Improvements in the Field Magnets of Dynamo-electric Machines.
Year: 1891

page_text: Date of Application, 30th Dec., 1891-Accepted, 30th Jan., 1892
COMPLETE SPECIFICATION.
Improvements in the Field Magnets of Dynamo-electric Machines.
We, LAZARUS PYKE and EDWARD STEPHEN HARRIS, Electrical Engineers,
of 34, New Tothill Street, in the City of Westminster, 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:-
.
These improvements relate to that class of dynamo-machines, in which the field
inducing wire consists of or acts as a single coil.
We then
We surround the said coil with a cast, forged or otherwise shaped mass of
magnetic material on its inner and outer circumference and on one face, said
magnetic mass extending on its open face beyond the edge of the coil.
close the said face, except at a narrow zone sufficient for the rotation of the
armature or inductors, by placing on and in the said extensions of the magnetic
mass nicely fitting flat annular lamina, arranged so as to form a continuation of
the field magnet and provided with such polar extensions or projections, as may be
desired.
This invention may be used in machines for the production of single or many
phase alternating, or for continuous currents, the polar extensions or projections and
the induced current conductors being readily arranged for any desired disposition
(in the case of inductor machines being so arranged, that the induced current
conductor may be wound on the polar projections).
We prefer wrought or good cast iron for the solid field magnet, and fine soft
iron for the lamina, which may be shaped by punching, cutting or in other
convenient manner.
any
The lamine should be rigidly fixed to one another and to the field magnet; we
prefer bolts through punched holes clear of the polar projections for the former,
and a key or keys for the latter purpose.
The shaft may pass through the centre of the field magnet, and have the inductor
or armature carrier on one side, while the pulley is on the other side of the field
magnet.
The field magnet forging or casting may have feet or projections forming part of
the magnetic mass and serving to fix the same or to form a bed-plate.
The drawings hereto annexed illustrate a dynamo electric machine embodying
our invention, and constructed in accordance with our Patent No. 11,503 of 1888.
Fig. I is a vertical section.
Fig. 2 is an end view, the right half being shown with the inductors, and the left
half without the inductors. The left half shows also some of the polar projections
without the secondary coils.
Figs. 3 and 4 show the laminated rings and polar projections on a larger scale.
Fig. 5 is a perspective view of an inductor, also on a larger scale.
Fig. 6 is a section and Fig. 7 a face view of one of the reels carrying the
secondary coils.
B represents the magnetic mass forming an annular space for the inducing coil
and enclosing the latter on three sides.
D is the inducing coil, supplied with current from an exciting dynamo or other
suitable source.
R and R' are the outer and inner laminated rings fitting into the said annular
space and provided with polar projections a, a, b, b. As shown by Figs. 3 and 4,
the lamina are held together by bolts and secured to the magnetic mass by keys.
F and G are reels of vulcanized fibre or other suitable insulating material
mounted on the polar projections and carrying the secondary coils f, g, which are
connected with each other and the terminals according to the desired effect.

page_text: C is the inductor carrier mounted on one end of the driving shaft S.
Jare laminated inductors, half as many as there are polar projections on each
ring; they are secured to the carrier by bolts.
Sis the driving shaft supported by the magnetic mass and carrying at one end
the inductors, while to the other end is fixed the driving pulley P. s are screw nuts
for securing the inductor carrier in position.
As indicated by Fig. 1, the shaft S is lubricated by means of a longitudinal
groove, which is supplied from a lubricator L through an oblique passage 1. The
faces of the magnetic mass B have oil cups, which are drained into a recess O
through oil ducts l'.
T are a pair of terminals, o is a draw-off cock for waste oil, d are feet or lugs for
bolting the magnet B to a bed-plate.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :
1. In a dynamo-electric machine, a field magnet composed of:
a, an electric conductor formed of or acting as a single inducing coil,
b, a single mass of magnetic material, surrounding the said coil on one face,
as well as on the inner and outer circumference, and extending at its
extremities beyond the coil, combined with
c, a number of flat rings of magnetic metal fitting in and on the said extensions,
so as to form continuations of the field magnet, and provided with polar
projections or extensions, as may be required.
Dated this 30th day of December 1801
L. PYKE.
E. S. HARRIS.
By Fairfax & Wetter,
433, Strand, London, Agents.