Note: Descriptions are shown in the official language in which they were submitted.
~Z9Z730
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BA8E A88FNBLY FOR DYNA~O-FLECTRIC MACHINE
BACRGROUND OF THE INVENTION
FIELD OF THL INV~NTION
The present invention relates generally to
mounts or base assemblies for mounting dynamo-electric
machines firmly on a flat mounting surface.
DF8CRIPTION OF THE RNOWN ART
Base assemblies which conform to an outer
circumferential periphery of a dynamo-electric machine
shell are known from, for example, United States Patent
Nos. 1,361,136 issued December 7, 1920 to Burke and
3,501,660 issued March 17, 1970 to Wrightman et al, and
Japanese Patent Document 59-89542 published May 23, 1984 to
Suzuki. The known assemblies are formed of sheet metal
which is either welded to or press fitted against the
exterior of the machine shell. In an arrangement disclosed
in French Patent No. 7520969 issued January 28, 1977 to
Myson Fans Ltd. two interlocking sheet metal halves form a
V the upper ends of which are bolted to a motor. Opposite
ends of the halves have openings to receive fastening
elements to secure the assembly to a mounting surface.
The above known base assemblies are not,
however, disclosed as being capable of allowing a machine
shaft to
.
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be positioned at a selected one Or two heights over the
mounting surface, so as to comply with difrerent industry
~tandards, ror example, those prescribed by the Natlonal
Electric Manufacturers Association (NEMA) Publication No.
MG1-1978, and those set out by International
Electrotechnical Commission (IEC), Publication No. 72.
Specifically, although the dimensional standards
prescribed by both the above organizations may be quite
close to one another for a given machine of a certain
power rating, it has been required to manuracture
difrerent base assemblies for the machines to conform to
the machine casing or shell peripheries and, importantly,
to support the shells a proper height over the mounting
surrace so that the axis Or a rotor shaft Or the machine
will extend over the mounting surface at the height
prescribed by the standard Or interest.
Another problem arises in that once the known sheet
metal base assemblies are welded to the machine shell, it
becomes difficult, if not impossible, to remove them from
the machine in the event a different kind Or mounting,
e.g., a C-face or D-rlange type end shield is to be
Qubstituted on the machine.
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SUMMARY OF THE INVENTION
An object Or the invention is to overcome the above
and other shortcomings in the prior known machine base
assemblies.
Another ob~ect of the invention is to provide a base
assembly for ~ounting a dynamo-electric machine on a
mounting surface, which can be adapted to support the
machine at a selected height above the mounting surface.
Yet another object Or the invention i9 to provide a
detachable base arrangement in which a cradle portion Or a
base member is welded to the machine shell in a manner
which allows the 4~Y}~h~ to be removed with relative ease
without damage to the ~achine.
According to the invention, a base assembly for a
dynamo-electric machine includes a generally rectangular
integral metallic sheet oomprirod ~r flat foot portions, a
cradle portion lntermediate the root portions, and leg
portions each inclined upwardly from a corresponding foot
portlon toward the axis Or the machine shell and ~oining
with ends Or the cradle portion. The flat foot portions
are capable Or being drawn to increase the height at
which an axial center line Or an arcuate surface on the
cradle portion is supported over the mounting surface.
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Accordingly, the axis Or the machine rotor shaft will
extend at a greater one of two dirrerent heights
prescribed for the rotor axis, by e.g., industry
standards.
According to another aspect Or the invention, a
detachable base arrangement for a dynamo-electric machine
includes a cylindrical shell ror surrounding a machine
stator and having ~irst mountlng holes. A base member
for mounting the machine on a mounting surrace includes
flat root portions, a cradle portion intermediate the foot
portions, and leg portions each inclined ùpwardly from a
corresponding foot portion toward the axis Or the shell
and ~oining with ends of the cradle portion to support the
cradle portion a prescribed height above the mounting
surface. The cradle portion has a set Or mounting holes
,~o ~
or aligning with at least some corresponding mountc~'
holes provided in the machine shell, and the cradle
portion is welded to the 3hell through at least some of
the mounting holes in the cradle portion in a manner to
c~t
allow the welds to be romovod with a milling tool and the
cradle portion to be separated from the shell.
The various features Or novelty which characterize
the invention are pointed out with particularity ln the
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claims annexed to and rormlng a part Or the pre~ent
disclosure. For a better understanding Or the lnventlon,
its operatlng advantages and speclric ob~ects attalned by
its use, reference should be had to the accompanylng
drawing and descriptive matter in which there are
lllu~trated and described prererred embodiments Or the
invention.
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BRIEF DESCRIPTION _ THE DRAWING
F.g. 1 ls an end view, partly in section, Or a base
assembly accordlng to the lnvention, supporting a shell Or
a dynamo-electric machine on a mounting surrace;
Fig. 2 i8 a side view Or an end portion Or the base
assembly and machine in Fig. 1;
Fig. 3 is a plan view Or the base assembly, as seen
from underneath the machine in Fig. 1;
Fig. 4 is a plan view Or a second embodiment ~or the
base assembly as seen loo~ing upward rrom a mounting
surface;
Fig. 5 i~ a side view of the base assembly Or Fig.
4;
Fig. 6 is an end view of the base assembly in Fig.
4 showing a cradle portion supported above a mounting
surface by a rirst preset height; and
Fig. 7 is an end view Or the base assembly in Fig.
4, showing the cradle portion supported at a second preset
height above the mounting surface.
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DESCRIPTION OF THE PREFERRED EMBODMIENT
Fig. 1 shows a base assembly 10 accordlng to the
invention, on which an outer casing or shell 12 Or a
dynamo-electric machine ls mounted. The shell 12 ls
generally cylindrical in cross section, and the machine
includes a rotor shart 14 coaxial with the Qhell 12 and
arranged to extend parallel to and a certain height H
above a mounting surrace 16. The height H may be, ror
example, between 113.54 mm. to 114.30 mm. in the case Or a
type 182/184 FR NEMA Standard, and between 112 mm. to
111.5 mm. ror a type 11 2S/112M FR IEC Standard.
Base aQsembly 10 is formed Or a generally
rectangular integral metallic sheet and lncludes foot
portions 18a, 18b, a cradle portion 20 intermediate the
root portions 18a, lBb, and leg portions 22a, 22b, each
incllned upwardly rrom a corresponding foot portion 18a,
18b, ln a direction toward the axis Or the shell 12, and
~oining into axially extending ends Or the cradle portion
20.
The cradle portion 20 has an arcuate surface 24
which conforms to the portion Or the outer circumference
of the Qhell 12 which seats on the base assembly 10. The
shell 12 has a set of first mounting holes 26a, 26b. The
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foot portions 18a, l~b, of the base assembly 10 have a set
of second mounting holes 28a, 28b for receiving bolt number
30a, 30b which fix the flat foot portions 18a, 18b to the
mounting surface 16. The mounting surface 16 has a bolt
hole configuration, which conforms to one of the industry
standards to which the base assembly 10 can be adapted.
A third set of mounting holes 32a, 3ab are
provided in the cradle portion 20 for alignment with at
least some of the first set of mounting holes 26a, 26b in
the machine shell 12.
Bolts 34a, 34b are received through some of the third set
of mounting holes 32a, 32b to engage threads in the first
set of holes and fix the cradle portion 20 to the shell 12.
Rail cover members 36a, 36b each have one lateral extremity
36c, 36d bolted against a corresponding foot portion 18a,
18b of the base, and
provide means to conceal bolt shafts or shanks 38a, 38b.
These members are anchored at lateral extremities 36e, 36f
by hooking over a corresponding bolt shaft 38a, 38b. The
bolts or shafts 38a, 38b run axially of the machine near
the outer periphery of the shell 12 in the region of each
leg portion 22a, 22b and secure
end frames or covers 40 of the machine against the open
ends of the shell 12 (see Fig. 2).
When the base assembly 10 is
fastened to the mounting surface 16 at the
floor portions 18a, 18b, by the bolt members
30a, 30b, and the machine shell 12 is seated firmly against
the cradle portion 20, the leg portions 22a, 22b maintain
the axial center line of the arcuate
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surface 24 (i.e. the line about which the arcuate surrace
24 is symmetrical) a preset height h above the mounting
surface 16. The preset height h is such that the axis Or
the machine rotor shart 14 will be at the selected height
H parallel to the mounting surrace 16.
According to the invention, the flat foot portions
18a, 18b, are capable Or being drawn to increase the
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preset height h an al~ount- sufricient~so that the axis Or
the rotor shaft 14 will extend a second selected height
over the mounted surIace 16 which second height H iQ
greater than the rirst Qelected height H.
For example, for the 112S~112M FR IEC Standard, a
firQt preset height h can be in the range of from about
6.49 mm. to about 6.95 mm. For the 182/184 FR NEMA
Standard, a second preset height h may be in the range Or
from about 8.6 mm. to about 9.24 mm. The precise value
for the preset height h for a particular standard will
depend on the radius Or curvature Or the arcuate surface
24 and the thickness Or the material forming the integral
metallic sheet Or the base assembly 10.
For the configuration Or base assembly 10, shown in
Figs. 1-3, it is preferred that the integral metallic
sheet be made rrom low carbon steel and have a thickness
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of about 5.00 mm. For the mentioned IEC Standard, the
first preset height h is preferably in the range of from
about 6.49 mm. to about 6.85 mm. For the mentioned NEMA
Standard, leg portions 22a, 22b, should be drawn so that
the second preset height _ is inthe range from about 8.66
mm. to about 9.02 mm.
The second mounting holes 28a, 28b in the flat
foot portions 18a, 18b are oversized, so that they will
match either one of the standard bolt hole configurations.
For the sake of convenience for the ultimate
user,
dynamo-electric machines can be provided with the base
assembly 10 already fixed to the machine shell 12, and the
base assemblies can be removed for substitution of C-face
or D-flange type end shields on the machines with little
resultant damage to the machine shells or casings.
Specifically, as shown in Fig. 3, and according to
the invention, some of the third set of mounting holes 32a,
32b in the cradle portion 20 overlie parts of the shell 12.
The cradle portion 20 is puddle welded to the shell 12
through at least some of the third set of mounting holes
32a, 32b, in a manner to allow the welds to be cut with a
milling tool and the cradle portion 20
to be separated from the shell when the
mentioned substitution is desired. It is preferred that
the cradle portion 20 be welded both to the shell 12 and to
the machine stator encased in the shell through at least
one of the third set
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of mounting holes in the cradle portion 20. As shown in
Fig. 3, the pair of mounting holes 32a, 32b marked S and
located medially of the axial ends of the base assembly 10
are provided in the cradle portion 20 to allow spot or
puddle welding of the cradle portion to the machine shell
and the encased stator core.
A second embodiment of a base assembly 10'
according to the invention is shown in Figs. 4-7. Parts
corresponding to those of the embodiment in Figs. 1-3 are
indicated with similar reference numerals.
The base assembly 10' preferably is formed of
low carbon steel with a thickness of about 3.80 mm. The
first preset height h' then may be in the range of from
about 6.80 mm. to about 6.95 mm. for the mentioned IEC
Standard. An end view of the base assembly 10' when in the
IEC configuration is shown in Fig. 6.
To meet the mentioned NEMA Standard, the foot
portions 18a, 18b are drawn to result in the configuration
shown in Fig. 7. Here, the second preset height h ' is
preferably in the range of from about 8.84 to about 9.24
mm.
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Bolt cover6 37a, 37b, ~hown in Fig6. 1 and 2, are 6ized
to 6nap fit on bolt6 39a, 39b to form a cover over such bolts.
The cover6 are 6ized to tightly fit against the motor structure
in order to prevent objectionable vibration noise during
operation of the dynamo-electric machine. Bolt covers 37a, 37b
may be made of extruded pla6tic or formed sheet metal, 6uch as,
for example, 6heet 6teel as ~hown in Fig. 1. Bolt covers 37a,
37b may not be u6ed in those ca6es where covers over the through
bolts are not desired. Moreover, covers 36a, 36b may be
optionally omitted if desired.
Referring to Fig. 1, angles oC are 37 degrees, 30
minutes for the location of bolt6 38a, 38b and 39a, 39b. Loca-
tion of bolts 38a, 38b at this angle ensures adequate clearance
for mounting bolt6 30a, 30b during insertion of 6uch bolts into
oversized holes 28a, 28b for both IEC and NEMA applications.
~hus, the combination of over6ized holes 2Ba, 28b permit the use
of the 6ame base for a given motor that will 6atisfy both NEMA
and IEC 6tandard bolt hole configurations.
While the foregoing description represent6 preferred
embodiment6 of the pre6ent invention, it will be obvious to
those 6~illed in the art that various changes and difications
may be made, without departing from the true 6pirit and scope of
the present invention.
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RELATIONSHIP TO OTHER APPLICATIONS
This application has been filed on as well as
commonly assigned Canadian Application Serial No. 561,730 -
DYNAMO-ELECTRIC MACHINE LAMINATION CONSTRUCTION in the name
of Thomas W. Neumann, filed March 10, 1988. Canadian
Application Serial No. 561,099 - CLOSED SLOT ROTOR
CONSTRUCTION in the names of Deepakkumar J. Gandhi et al.,
filed March 10, 1988 and Canadian Application Serial No.
561,100 - LIP STRUCTURE FOR A STATOR IN A DYNAMO-ELECTRIC
MACHINE in the names of Deepakkumar J. Gandhi et al., filed
March 10, 1988.
