poles, two iron discs are
securely mounted upon the rotatable main shaft of the machine, and adapted to
hold between then a number of laminated iron plates. These plates are each of a
U form, and a number of them assembled together, and suitably excited, constitute
the field magnets of the machine. They are usually and conveniently stamped
out of sheet metal with the limbs rectangular in outline and slightly radiating,
according to the diameter of the field magnet system and number of poles used.
The yoke portion of each plate is preferably formed as a segment of a circle, and
it has two bolt holes formed in it, whereby the assembled plates are bolted
together. The plates are arranged to break joint with each other, so that when a
sufficient number are assembled together in their proper alternating order, they
constitute a complete ring with its radial poles, and in this form they are bolted
between the two discs previously mentioned, and turn with them and the shaft.
Near the polar ends of the plates a groove is formed on each side of each limb,
and these grooves coincide throughout all the plates. When the coil windings
are placed on each limb or pole, a brass cap, preferably cast in two pieces, is fitted
on the end of each pole piece to retain the winding in place, and being formed with
a longitudinal tongue to fit in the corresponding groove in the plates the cap is
securely held in position. The two halves of the brass cap are then secured
together by bolts, rivets, or other suitable means, and the cap is thus effectually
held against centrifugal action when the magnets are revolving.
Dated this 21st day of June 1892.
FAIRFAX & WETTER,
433, Strand, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in or relating to Dynamo Machines.
I, CHARLES JAMES HALL, of 207 Hyde Park Road, Leeds, in the County of
York, Electrician, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement :-
This invention relates to improvements in the construction of the field magnets
of certain kinds of dynamo machines, and they are especially applicable to the
kind of dynamo machine described in the application for Letters Patent dated
24th day of September 1891, No. 16250, in the names of Robert Hammond, and
Charles James Hall-the applicant hereto.
In the further description of this invention, reference is made to the accom-
panying drawings in which Fig. 1 is a face elevation of a system of field magnets
adapted to revolve, in which the right hand half of the figure represents the

page_text: exterior view with the magnets wound with a suitable electric conductor or
conductors, and with a brass cap on each polar end; and the left hand half of the
figure is a vertical section showing the unwound cores in their relative positions.
Fig. 2 is a vertical section taken transversely through Fig. 1; Fig. 3 is an
elevation, and Fig. 4 is a plan of the brass cap previously mentioned.
In the drawings, a is a suitable shaft adapted to rotate in bearings in any known
manner, are two iron discs securely mounted upon the shaft a in any convenient
manner and turning with it. The discs have a number of holes drilled through
them (near the periphery) at regular distances apart to receive transverse bolts or
studs which have suitable nuts. A series of iron plates d of a U shape are
formed with two bolt holes in the yoke portion of each plate. These holes
.correspond in size and position to bolts e, so that the plates may be assembled
together (preferably insulated) and clamped between the discs by the said
bolts and nuts c to form the laminated core of the field magnets. A wrought iron
ring is placed on each side, outside the plates d, and securely bolted between the
said plates and the discs by the bolts c. These rings tend to keep the plates in
position, and distribute strains evenly.
The plates d are usually and conveniently stamped out of sheet iron with the
limbs rectangular in outline and slightly radiating, according to the diameter of
the field magnet system and number of poles adopted. The yoke portion d' of
each plate is preferably formed as a segment of a circle, with two bolt holes
(previously mentioned) whereby the assembled plates are bolted together. The
bolt holes are conveniently situated upon the intersections of the centre lines of
each limb with that of the yoke d'. The plates dare alternately arranged so as
to break joint with each other, and when a sufficient number' are assembled
together in their proper order (as shown on the left hand half of Fig. 1), they
constitute a complete ring with its radial poles, and in this form they are bolted to
and between the two discs by the bolts c (as previously mentioned) and turn with
them and the shaft.
By arranging the plates alternately in the manner described, there is not only
the advantage of forming a complete ring of sectional plates, but also that of
leaving air spaces between the central part of the yoke d' of the several plates.
thus tending to keep the magnet cores cool.
be as
Near the polar ends of the plates d a groove 2 is fortned on each side of each
limb and these grooves coincide throughout all the plates. When the coil
windings e are placed on each limb or piece of the assembled plates d, (as shown
on the right hand half of Fig. 1), a brass capfis fitted on the end of each pole
piece to retain the winding e in place. The brass caps fare preferably cast in two
pieces and of such a form (when fitted together) as to leave a long rectangular
opening (as shown in Fig. 4) which will just fit over the ends of the assembled
plates forming a pole piece. Each brass cap consists of a flat plate with
strengthening ribs on one face of the plate. The rib at each end
long as the full width of the plate (as shown in Fig. 4) but upon the sides, the
ribs are formed or cut away from the inner edge to correspond with the depth
of the side grooves d² of the magnet plates d, and the inner portion of the cap/,
which forms the sides of the rectangular opening, being of a suitable thickness, they
form longitudinal tongues to fit into the corresponding grooves d² of the assembled
magnet plates d. The two pieces forming a capf being thus fitted in place, they
are riveted or otherwise secured together at g and effectually are held-together
with the winding e-against centrifugal action when the magnets are revolving.
may
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is ;-
1. In a dynamo machine, a system of field magnet cores consisting of a series
of Ushaped plates assembled together alternately to form a combined
ring with radial poles and combined with and driven by a rotatable shaft and

page_text: connecting discs, substantially as and for the purpose herein described and
illustrated.
2. A rotatable field magnet system composed of a series of U shaped plates
each plate having two holes formed therein and bolted together alternately to
leave air spaces at the central portion of the yoke, combined with a non-magnetic
cap fitted upon the polar ends of an assemblage of the said plates to retain a
suitable winding in place, substantially as and for the purpose herein described
and illustrated.
3. A laminated magnet core consisting of an assemblage of iron plates each.
plate being of a U form, the yoke portion being formed as a segment, of a circle
with two holes formed therein, and each plate having grooves at the polar end of
each limb, substantially as and for the purpose herein described and illustrated.
4. In a dynamo machine, the combination of a shaft with two discs mounted
thereon, an assemblage of U shaped plates alternately placed and bolted together
by transverse bolts to and between the said discs, a suitable coil winding on each
limb of the said plates, and a brass cap fitted on the polar ends of the plates, sub--
stantially as and for the purpose herein described and illustrated.
Dash: 15th of T..1.. 1900
FAIRFAX & WETTER,
433, Strand, London, Agents for the Applicant..
FAIRFAX & WETTER,
433, Strand, London, Agents for the Applicant..