Year: 1899

page_text: I, BENJAMIN GARVER LAMME, of 230, Straiford Avenue, Pittsburg, in the County
of Allegheny, and State of Pennsylvania, U.S.A. Electrical Engineer, do hereby
declare the nature of this invention to be as follows: --
My invention relates to dynamo electric machines and has for its object to
improve various details of construction thereof. My improvements comprise
means for securing better ventilation than hitherto in machines, the iron cores
of which are built up of laminæ, and also devices for retaining in position the
coils or bobbins on the field-magnets of such machines. Incidentally I obtain
various advantages as regards lightness and uniformity of action of the machines,
but the main points which I have in view are the two above referred to, the
intention being to secure an especially simple and yet efficient construction.
In the drawing accompanying
Figure 1 is a view partially in end elevation and partially in section of a
generator.
Figure 2 is a sectional detail view of a portion of Figure 1 drawn to an
enlarged scale, certain details, however, being modified.
Figure 3 is a radial sectional view of the portion of the machine shewn in
Figure 2.
Figure 4 is an enlarged view of a portion of Figure 2 to shew the detail and
Figure 5 is a plan view of the part shown in Figure 4, the ends, however,
being removed.
Figure 6 is a view similar to Figure 4, but shewing a modification, and
Figure 7 is a detail end view of a field-magnet pole piece of modified construc-
tion.
The armature core, indicated at 2, is built up of foothed laminae secured by
means of dove-tailed projections in the frame 1 in the usual manner. The
lamine are separated into groups by spacing plates 3 which have substantially
the same general form as the lamina but have lateral ribs so that spaces forming
ventilating channels will be provided between adjacent laminæ. The armature
coils which are placed in the slots between the teeth of the laminæ are not shewn
n any of the figures but are constructed and secured in position in any well
known manner.
The field-magnet core is supported on a spider 5 secured to the dynamo shaft 4

page_text: and is built up of over-lapping segmental laminæ 6 each having a body portion
with dove-tailed grooves or recesses in the spider 5, and having two or more
radial projections 61 to form the pole pieces. The shapes of the pole pieces may
be varied, the sides being parallel as shewn or each side being radial so that
the spaces for the coils have parallel sides. The field-magnet core is divided into
a number of groups by means of ribbed spacing plates 7 so that ventilating
channels are formed, in the same manner as the armature core was divided, and
the whole set of plates and lamina are secured together by means of end plates S
and bolts 9 extending through the whole (see Figure 3).
The ventilating channels through the field-magnet core are preferably arranged
in substantially the same planes as the ventilating channels in the armature core,
so that, as the field-magnet is rotated, it will act as a blower to force the air
through the openings in the spider, the channels in its core, the channels in the
armature core, and the openings in the armature frame.
The arrangements for retaining the field-magnet coils 10 in position are best
shewn in Figures 4 and 5. Grooves 11 are formed in the sides of the pole pieces
and metal wedges 121 with edges located in said grooves are pressed in from the
ends of the slots, said wedges having transverse flanges 122 which meet in the
midd'e and are held there by bolts so that the wedges cannot possibly get out
of position or work loose. The wedges are provided with openings 123 so as not
to impede the ventilation, and with lateral flanges 124 which project over the
adjacent edges or tips of the pole pieces. I prefer to make these wedges of some
good conducting metal, such as copper or brass, and with the construction here
shewn, they will not only serve to hold the coil securely in position, but will
constitute closed secondary circuits adjacent to the pole tips, and thus tend to
equalize the magnetic circuits of the machine by destroying the distorting effect
due to armature reaction at the pole tips.
In Figure 6 the wedges are not provided with side ribs to engage the grooves 11
of the pole pieces 61, but the wedges are grooved and pins 1:3 are driven into the
registering grooves, thus securing and locking the wedge against radial movement.
In Figure 7 I have shewn a considerable number of bolts 14 passing through
the pole piece near its outer end, these bolts being employed in this relation in
order to serve a double object, that is, they not only serve to clamp the lamina
of the core securely together between the end plates, but they also serve in con-
junction with the end plates as closed secondaries, and thus co-operate with the
flanged wedges to destroy the injurious effects of armature reaction and thus
equalize the magnetic circuits of the machine.
For
Machines constructed in accordance with my present invention have many
advantages over those of the rotary field type as heretofore constructed.
example, the field-magnet core built up of overlapping plates and bolted together,
as shewn and described, constitutes a laminated fly wheel of great strength and
permanence of structure; the magnetic circuits are substantially confined to the
laminated structure and are therefore uniform and the fluxes are not obstructed
or interfered with by defects or joints in the cast metal spider: the coils are
substantially surrounded on four sides by metal, .e., by the core proper and the
retaining wedges, so that the heat generated in the coils is readily transferred
to the surrounding metal by conduction and is there dissipated by reason of the
ventilating openings and passages. The heat generated in the field-magnet coils
is thus more effectively dissipated than has heretofore been possible, since it is
transferred by conduction at a more rapid rate than is possible by connection
alone. It has been found in practice that by employing the construction shewn
and described, the amount of copper necessary for a given output of energy is
very much less than in machines of prior construction.

page_text: Improvements in Dynamo Electric Machines.
I, BENJAMIN GARVER LAMME, of 230, Stratford Avenue, Pittsburg, in the County
of Allegheny, and State of Pennsylvania, U.S.A. Electrical Engineer, 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:-
-
My invention relates to dynamo electric machines and has for its object to
improve various details of construction thereof. My improvements comprise
means for securing better ventilation than hitherto in machines, the iron cores
of which are built up of lamine and also devices for retaining in position the
coils or bobbins on the field-magnets of such machines. Incidentally I obtain
various advantages as regards lightness and uniformity of action of the machines,
but the main points which I have in view are the two above referred to, the
intention being to secure an especially simple and yet efficient construction.
In the drawing filed with the Provisional Specification.
Figure 1 is a view partially in end elevation and partially in section of a
generator.
Figure 2 is a sectional detail view of a portion of Figure 1 drawn to an
enlarged scale, certain details, however, being modified.
Figure 3 is a radial sectional view of the portion of the machine shewn in
Figure 2.
Figure 4 is an enlarged view of a portion of Figure 2 to shew the detail and
Figure 5 is a plan view of the part shewn in Figure 4, the ends, however,
being removed.
Figure 6 is a view similar to Figure 4, but shewing a modification, and
Figure 7 is a detail end view of a field-magnet pole piece of modified construc-
tion.
The armature core, indicated at 2, is built up of toothed lamina secured by.
means of dove-tailed projections in the frame 1 in the usual manner. The
laminæ are separated into groups by spacing plates 3 which have substantially
the same general form as the lamine but have lateral ribs so that spaces forming
ventilating channels will be provided between adjacent lamine. The armature
coils which are placed in the slots between the teeth of the laminae are not shewn
in any of the figures but are constructed and secured in position in any well
known manner.
The field-magnet core is supported on a spider 5 secured to the dynamo shaft 4
and is built up of over-lapping segmental laminae 6 each having a body portion
with projections 62 engaging in dove-tailed grooves or recesses 51 in the spider 5,
and having two or more radial projections 61 to form the pole pieces (see Fig. 2).
The shapes of the pole pieces may be varied, the sides being parallel as shewn
instead of each side being radial so that the coils may be readily slipped into
position. The field-magnet core is divided into a number of groups by means
of ribbed spacing plates 7 so that ventilating channels are formed, in the same
manner as the armature core was divided, and the whole set of plates and
lamine are secured together by means of end plates 8 and bolts 9 extending
through the whole (see Figure 3).
The ventilating channels through the field-magnet core are preferably arranged
in substantially the same planes as the ventilating channels in the armature core,
so that, as the field-magnet is rotated, it will act as a blower to force the air
through the openings in the spider, the channels in its core, the channels in the
armature core, and the openings in the armature frame.
The arrangements for retaining the field-magnet coils 10 in position are best

page_text: shewn in Figures 4 and 5. Grooves 11 are formed in the sides of the pole pieces
and metal wedges 121 with edges located in said grooves are pressed in from the
ends of the slots, said wedges having transverse flanges 122 which meet in the
middle and are held there by bolts so that the wedges cannot possibly get out
of position or work loose. The wedges are provided with openings 123 so as not
to impede the ventilation, and with lateral flanges 124 which project over the
adjacent edges or tips of the pole piece. I prefer to make these wedges of some
good conducting metal, such as copper or brass, and with the construction here
shewn, they will not only serve to hold the coil securely in position, but will
constitute closed secondary circuits adjacent to the pole tips, and thus tend to
equalize the magnetic circuits of the machine by destroying the distorting effect
due to armature reaction at the pole tips.
In Figure 6 the wedges are not provided with side ribs to engage the grooves 11
of the pole pieces 61, but the wedges are grooved and pins 13 are driven into the
registering grooves, thus securing and locking the wedge against radial movement,
In Figure I have shewn a considerable number of bolts 14 passing through
the pole piece near its outer end, these bolts being employed in this relation in
order to serve a double object, that is, they not only serve to clamp the lamina
of the core securely together between the end plates, but they also serve in con-
junction with the end plates as closed secondaries, and thus co-operate with the
flanged wedges to destroy the injurious effects of armature reaction and thus
equalize the magnetic circuits of the machine.
Machines constructed in accordance with my present invention have many
advantages over those of the rotary field type as heretofore constructed. For
example, the field magnet core built up of overlapping plates and bolted together,
as shewn and described, constitutes a laminated fly wheel of great strength and
permanence of structure; the magnetic circuits are substantially confined to the
laminated structure and are therefore uniform and the fluxes are not obstructed
or interfered with by defects or joints in the cast metal spider; the coils are
substantially surrounded on four sides by metal, i.e., by the core proper and the
retaining wedges, so that the heat generated in the coils is readily transferred
to the surrounding metal by conduction and is there dissipated by reason of the
ventilating openings and passages. The heat generated in the field magnet coils
is thus more effectively dissipated than has heretofore been possible, since it is
transferred by conduction at a more rapid rate than is possible by convection
alone. It has been found in practice that by employing the construction shewn
and described, the amount of copper necessary for a given output of energy is
very much less than in machines of prior construction.
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. For a dynamo electric machine a rotary field-magnet core built up of
lamina and having pole pieces provided with side grooves near their outer ends
for the reception of coil retaining wedges, said wedges being pushed in from both
ends of the coil and clamped by bolts through transverse flanges of the wedges.
2. The modification of the device for preventing radial movement of the
wedges in which pins are fitted in grooves at the sides of the coil slots and
engage in corresponding grooves in the wedges substantially as described.
3. Dynamo electric machines constructed substantially as described with
reference to Figures 1 to 3 of the accompanying drawings.
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester and Birmingham.