Improvements in and relating to Electric Motors or Dynamo Electric Machines.
Year: 1899

page_text: Date of Application in the omted Kingdom, on Apr., 199
Complete Specification Left, 15th Apr., 1899-Accepted, 29th July, 1899
Improvements in and relating to Electric Motors or Dynamo
Electric Machines.
I, ROBERT LUNDELL, of No. 527, West 34th Street, New York, United States
of America, Electrician, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement :-
My invention relates to improvements in electric motors or dynamo electric
machines and its objects are :-
First, to construct an electric motor or dynamo electric machine having a field
magnet frame consisting of a laminated body portion and provided with brackets
for holding the laminated portion together with end brackets which act as journal
bearings for the armature shaft:
Second, to construct an electric motor or dynamo electric machine having a
laminated body portion provided with brackets for holding the laminated parts
together, with end brackets and doors for admitting free access to the interior of
the motor :
Third, to provide an electric motor or dynamo electric machine with simple
and efficient means for holding the field magnet coils thereof in position and
also for causing the magnetic flux to gradually diminish toward the pole corners:
Fourth, to provide an electric motor or dynamo electric machine with a brush
holding device which securely holds the brushes and freely admits of adjust-
ment of the same, in such manner that the supporting shank thereof may
always be adjusted in a plane parallel with the diameter of commutation on the
commutators:
Fifth, to provide an electric motor or dynamo electric machine with special details
of construction hereinafter referred to.
For a clear understanding of the invention, reference is made to the accompanying
drawings, in which,
Figure 1 is an end elevation of the motor, partly in section, the upper left hand
section being taken on the centre line X X and the lower on line Y Y of Figure 2.

page_text: Figure 2 is a side elevation of the motor with its upper left hand corner shown in
section on centre line Z Z of Figure 1.
Figure 3 shows in elevation, one of the soft sheet iron laminated portions of
which the entire field magnet is built up for the purpose of obtaining the highest
possible magnetic permeability. These laminated portions are hereinafter referred
to as "field punchings."
Figure 4 is a side view of one of the pole pieces and coil holders: and,
Figure 5 is a sectional view of the same holder, taken on the centre line x x of
Figure 4.
Figures 6 and 7 are detail views of the brush-holder, showing the novel manner
in which the same is held in position.
Said
It will be seen that the motor is of four pole type and with both ends alike.
The armature A is furnished with two windings and two commutators C, abso-
lutely alike, one commutator only being shown. The field magnet frame proper
consists of a number of sheet-iron punchings P built up between two end-
brackets B B so as to constitute the laminated body portion of the motor.
end-brackets are of strong construction and are furnished with feet and journal
bearings as may be required. They have each a large circular opening (concentric
with the armature) in which the journal bearing brackets EE and doors D D are
fitted, the journal bearing brackets being secured to the end-brackets BB by
bolts F F F and the doors being held by spring catches S S S.
The field coils G G are secured in their positions by the polar extensions H H,
which are wedge-shaped and furnished with grooves or catches a a at their lower
ends, engaging equivalent catches b b upon the field punchings or with other suitable
devices. They are further secured in position by right and left hand screw-jacks KK,
two for each set of polar extensions, which jacks rest in oblong holes c c in the faces
of the polar extensions (see Figures 4 and 5) and are locked in position by wires
extending through their centre portions. The field coils may be wound a trifle small
so that the wedge-shaped polar-extensions may bug them tightly, after they are
forced in position. These polar extensions form another important function. They
are made from such material (preferably cast iron) that their magnetic permeability
is only about one-half of that of the pole-centre or field magnet proper, whereby
they cause the magnetic flux to gradually diminish toward the pole corners, even
though the armature cross-magnetizing force would have a tendency to abnormally
increase the strength of one of the pole corners.
Figures 6 and 7 show the brush-holder in detail. Two of these holders are used
for each commutator and are symmetrically arranged on each side of the centre
line Z Z (see Figure 1) one being shown in dotted lines on the right hand side. The
construction of this brush-holder is similar to the one shown and described by me in
a prior Patent No. 13477 of the year 1898 but a novel clamp for holding the same in
position constitutes a part of the present improvements.
This novel clamp consists of an eyebolt L which passes between two ribs M M¹ of
the casting and which is secured in position by the nut N. The shank V of the
brush-holder which is clamped between said eyebolt and ribs is square in section and
is surrounded by an insulating vulcabeston sleeve V₁, also square in section, so that
there is no danger of the brush-holder turning. This clamping eyebolt L being
provided, as it is, with a rectangular opening and an extended portion passing through
an opening in the side of the machine at E together with a nut N permits the
shank V and its surrounding insulating sleeve V₁ to be held firmly or securely
against the edges of the two internally projecting ribs M M', in such manner as to
permit of the vertical adjustment of the parts in a plane parallel with the diameter of
commutation on the commutators, as will be clearly appreciable on inspection of
Figures 6 and 7 of the drawings.
I do not limit my improvements to the particular details of construction herein
shown and described, as it is obvious that a number of such details may be applied to
motors other than those having laminated body portions.

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is :-
1. A field coil holder for dynamo electric machines, consisting of a wedge-shaped
polar extension between the coil and its core substantially as described.
2. A field coil holder for dynamo electric machines or motors consisting of a
core, and secured in
wedge-shaped polar extension between the coil and its
place by the groove and catch or by other suitable means substantially as
described.
3. The combination with the field core of the wedge-shaped polar extensions of
high magnetic reluctance extending along the sides of the said core for the purpose
of holding the coil in position and also for reducing the magnetic flux at the pole
corners, substantially as described.
4. A clamp-for-a-brush holder-consisting of an eye bolt and an insulating sleeve
adapted to be held by-suid-eye bolt between two-stationary ribs, substantially-as
described.
3. A brush-holder having a metal supporting shank surrounded by a
substantially-square-insulating-sleeve-and-clamped in a holder which permits the
shank-to-be-adjusted in a plane-parallel with the-diameter of commutation-on-the
commutators.
6. 4. An electric motor constructed substantially as described with reference to the
accompanying drawings for the purposes specified.
ated this 15th day of April 1893.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.