U.S. patent number 3,663,910 [Application Number 05/040,016] was granted by the patent office on 1972-05-16 for shunt reactor having improved insulating fluid circulating means.
This patent grant is currently assigned to Allis-Chalmers Manufacturing Company. Invention is credited to Robert L. Grubb.
United States Patent |
3,663,910 |
Grubb |
May 16, 1972 |
SHUNT REACTOR HAVING IMPROVED INSULATING FLUID CIRCULATING
MEANS
Abstract
A shunt reactor immersed in oil within a rectangular casing has
cylindrical coils with vertical axes aligned in a common plane and
a closed rectangular magnetic shield having laminations in vertical
planes surrounding the coils. Annular washers with apertures
therethrough and radial spacers on each surface are disposed
between the ends of the coils and the magnetic shield and form
radial ducts communicating with vertical cooling ducts in the
coils. Barrier means form a closed chamber at the bottom of the
casing and block flow of oil in paths which bypass the coils and
shield and force increased flow of oil into the radial ducts and
through the vertical ducts in the coils, and such barrier means
include angle collars surrounding the lower end of each coil,
baffle members which at one end overlap the angle collars and at
the other end project horizontally outward, and flexible elongated
steel members affixed to the casing sidewalls which extend inwardly
and downwardly of the casing and interfere with and are pushed
outwardly by the horizontal baffle member when the reactor is
lowered into the casing, thereby forming dams preventing upward
movement of oil along the casing sidewalls.
Inventors: |
Grubb; Robert L. (New Berlin,
WI) |
Assignee: |
Allis-Chalmers Manufacturing
Company (Milwaukee, WI)
|
Family
ID: |
21908615 |
Appl.
No.: |
05/040,016 |
Filed: |
May 25, 1970 |
Current U.S.
Class: |
336/57; 336/60;
336/58 |
Current CPC
Class: |
H01F
37/005 (20130101); H01F 27/12 (20130101) |
Current International
Class: |
H01F
27/12 (20060101); H01F 30/06 (20060101); H01F
27/10 (20060101); H01F 30/08 (20060101); H01f
027/08 () |
Field of
Search: |
;336/55,57,58,60,61 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Kozma; Thomas J.
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A shunt reactor having increased flow of insulating fluid
through cooling ducts in the reactor coil comprising, in
combination,
a casing,
insulating fluid within said casing,
a shunt reactor coil and yoke assembly immersed in said fluid
within said casing including a cylindrical coil having a plurality
of vertical cooling ducts extending therethrough between coil
conductor turns so that said insulating fluid circulating through
said cooling ducts is in heat exchange relation with said conductor
turns and also having a vertically extending axial window and
closed laminated magnetic yoke means enclosing said coil and having
upper and lower horizontal laminated magnetic yoke portions having
a width approximately equal to the diameter of said coil disposed
adjacent to and covering both ends of said coil for straightening
the lines of magnetic flux within said coil and said axial window,
said magnetic yoke means having no laminations within said axial
window,
spacer means for forming horizontal radial ducts for said
insulating fluid between the axial ends of said coil and said upper
and lower horizontal yoke portions, said horizontal radial ducts
communicating with said vertical ducts through said coil,
cooling radiator means on a sidewall of said casing communicating
with said insulating fluid and the interior of said casing adjacent
both the upper and lower ends thereof,
pump means for circulating said insulating fluid from the upper
portion of said casing downwardly through said cooling radiator
means and into said lower portion of said casing, and
barrier means for blocking upward flow of said insulating fluid
within said casing between said coil and yoke assembly and the
sidewalls of said casing, whereby said pump means creates a
pressure differential between the upper and lower portions of said
casing and increases the upward flow of said insulating fluid
through said vertical cooling ducts in said coil.
2. A shunt reactor in accordance with claim 1 wherein said barrier
means includes a fluid-blocking member on said coil and yoke
assembly extending horizontally therefrom toward a sidewall of said
casing and an elongated flexible member affixed to a casing
sidewall and extending inwardly and downwardly of said casing to a
position where it interferes with, and is pushed toward said casing
sidewall by, said fluid blocking member when said coil and yoke
assembly is lowered into said casing, thereby forming a dam between
said fluid-blocking member and said flexible member which prevents
upward movement of said insulating fluid along said casing
sidewall.
3. A shunt reactor in accordance with claim 2 wherein said barrier
means also includes an insulating collar surrounding said coil and
having a peripheral flange extending horizontally therefrom and
said fluid-blocking member is a horizontal plate having one edge in
overlapping relation with said peripheral flange on said insulating
collar.
4. A shunt reactor in accordance with claim 3 where said peripheral
horizontal flange is flexible and said fluid-blocking plate is
rigidly held on said coil and yoke assembly and said edge thereof
in overlapping relation to said peripheral horizontal flange
conforms to the outer periphery of said coil.
5. A shunt reactor in accordance with claim 1 wherein said means
for forming horizontal radial ducts includes horizontal flat
annular washers having elongated radial spacers affixed to both
surfaces thereof and a plurality of apertures through said
washer.
6. A shunt reactor in accordance with claim 2 wherein said casing
has vertical side and end walls and said barrier means includes
fluid-blocking members affixed to and extending horizontally from
the sides and ends of said coil and yoke assembly and elongated
flexible members affixed to the interior surface of said casing
sidewalls and end walls of extending inwardly and downwardly
thereof to a position where they interfere with, and are pushed
outwardly by, said fluid-blocking members when said core and yoke
assembly is lowered into said casing.
7. A shunt reactor in accordance with claim 2 having means
including upper side frame members disposed on opposite sides of
said upper yoke portion for clamping said laminations of said upper
yoke portion, means including lower side frame members disposed on
opposite sides of said lower yoke portion for clamping said
laminations of said lower yoke portion, and vertical tie members
connecting said upper and lower side frame members.
8. A shunt reactor in accordance with claim 7 wherein said
fluid-blocking plate is held on said coil and yoke assembly in
vertical spaced relation to one of said lower side frame members to
define a horizontal aperture for said insulating fluid leading to
said vertical ducts and said means for forming horizontal radial
ducts at the lower end of said coil includes a horizontal flat
annular washer having elongated radial spacers affixed thereto
disposed between the lower end of said coil and said lower yoke
portion and approximately in the plane of said horizontal
aperture.
9. A shunt reactor in accordance with claim 8 wherein said coil is
wound from conductive sheet material and said annular washer has a
plurality of apertures therethrough and said radial spacers are
affixed to both the upper and lower surfaces of said washer.
10. A shunt reactor in accordance with claim 2 wherein said
laminated magnetic yoke means have spacers between certain
laminations providing vertical cooling ducts for said insulating
fluid through said yoke means.
11. A coreless iron shunt reactor having means for increasing flow
of insulating fluid through ducts in the reactor coil comprising,
in combination,
a casing,
insulating fluid within the casing,
a shunt reactor coil and yoke assembly immersed in said fluid
within said casing including a cylindrical coil having a plurality
of vertical cooling ducts extending therethrough between coil
conductor turns so that said insulating fluid circulating through
said cooling ducts is in heat exchange relation with said coil
conductor turns and also having a vertical extending axial window
and a closed magnetic yoke having magnetic steel laminations in
vertical planes enclosing said coil and having upper and lower
horizontal yoke portions approximately as wide as the diameter of
said coil disposed above and below the axial ends of said coil
respectively connected by end vertical yoke portions, said magnetic
yoke having no laminations within said axial window,
said coil and yoke assembly also having means including upper
horizontal structural iron side frame members disposed on opposite
sides of said upper yoke portion for clamping said laminations of
said upper yoke portion, means including lower horizontal
structural iron side frame members disposed on opposite sides of
said lower yoke portion for clamping the laminations of said lower
yoke portion, and vertical tie members connecting said upper and
lower side frame members,
cooling radiator means on a sidewall of said casing communicating
with the interior of said casing adjacent the upper and lower ends
thereof,
pump means for circulating said insulating fluid from the upper
portion of said casing downwardly through said cooling radiator
means and into the lower portion of said casing,
spacer means for defining horizontal radial ducts for said
insulating fluid between the ends of said cylindrical coil and said
upper and lower yoke portions and communicating with said vertical
ducts, and
barrier means for blocking upward flow of said insulating fluid
between said coil and yoke assembly and the side and end walls of
said casing and including oil-blocking members extending
horizontally from the sides and ends of said coil and yoke assembly
and elongated flexible members affixed to said casing side and end
walls and extending inwardly and downwardly of said casing to a
position where said flexible members interfere with and are bent
toward said casing walls by said oil-blocking members when said
coil and yoke assembly is lowered into said casing.
12. A shunt reactor in accordance with claim 11 wherein said
barrier means includes an angle collar surrounding said cylindrical
coil and having a flexible horizontally extending flange and at
least one of said oil-blocking members is a horizontal plate having
an edge conforming to the outer periphery of said coil and engaging
said flexible flange on said angle collar in overlapping relation
to form a dam preventing upward movement of said insulating fluid
in paths bypassing said coil.
13. A shunt reactor in accordance with claim 12 wherein said
oil-blocking plate is spaced above one of said lower side members
and forms therewith a horizontally extending aperture for said
insulating fluid approximately in the plane of said radial
ducts.
14. A shunt reactor in accordance with claim 13 wherein said coil
is wound from conductive sheet material and each of said spacer
means for forming horizontal ducts includes an annular insulating
washer having a plurality of elongated insulating radial spacers
affixed to each surface thereof and a plurality of apertures
therethrough communicating with said vertical ducts in said
coil.
15. A shunt reactor in accordance with claim 14 wherein said
magnetic yoke has spacer means between certain of said laminations
providing cooling ducts through said magnetic yoke for said
insulating fluid.
16. A shunt reactor in accordance with claim 2 wherein said coil
and yoke assembly includes a plurality of cylindrical coils with
their axes aligned in a vertical plane and each having a plurality
of vertical cooling ducts therethrough and a vertically extending
axial window and said closed laminated yoke means encloses said
plurality of cylindrical coils with said upper and lower horizontal
yoke portions covering both axial ends of each of said plurality of
cylindrical coils.
Description
This invention relates to temperature modifying means for
stationary induction apparatus and in particular to insulating
fluid circulating means for coreless shunt reactors.
Coreless shunt reactors for reactive compensation may be of the
oil-filled type such as disclosed in U.S. Pat. No. 3,443,119 to E.
T. Norton wherein the shunt reactor is immersed in an insulating
fluid within a casing and the fluid is circulated to dissipate the
losses and prevent the temperature rise from exceeding the thermal
rating of the unit. Coreless iron shunt reactors utilize magnetic
yokes adjacent both axial ends of the reactor coils to straighten
the lines of magnetic flux within the coils for the purpose of
minimizing eddy current heating caused by cross flux and of
increasing the inductance in comparison to an air core reactor of
the same coil dimensions. The laminated magnetic yokes adjacent
both axial ends of the reactor coils obstruct the flow of cooling
liquid in an axial direction through the coils, and U.S. Pat. No.
3,466,582 to William C. Sealey and Michael W. Waterman discloses a
magnetic yoke for a coreless iron reactor having expanded metal
spacers at selected positions between the laminations of the
magnetic yoke which minimize the amount of iron in the yoke and
also provide cooling ducts for the circulation of the liquid
insulating coolant through the yoke and through cooling ducts in
the coils to aid in dissipating heat generated by dielectric losses
in the coil insulation. However, it is often desirable to further
decrease the temperature rise of coreless iron shunt reactors, and
it is an object of the invention to provide a shunt reactor having
improved means for dissipating the losses for the coils and
magnetic yoke and for decreasing the copper-over-oil temperature of
the reactor.
It is a further object of the invention to provide a shunt reactor
having improved means for forcing the insulating fluid through
cooling ducts in the reactor coils to dissipate the losses for the
reactor coils.
Still another object of the invention is to provide a shunt reactor
having improved means for increasing flow of insulating fluid
through the coil ducts using barriers for blocking off oil bypass
paths around the yoke and coil assembly and for creating a pressure
differential between the upper and lower portions of the tank.
A still further object is to provide such a shunt reactor having
oil-blocking means which provide efficient sealing off of the
bypass paths regardless of substantial variation in dimensions of
the casing or of the coil and yoke assembly as a result of
manufacturing tolerances and which blocking means does not
deteriorate when exposed to hot insulating fluid.
These and other objects and advantages of the invention will be
more readily apparent from the following detailed description when
considered in conjunction with the accompanying drawing
wherein:
FIG. 1 is a plan view of a three phase shunt reactor embodying the
invention with the tank cover removed and with parts cut away to
better illustrate the internal construction;
FIG. 2 is an elevation view of the shunt reactor of FIG. 1 with the
front wall of the tank removed;
FIG. 3 is a transverse sectional view through the shunt reactor of
FIGS. 1 and 2;
FIG. 4 is a view taken along line IV-IV of FIG. 1; and
FIG. 5 is an isometric view of a portion of the coil and yoke
assembly of the shunt reactor of FIG. 1.
Referring to the drawing, the preferred embodiment of the invention
is shown incorporated in a three phase shunt reactor having a three
phase coil and yoke assembly 10 immersed in an insulating fluid
such as transformer oil 11 within a casing 12 of rectangular cross
section. The coil and yoke assembly 10 includes three cylindrical
coils A, B and C, one for each of the phases, disposed with their
axes vertical and aligned in a common plane parallel to the
longitudinal axis of rectangular tank 12. Each coil A, B and C
preferably is relatively short in the axial direction and has a
ratio of coil radius to coil axial length greater than 0.25 to
decrease the length of the nonmagnetic flux path and thus increase
the inductance as disclosed in the aforementioned U.S. Pat. No.
3,466,582. Each coil A, B and C has a non-magnetic core which
preferably comprises an axial opening through the coil defined by
an insulating support tube 14 with its axis vertical and upon which
sheet conductor 15 such as aluminum sheet is wound spirally as
disclosed in the copending application of Michael W. Waterman, Ser.
No. 64,472 filed Aug. 17, 1970, having the same assignee as this
invention, with elongated insulating spacers 17 between adjacent
conductor turns extending parallel to the coil axis to provide
vertical ducts 18 for the circulation of insulating fluid 11
through the coil in a direction parallel to the axis.
Alternatively, each coil A, B and C may be of the drum type or
comprise a plurality of axially aligned pancake windings (not
shown) surrounding a support tube 14 and having vertical cooling
ducts therethrough.
A closed magnetic yoke 20 has laminations 21 of magnetic steel in
vertical planes parallel to the axis of the three phase coils A, B
and C disposed adjacent both axial ends of all three phase coils A,
B and C to straighten the lines of magnetic flux within the coils
and to minimize eddy current heating caused by the radial component
of the magnetic flux. The closed magnetic yoke 20 preferably is
similar to that disclosed in aforementioned U.S. Pat. No. 3,443,119
and has an elongated horizontal upper yoke portion 22U adjacent the
upper axial end of all three coils A, B and C and an elongated
horizontal lower yoke portion 22L adjacent the lower axial end of
the three coils A, B and C connected by vertical end yoke portions
24 completing a closed, low reluctance magnetic circuit of high
permeability in surrounding relation to all three coils A, B and C.
The horizontal yoke portions 22U and 22L may comprise yoke
laminations 21Y and the end yoke portions 24 may comprise end
laminations 21E, and the ends of the laminations 21Y and 21E may be
mitered (not shown) and the miter joints between end and yoke
laminations 21Y and 21E may be offset in alternate layers to
provide an overlap joint arrangement (not shown) which decreases
the reluctance of the iron path and increases the mechanical
strength of the yoke 20. Elongated flat fillers, or spacers 26 (see
FIG. 1) of expanded metal construction are provided between
laminations 21Y in the horizontal yoke portions 22 and also between
the end laminations 21E in the end yoke portions 24 to provide
ducts for circulation of the insulating fluid 11 through yoke 20,
and the number of layers of spacers 26 is varied horizontally in a
direction perpendicular to the planes of the laminations so that
the magnetic flux density in the iron path external to the coils A,
B and C is approximately uniform along any horizontal cross section
through the yoke 20. Preferably the cross sectional area of iron
per unit dimension of yoke thickness in a horizontal direction is a
maximum near the center of the yoke opposite the axial opening in
each coil A, B and C where the flux density is a maximum and
decreases progressively from the center toward the outer edges of
the yoke 20 so that the flux density in any horizontal cross
section through the yoke 20 is approximately uniform along the
entire thickness of the yoke 20.
Structural iron, upper side frame members 28U of box cross section
are disposed on opposite sides of upper yoke portion 22U, and
transverse I-beam members 29 disposed above upper yoke portion 22U
are connected at their ends to the upper side frame members 28U to
clamp the yoke laminations 21Y of upper yoke portion 22U. Similarly
structural iron, lower side frame members 28L of box cross section
are disposed on opposite sides of lower yoke portion 22L, and
transverse I-beam feet 32 disposed below lower yoke portion 22L and
resting on the bottom wall 33 of the casing 12 are affixed at their
ends to the lower side frame members 28L and clamp the yoke
laminations 21Y of the lower yoke portion 22L. Vertical structural
iron tie members 35 are welded to the upper side frame members 28U
and the lower side frame members 28L adjacent the ends thereof to
form a rigid unitary assembly 10 of coils A, B and C and yoke 20.
Vertical tie members 35 are shown as being of box cross section but
such members of open channel cross section are equally
suitable.
Upper horizontal I-beam bracing members 37U disposed between the
end yoke portions 24 and the end walls 38 of casing 12 may be
welded to angle support brackets (not shown) affixed to the
vertical tie members 35, and similarly lower horizontal I-beam
bracing members 37L disposed between the end yoke portions 24 and
the casing end walls 38 may be welded to angle support brackets
(not shown) affixed to the vertical tie members 35.
A plurality of cooling radiators 40 (see FIG. 3) affixed to a
sidewall 41 of casing 12 communicate with the interior of casing 12
adjacent the upper and lower margins of sidewall 41, and pump means
42 are provided to circulate the insulating fluid 11 through the
cooling radiators 40, the ducts in magnetic yoke 20 formed by
spacers 26, and through the vertical ducts 18 in the coils A, B and
C.
In accordance with the invention means are provided to force
increased flow of oil 11 through vertical cooling ducts 18 in coils
A, B and C, and such means may include barriers to form a closed
chamber at the bottom of casing 12 which blocks the flow of oil 11
in paths which bypass the coils A, B and C and yoke 20 and which
creates a pressure differential between the upper and lower ends of
the casing 12 to increase the flow of oil through the vertical
ducts 18 in coils A, B and C. Such oil blocking barriers are
partially formed by insulating angle collars 43 surrounding each
cylindrical coil A, B and C a slight distance above the lower end
thereof. Further, a pair of oil-blocking, or baffle plates 44 of
suitable insulating material having opposed semicircular cutout
portions 45 are disposed in a common horizontal plane with the
semicircular portions 45 abutting the outer periphery of each coil
and overlapping the horizontal flange 46 on the corresponding angle
collar 43. The oil-blocking plates 44 extend horizontally outward
beyond the coils A, B and C and abut against elongated flexible
steel members 47 affixed to the interior of the casing sidewalls 41
and together therewith form dams which prevent upward flow of oil
11 along the casing sidewalls 41. The flexible steel members 47 may
be secured adjacent their upper edge to the interior of the casing
sidewalls 41 and bent inwardly and downwardly of the casing 12 so
that they interfere with and are pushed outwardly by the
oil-blocking plates 44, when the coil and yoke unit 10 is lowered
into casing 12, to form the desired dams blocking upward flow of
oil 11 along casing sidewalls 41. The angle collars 43 are of
sufficiently thin material to be flexible, and the horizontal
flange 46 thereof is forced upwardly against the oil-blocking
plates 44 by the greater oil pressure at the bottom of the casing
12 to seal between the oil-blocking plates 44 and the angle collars
43.
A horizontally elongated entrance aperture 49 for flow of oil 11
into the vertical ducts 18 in the coils A, B and C is provided
between each oil-blocking plate 44 and the corresponding box
section lower side frame member 28L, and such oil entrance aperture
49 is in the same horizontal plane as a horizontal lower annular
insulating washer 50L having a plurality of apertures 51 (see FIG.
1) therethrough and also having a plurality of radially extending
insulating spacer members 53 affixed to both the upper and lower
surfaces thereof. Annular washer 50L having radial spacers 53
affixed to both surfaces thereof is disposed between the lower yoke
portion 22L and the bottom edge of the coil turns of sheet
conductor 15 and defines radial oil flow ducts which communicate
with the vertical ducts 18 formed by spacers 17 between adjacent
spiral turns of sheet conductor 15.
Similarly an upper annular horizontal washer 50U having a plurality
of apertures 51 therethrough and radial insulating spacers 53
affixed to both upper and lower surfaces thereof is disposed at the
upper end of each coil A, B and C between the upper edge of the
sheet conductor coil turns 15 and the upper yoke portion 22U and
defines radial ducts for the oil at the upper end of the coils
which communicate with the vertical ducts 18 between adjacent turns
of sheet conductor 15.
The oil-blocking plates 44 are secured by suitable fastening means
(not shown) to a rectangular framework of horizontal longitudinal
wooden members 55 extending longitudinally of casing 12 and wooden
members 56 extending transversely of casing 12 between the coils.
The wooden members 55 and 56 have rabbetted joints at their mating
ends, and the transverse members 56 are secured, in turn, by
fastening means 58 (see FIG. 1) to metallic vertical tie members 59
which are welded to the box section upper and lower side frames 28U
and 28L at positions between the coils.
The lower I-beam braces 37L at each end of the yoke 20 abut against
elongated flexible steel members 61 similar to the flexible members
47 and which are affixed to the inner surface of the end walls 38
of casing 12 to form dams that block upward flow of the oil 11
along the casing end walls 58.
Flat horizontal L-shaped members 63 are positioned at each of the
four inside corners of casing 12 in the same horizontal plane as
the oil-blocking plates 44 and obstruct upward movement of the oil
11 at the inside corners of casing 12. The L-shaped members 63 may
be affixed to angle brackets 64 (see FIG. 4) having one vertical
flange secured to the vertical tie members 35, and one leg of each
L-shaped member 63 extends as far as the lower I-beam braces 37L
along the casing end walls 38 and the other leg of L-shaped member
63 extends as far as the oil-blocking plates 44 along the sidewalls
41 of casing 12 to assure complete blocking of upward movement of
the oil in the paths which would bypass the vertical ducts 18 in
coils A, B and C.
The support tubes 14 for the coils A, B and C have slots 66 cut at
diametrically opposed portions at both the upper and lower end
thereof which receive elongated transverse bracing plates 67 at the
upper and lower ends of the coils A, B and C. The transverse
bracing plates 67 are disposed against the facing horizontal
surfaces of the box section upper and lower side frames 28U and 28L
and have vertically extending portions 68 (see FIG. 3) at their
ends which overlap the upper and lower side frames 28U and 28L and
are secured by suitable fastening means (not shown) to said side
frames to prevent movement of the coils A, B and C relative to the
yoke 20. Circular members 69 of suitable insulating material are
disposed within the support tubes 14 adjacent the upper and lower
ends thereof and affixed by suitable fastening means such as
insulating bolts (not shown) to the transverse bracing plates 67 to
center the coils A, B and C within the window in yoke 20 and to
hold the coils A, B and C in place during shipping and operation.
The circular members 69 distribute the inertia loads over the
circumference of the support tubes 14 and prevent concentration of
the forces at slots 66. Holes are provided in circular members 69
to allow the support tubes 14 to fill with oil 11.
The oil-blocking plates 44 are secured against movement by the
framework of wooden members 55 and 56 that is fastened to the
vertical tie members 59, and it will be appreciated that the
flexible steel strips 47 on the interior of the tank sidewalls 41
and the flexible insulation angle collars 43 are arranged so that
the pressure differential between the upper and lower portions of
casing 12 forces the flexible members 47 and 43 against the rigidly
held oil-blocking plates 44 to force these sealing surfaces
together. Such sealing arrangement is superior to rubber or plastic
type gasket seals because it provides an efficient seal over a wide
range of differences in dimensions between casing 12 and coil and
yoke unit 10 resulting from manufacturing tolerances and also does
not deteriorate when exposed to the hot oil 11.
While only a single embodiment of the invention has been
illustrated and described, it should be understood that I do not
intend to be limited to the single embodiment for many
modifications and variations thereof will be obvious to those
skilled in the art.
* * * * *