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Патент USA US2134795

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NOV. 1, 1938.
-
T, G, MYERS
2,134,795
MAGNETIC STRUCTURE FOR DYNAMO-ELECTRIC MACHINES
Filed July 14, 1956
INVENTOR
The as G)- Myers
[3% W
/
ATTORN EY
2,134,795
Patented Nov. 1, 1938
UNITED STATES PATENT ‘OFFICE
2,134,795
MAGNETIC STRUCTURE FOR DYNAMO
ELECTRIC MACHINES
Thomas G. Myers, Los Angeles, Calif., assignor
to U. S. Electrical Motors, Inc., Los Angeles,
Calif., a corporation of California
Application July 14, 1936, Serial No. 90,556
6 Claims. (Cl. 171-206)
'This invention relates to magnetic structures
for dynamo-electric machines, such as for in—
stance, the stators of induction motors.
The stator structures for such motors are usu
5 ally made up of a series of slotted soft steel or
mixing the binder and the powdered magnetic
material prior to molding the sticks out of the
composition. The solidifying of the sticks can
vbe accomplished in the ordinary way, dependent
upon the kind of binder used.
When a phenolic
iron punchings, which are held compactly to
condensation product is used, the intermingled
gether by appropriate fastening means, such as
mass is subjected to heat and pressure in a mold,
rivets.
in a manner utilized for molding Bakelite.
This invention possesses many other advan
It is well understood that such lamina
tions in a direction axial of the motor, serve to
10 reduce eddy current losses which may become
tages, and has other objects which may be made 10
more easily apparent from a consideration of
one embodiment of the invention. For this pur
pose there is shown a form in the drawing accom
performance of the motor, it has been proposed ' panying and forming part of the present specifi
to provide slots that are closed or nearly closed. cation. This form will now be described in de 15
tail, illustrating the general principles of the in
Under such circumstances, it is necessary to in
sert the windings or coils a few wires at a time vention; but it is to be understood that this de
tailed description is not to be taken in a limiting
through the slots. Such a procedure is expen
sive; and could not be effectively utilized for any sense, since the scope of this invention is best de
excessive unless this mode of construction is used.
The windings for the stator are accommodated
in the slots. In order to improve the efliciency or
except motors that operate under comparatively
low electromotive forces, such as 400 volts.
For
higher electromotive forces, such as for 2200 volt
operation, the insulation must be heavy and the
coils form wound, precluding the possibility of
25 this endwise insertion.
In order to obtain the advantages of closed
slots, it has been proposed to use laminations
having open slots into which the winding can be
easily placed, and then to close the slots by a
30 magnetic stick. Such a construction however
has been found disadvantageous, for the eddy
current losses in the sticks reduce the e?iciency
of the motor, and in fact may cause excessive
heating of the sticks.
35
40
It is one of the objects of this invention to
make it possible to utilize any form of winding
in the stator slots, without the necessity of using
loose wound coils, and yet obtain the advantages
of closed slots without excessive eddy current
losses.
'
,
It is another object of the invention to improve
and simplify in general the magnetic structures
for dyanmo-electric machinery.
It is still another object of the invention to pro
45 vide magnetic top sticks for closing the slots,
made in such fashion that the eddy-current loss
is reduced to an immaterial amount.
In order to attain this object, the top sticks
are made up of ?nely divided magnetic material,
50 such as iron or soft steel, held together by a non
metallic binder, such as a phenolic condensation
product. The binder serves not only to hold the
stick in shape, but to insulate the magnetic par
ticles or groups of particles from each other.
56 This effect can be produced readily by thoroughly
?ned by the appended claims.
Referring to the drawing:
Figure 1 is a fragmentary pictorial view of a
top stick embodying the invention; and
Fig. 2 is a fragmentary sectional diagram of a -
magnetic structure embodying the invention.
25
. The top stick I can be made from a composition
of from six to ten parts powdered iron or soft
steel or other magnetic material, and about one
part of resin or other non-metallic binder.
These proportions are by weight. The ingredi 80
ents in powder form can be ?rst thoroughly
mixed, and then molded by heat and pressure to
the desired form.
'
The sticks l are shown in Fig. 2 as closing the
slots 2 of the stator 3. The stator windings 4 35
are merely diagrammatically illustrated. The
stator structure is shown as cooperating with a
rotor structure 5 of the cast squirrel cage type.
The top sticks I may be provided with the
sloping side wings 6 adapted to enter into the
corresponding recesses ‘I near the top of. slots
2; thereby the sticks are locked against radial
movement.
The sticks l are intended to be slipped or in
serted in place from the end of stator magnet
structure 3. This structure 3 may also be made
up of a homogeneous mixture of a non-metallic
binder and magnetic powdered material, such as
iron or soft steel, in about the same proportions
as used for the sticks I. This makes it possible
to mold or form the stator magnet as a single
piece, and with a consequent reduction in the
eddy current loss; and yet obviate the neces
sity of punching out numerous sheet steel discs
and the slots therein. The punched, out, wasted 55
2
2,134,795
portions in this former construction constitutes
about one third of the steel blanks, corresponding
to corners of the squares, and the winding slots.
What is claimed is:
'
1. A pre-formed top stick for closing the slot
in a magnetic structure for dynamo-electric ma
chines, made from a homogeneous mixture of di
vided particles of magnetic material and a non
metallic binder, and adapted to entirely close the
10 slot.
2. A magnetic structure for dynamo-electric
machines, made from a mixture of divided par
ticles of magnetic material and a non-metallic
binder, in the proportion of about seven parts
15 by weight of the magnetic material and one part
by weight of the binder.
3. A top stick for closing the slot in a mag
netic structure for dynamo-electric machines,
made from a mixture of divided particles of mag
20 netic material and a non-metallic binder, in the
proportion of about seven parts by weight of the
magnetic material and one part by weight of the
binder.
4. A molded magnetic structure for dynamo
electric machines, made from a mixture of di
vided particles of magnetic materials, and a
phenolic condensation product, in the proportion
of about seven parts by weight of the magnetic 6
material and one part by weight of the phenolic
condensation product.
_5. A pre-formed top stick for closing the slot
in a magnetic structure for dynamo-electric ma
chines, made from a homogeneous mixture of di 10
vided particles of magnetic material and a phenolic
condensation product, and adapted to entirely
close the slot.
6. A molded top stick for closing the slot in a
magnetic structure for dynamo-electric machines, 15
made from a mixture of divided particles of mag
netic material and a phenolic condensation prod
uct, in the proportion of about seven parts by
weight of the magnetic material and one part by
weight of the phenolic condensation product.
THOMAS G.‘ MYERS.
20
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