Improvements in Electric Motors.
Year: 1891

page_text: Date of Application, 10th Mar, 189'-Accepted, 9th May, 1891
COMPLETE SPECIFICATION.
[Communicated from abroad by THE GIANT ELECTRIC MOTOR COMPANY,
of 27, School Street, Boston, Massachusetts, United States of America.]
Improvements in Electric Motors.
I, HENRY HARRIS LAKE, of the firm of Haseltine Lake & Co. Patent
Agents 45 Southampton Buildings, in the County of Middlesex, 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 electric motors of the multipolar type and is an
improvement upon the invention described in Letters Patent No. 7867 May 20th
1890.
The said invention consists in certain novel features of construction, arrangement
and combination of parts which will be hereinafter described with reference to the
accompanying drawings in which
Figure 1 is a vertical longitudinal section of an electric motor illustrating my
invention, taken on line 11 of Figures 2 and 3.
Figure 2 is a sectional elevation taken on line 2, 2, of Figure 1, looking towards
the right of Figure 1.
Figure 3 is a vertical section on line 3 3 of Figure 1 and showing the armature
in elevation.
Figures 4 and 5 are respectively a plan and an end view of a pair of laminated
field magnet cores or hole pieces.
Figures 6 and 7 are respectively a plan and an end view of the coil of wire and
its flanged sleeve to be fitted upon each of said cores, and
Figure 8 is a section of the flanged sleeve on line 4 4 of Figure 6 with the coil
of wire removed.
Like letters of reference indicate corresponding parts in the several figures.
In the drawings A and A' are the end frames of the machine connected together
by means of the base plate B and the tie girt B.
C is the armature shaft mounted in bearings A2 and A³ and having firmly secured
thereon at a point equidistant from the two frames A and A' the hub D of the
amature as shown in Figure 1. The frames A and A' are provided with the
inwardly projecting annular ribs A4 and A5 respectively, upon which are secured
by suitable bolts, the field magnet cores E E.
These field magnet cores E are made in pairs composed of a series of thin plates
laid one above another with a sheet of paper between each two plates, each plate
forming a section of two cores and a connecting tic as shown in Figures 4 and 5.
These plates which form the field magnet cores are shown as curved concentric to
the axis of revolution of the armature, but they may be bent so as to occupy portions
of three flat planes each tangent to a circle concentric to said axis of revolution as
indicated by dotted lines a a a in Figure 5, in which case the outer surfaces of the
ribs A and A³ would be made up of a series of flat surfaces to fit the inner surfaces
of said cores.
The pole ends of the field magnet cores E E are curved to arcs of circles for their
entire widths the axes of which circles are in planes cutting said cores longitudinally
through the centres of their widths as shown in Figure 4, so that the motor will
operate equally well with the armature revolving in either direction.
The field magnet cores extend inward from the frames A and A¹ in positions
parallel to the shaft C, and are each provided with a coil of wire wound
preferably upon a removable spool or flanged sleeve F¹ composed of a paper tube a
and the fibre flange & made up by winding a ribbon of heavy paper around a form

page_text: having the same cross section as the core E till about three thicknesses are laid one
upon the other and secured together by glue or other adhesive material then
slipping upon said tube the two fibre flanges of the desired thickness one near each
end of said tube, and then turning outward the end portions of the outer layer of
the paper tube a, and securing such turned out portions to the outer surfaces of the
flanges by glue or other adhesive material as shown in Figures 7 and 8.
These flanged sleeves F¹ with the coil of wire F thereon are slipped upon the
cores E and secured in position by the pins cc and may be readily removed for
renewal or repairs.
The armature is composed of the hub D, the disc like flanges G and G', the
series of radially projecting core supports d composed of vulcanized fibre and
secured to said flanges the series of armature cores e e and the coils of insulated
wire fall constructed, arranged, and operating in precisely the same manner as
described in said before cited prior Patent.
H is the commutator, constructed substantially like the commutator shown and
described in the aforesaid Patent No. 7867 of 1890. I is one of the brush holders;
J is the stud or arm for supporting the same and K is the segmental plate clamped
to the bearing A³ and having secured thereto the studs J, all constructed and
arranged substantially as in said prior Patent.
The armature coils are connected together in groups and to the commutator, and
the field magnet coils are connected together in series in precisely the same manner
as described in the said Patent.
Joints in a magnetic circuit increase the resistance of that circuit to the lines of
force which are expected to pass, and set up consequent poles at the point of
juncture.
Two adjacent cores in my improved motor are included in a magnetic circuit,
and by doing away with the joint by making the two cores as one piece, I avoid the
free magnetism which in the old form was a considerable loss.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed as communicated to me by
my foreign correspondents I declare that what I claim is :-
First. In a multipolar motor a series of field magnet cores constructed and
arranged in pairs, the two cores in each pair being placed parallel to the axis of
revolution of the armature and connected together in one piece but removed from
contact with the cores of the next magnet and having their pole ends curved
tangentially to a plane at right angles to the axis of revolution in both directions
from the centre of the width of each of said cores.
Second. In a multipolar motor a series of field magnet cores constructed and
arranged in pairs, the two cores of each pair being composed of a series of plates
placed one above another and each forming a part of each core, and being placed
parallel to the axis of revolution of, the arinature but removed from contact with
the cores of the next magnet and having their pole ends curved tangentially to a
plane at right angles to the axis of revolution in both directions from the centre of
the width of each of said cores.
Dated this 10th day of March 1901
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.