Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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INDUCTOR ASSEMBLIES AND METHODS
FOR FORMING THE SAME
RELATED APPLICATIONS
100011 The present application claims the benefit of and priority from U.S.
Provisional Patent Application No. 62/988,122, filed March 11, 2020, and is a
continuation
application of and claims priority from U.S. Patent Application No.
16/114,287, filed August
28, 2018, which claims the benefit of and priority from U.S. Provisional
Patent Application
No. 62/557,289, filed September 12, 2017, the disclosures of which are
incorporated herein
by reference.
FIELD
[001] The present invention relates to inductor assemblies and, more
particularly, to
inductor assemblies including inductor coils and methods for making the same.
BACKGROUND
[002] Inductors coils are used in the AC power networks for power factor
correction,
voltage regulation, reduction of di/dt, and protection of downstream
equipment.
SUMMARY
[001] According to embodiments of the invention, an inductor assembly includes
a
coil including a spirally wound metal foil.
[002] In some embodiments, the coil has a longitudinal coil axis and a radial
coil
thickness, the metal foil has a foil width extending substantially parallel to
the coil axis, and
the foil width is greater than the coil thickness.
[003] In some embodiments, the metal foil has a foil thickness in the range of
from
about 0.5 mm to 1 mm.
[004] In some embodiments, the coil includes an electrical insulator layer
spirally co-
wound with the metal foil.
[005] In some embodiments, the electrical insulator layer has a thickness in
the range
of from about 0.05 to 1 mm.
[006] In some embodiments, the ratio of the foil width to the foil thickness
is in the of
from about 170 to 500.
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[007] According to some embodiments, the metal foil and the electrical
insulator layer
are not bonded to one another across their widths.
[008] In some embodiments, the coil has a substantially cylindrical outer
profile.
[009] According to some embodiments, the inductor assembly includes an
electrically
insulating epoxy resin surrounding and engaging the coil.
100101 In some embodiments, the inductor assembly further includes a second
coil
including a second spirally wound metal foil, and the epoxy resin surrounds
and engages the
second coil, and is interposed between the first and second coils
100111 According to some embodiments, the inductor assembly includes an
enclosure
defining an enclosed chamber, wherein the coil is disposed in the chamber.
100121 In some embodiments, the inductor assembly includes at least one
mounting
bracket supporting the enclosure and the coil
100131 According to some embodiments, the inductor assembly includes a
terminal
bus bar electrically connected to the metal foil and including a terminal, and
an electrically
insulating heat shrunk tube surrounding a portion of the terminal bus bar.
100141 In some embodiments, the coil includes a second metal foil spirally co-
wound
with the first metal foil to form a multilayer conductor.
100151 In some embodiments, the coil includes an electrical insulator layer
spirally
co-wound with the first and second metal foils.
100161 According to some embodiments, the first and second metal foils and the
electrical insulator layer are not bonded to one another across their widths.
100171 According to some embodiments, the coil has a coil longitudinal axis,
the coil
has an innermost winding of the metal foil and an outermost winding of the
metal foil, the
inductor assembly includes a first terminal bus bar connected to the innermost
winding and
projecting outwardly from an axial end of the inductor assembly, and the
inductor assembly
includes a second terminal bus bar connected to the outermost winding and
projecting
outwardly from the axial end of the inductor assembly.
100181 According to embodiments of the invention, a multi-unit inductor system
includes first and second inductor assemblies The first inductor assembly
includes a first
coil, the first coil including a spirally wound first metal foil. The second
inductor assembly
includes a second coil, the second coil including a spirally wound second
metal foil. The first
coil is electrically connected to the second coil
100191 In some embodiments, the first coil has a first coil longitudinal axis
and the
second coil has a second coil longitudinal axis. Each of the first and second
inductor
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assemblies includes: a first terminal bus bar connected to the coil thereof
and projecting
outwardly from an axial end of the inductor assembly, and a second terminal
bus bar
connected to the coil thereof and projecting outwardly from the axial end of
the inductor
assembly. The first and second inductor assemblies are positioned side-by-side
and the first
terminal bus bar of the second inductor assembly is electrically connected to
the second
terminal bus bar of the first inductor assembly.
100201 According to embodiments of the invention, a method for forming an
inductor
assembly includes spirally winding a metal foil into the form of a coil.
100211 In some embodiments, the method includes spirally co-winding an
electrical
insulator sheet with the metal foil.
100221 According to some embodiments, the metal foil and the electrical
insulator
sheet are not bonded to one another during the step of co-winding the
electrical insulator
sheet and the metal foil
100231 According to some embodiments, a dual coil inductor assembly includes
an
inner coil assembly and an outer coil assembly. The inner coil assembly
includes an inner
coil and first and second terminals. The inner coil includes an inner metal
foil, and an inner
electrical insulator sheet spirally co-wound with the inner metal foil. The
outer coil assembly
includes an outer coil and third and fourth terminals. The outer coil includes
an outer metal
foil, and an outer electrical insulator sheet spirally co-wound with the outer
metal foil. The
outer coil defines an outer coil air core. The inner coil is disposed within
the outer coil air
core so that the outer coil circumferentially surrounds the inner coil. The
first terminal is
electrically connected to the inner metal foil at a first location, the second
terminal is
electrically connected to the inner metal foil at a second location, and the
first and second
locations are spaced apart along the inner metal foil. The third terminal is
electrically
connected to the outer metal foil at a third location, the fourth terminal is
electrically
connected to the outer metal foil at a fourth location, and the third and
fourth locations are
spaced apart along the outer metal foil.
100241 According to some embodiments, the dual coil inductor assembly
includes: a
first terminal bus bar including the first terminal and secured to an
innermost winding of the
inner metal foil; a second terminal bus bar including the second terminal and
secured to an
outermost winding of the inner metal foil; a third terminal bus bar including
the third terminal
and secured to an innermost winding of the outer metal foil; and a fourth
terminal bus bar
including the fourth terminal and secured to an outermost winding of the outer
metal foil.
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100251 In some embodiments, the dual coil inductor assembly includes a clamp
plate
and a fastener mechanically securing one of the first and second terminal bus
bars in
electrical contact with the inner metal foil.
100261 In some embodiments, the inner metal foil and the inner electrical
insulator
sheet are not bonded to one another across their widths, and the outer metal
foil and the outer
electrical insulator sheet are not bonded to one another across their widths.
100271 According to some embodiments, a method for using a dual coil inductor
assembly includes providing a dual coil inductor assembly including an inner
coil assembly
and an outer coil assembly. The inner coil assembly includes an inner coil and
first and
second terminals. The inner coil includes an inner metal foil, and an inner
electrical insulator
sheet spirally co-wound with the inner metal foil. The outer coil assembly
includes an outer
coil and third and fourth terminals. The outer coil includes an outer metal
foil, and an outer
electrical insulator sheet spirally co-wound with the outer metal foil_ The
outer coil defines
an outer coil air core. The inner coil is disposed within the outer coil air
core so that the outer
coil circumferentially surrounds the inner coil. The first terminal is
electrically connected to
the inner metal foil at a first location, the second terminal is electrically
connected to the
inner metal foil at a second location, and the first and second locations are
spaced apart along
the inner metal foil. The third terminal is electrically connected to the
outer metal foil at a
third location, the fourth terminal is electrically connected to the outer
metal foil at a fourth
location, and the third and fourth locations are spaced apart along the outer
metal foil. The
method includes connecting the dual coil inductor assembly to first and second
lines of an
AC electrical system, including: electrically connecting an input of the first
line to the first
terminal; electrically connecting an output of the first line to the second
terminal; electrically
connecting an input of the second line to the third terminal; and electrically
connecting an
output of the second line to the fourth.
100281 According to some embodiments, the first line is a phase line and the
second
line is a neutral line.
100291 According to some embodiments, the first line is a first phase line and
the
second line is a second phase line.
BRIEF DESCRIPTION OF THE DRAWINGS
100301 FIG. 1 is a top, perspective view of an inductor assembly according to
embodiments of the invention.
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100311 FIG. 2 is a cross-sectional view of the inductor assembly of FIG. 1
taken
along the line 2-2 of FIG. 1.
100321 FIG. 3 is a perspective view of the inductor assembly of FIG. 1 wherein
shells
of the inductor assembly are removed for the purpose of explanation.
100331 FIG. 4 is a perspective view of the inductor assembly of FIG. 1 wherein
the
shells and potting of the inductor assembly are removed for the purpose of
explanation.
100341 FIG. 5 is a perspective view of the inductor assembly of FIG. 1 wherein
the
shells, the potting and coils of the inductor assembly are removed for the
purpose of
explanation.
100351 FIG. 6 is a perspective view of a coil assembly forming a part of the
inductor
assembly of FIG. 1
100361 FIG. 7 is a side view of the coil assembly of FIG. 6
100371 FIG. 8 is an end view of the coil assembly of FIG. 6
100381 FIG. 9 is an enlarged, fragmentary, cross-sectional view of the coil
assembly
of FIG. 6.
100391 FIG. 10 is a fragmentary, perspective view of a conductor foil and an
insulator
sheet forming parts of the coil assembly of FIG. 6, wherein the conductor foil
and the
insulator sheet are shown flattened out for the purpose of explanation.
100401 FIG. 11 is an electrical diagram representing a two-phase AC electrical
power
system including the inductor assembly of FIG. 1.
100411 FIG. 12 is a perspective view of an inductor assembly according to
further
embodiments of the invention.
100421 FIG. 13 is a cross-sectional view of the inductor assembly of FIG. 12
taken
along the line 13-13 of FIG. 12.
100431 FIG. 14 is an electrical diagram representing an electrical power
system
including the inductor assembly of FIG. 12
100441 FIG. 15 is a perspective view of an inductor assembly according to
further
embodiments of the invention.
100451 FIG. 16 is a cross-sectional view of the inductor assembly of FIG. 15
taken
along the line 16-16 of FIG. 15.
100461 FIG. 17 is a perspective view of the inductor assembly of FIG. 15
wherein
shells of the inductor assembly are removed for the purpose of explanation.
100471 FIG. 18 is a perspective view of the inductor assembly of FIG. 15
wherein the
shells, potting and coils of the inductor assembly are removed for the purpose
of explanation.
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100481 FIG. 19 is a perspective view of a coil assembly forming a part of the
inductor
assembly of FIG. 15
100491 FIG. 20 is an exploded, perspective view of the coil assembly of FIG.
19.
100501 FIG. 21 is an enlarged, fragmentary, end view of the coil assembly of
FIG.
19.
100511 FIG. 22 is an enlarged, fragmentary, end view of the coil assembly of
FIG.
19.
100521 FIG. 23 is a side view of the coil assembly of FIG. 19.
100531 FIG. 24 is a perspective view of a multi-unit inductor system including
a
plurality of the inductor assemblies of FIG. 15
100541 FIG. 25 is a schematic diagram a multi-unit inductor system including a
plurality of the inductor assemblies of FIG. 1
100551 FIG. 26 is a schematic diagram of the multi-unit inductor system of
FIG. 5
100561 FIG. 27 is a perspective view of an inductor assembly according to
further
embodiments of the invention.
100571 FIG. 28 is a cross-sectional view of the inductor assembly of FIG. 27
taken
along the line 28-28 of FIG. 27.
100581 FIG. 29 is a perspective view of a multi-unit inductor system including
a
plurality of the inductor assemblies of FIG. 27.
100591 FIG. 30 is a perspective view of a coil assembly according to further
embodiments of the invention.
100601 FIG. 31 is an exploded, perspective view of the coil assembly of FIG.
30.
100611 FIG. 32 is a side view of the coil assembly of FIG. 30.
100621 FIG. 33 is an enlarged, fragmentary, end view of the coil assembly of
FIG.
30.
100631 FIG. 34 is an enlarged, fragmentary, end view of the coil assembly of
FIG.
30.
100641 FIG. 35 is a top, perspective view of a dual coil inductor assembly
according
to further embodiments
100651 FIG. 36 is an opposing top, perspective view of the dual coil inductor
assembly of FIG. 35
100661 FIG. 37 is a cross-sectional view of the dual coil inductor assembly of
FIG.
35 taken along the line 37-37 of FIG. 36.
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100671 FIG. 38 is an exploded, perspective view of a coil assembly forming a
part of
the dual coil inductor assembly of FIG. 35.
100681 FIG. 39 is a perspective view of the coil assembly of FIG. 38.
100691 FIG. 40 is an opposing perspective view of the coil assembly of FIG.
38.
100701 FIG. 41 is an end view of the coil assembly of FIG. 38.
100711 FIGS. 42-44 are enlarged, fragmentary, cross-sectional views of the
coil
assembly of FIG. 38 taken along the line 42-42 of FIG. 40.
100721 FIG. 45 is schematic representing an AC electrical power system
including the
dual coil inductor assembly of FIG. 35.
100731 FIG. 46 is schematic representing a further AC electrical power system
including the dual coil inductor assembly of FIG. 35
100741 FIG. 47 is a fragmentary, side view of two conductor foils and two
electrical
insulator sheets forming parts of the coil assembly of FIG. 38, wherein the
conductor foils
and the electrical insulator sheets are shown flattened out for the purpose of
explanation.
100751 FIG. 48 is a fragmentary, perspective view of the two conductor foils
and the
two electrical insulator sheets forming parts of the coil assembly of FIG. 38,
wherein the
conductor foils and the electrical insulator sheets are shown flattened out
for the purpose of
explanation.
100761 FIG. 49 is a top, perspective view of a dual coil inductor assembly
according
to further embodiments.
100771 FIG. 50 is a cross-sectional view of the dual coil inductor assembly of
FIG.
49 taken along the line 50-50 of FIG. 49.
100781 FIG. 51 is a cross-sectional view of a dual coil inductor assembly
according to
further embodiments
100791 FIG. 52 is an enlarged, fragmentary, end view of an inner coil assembly
forming a part of the dual coil inductor assembly of FIG. 51
100801 FIG. 53 is an enlarged, fragmentary, end view of an outer coil assembly
forming a part of the dual coil inductor assembly of FIG. 51.
100811 FIG. 54 is a fragmentary, perspective view of the dual coil inductor
assembly
of FIG. 51.
DETAILED DESCRIPTION
100821 The present invention now will be described more fully hereinafter with
reference to the accompanying drawings, in which illustrative embodiments of
the invention
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are shown. In the drawings, the relative sizes of regions or features may be
exaggerated for
clarity. This invention may, however, be embodied in many different forms and
should not
be construed as limited to the embodiments set forth herein; rather, these
embodiments are
provided so that this disclosure will be thorough and complete, and will fully
convey the
scope of the invention to those skilled in the art.
100831 It will be understood that, although the terms first, second, etc. may
be used
herein to describe various elements, components, regions, layers and/or
sections, these
elements, components, regions, layers and/or sections should not be limited by
these terms.
These terms are only used to distinguish one element, component, region, layer
or section
from another region, layer or section. Thus, a first element, component,
region, layer or
section discussed below could be termed a second element, component, region,
layer or
section without departing from the teachings of the present invention.
100841 Spatially relative terms, such as "beneath", "below", "lower", "above",
"upper" and the like, may be used herein for ease of description to describe
one element or
feature's relationship to another element(s) or feature(s) as illustrated in
the figures. It will be
understood that the spatially relative terms are intended to encompass
different orientations of
the device in use or operation in addition to the orientation depicted in the
figures. For
example, if the device in the figures is turned over, elements described as
"below- or
"beneath" other elements or features would then be oriented "above" the other
elements or
features. Thus, the exemplary term "below" can encompass both an orientation
of above and
below. The device may be otherwise oriented (rotated 900 or at other
orientations) and the
spatially relative descriptors used herein interpreted accordingly.
100851 As used herein, the singular forms "a", "an" and "the" are intended to
include
the plural forms as well, unless expressly stated otherwise. It will be
further understood that
the terms "includes," "comprises," "including" and/or "comprising," when used
in this
specification, specify the presence of stated features, integers, steps,
operations, elements,
and/or components, but do not preclude the presence or addition of one or more
other
features, integers, steps, operations, elements, components, and/or groups
thereof. It will be
understood that when an element is referred to as being "connected" or
"coupled" to another
element, it can be directly connected or coupled to the other element or
intervening elements
may be present. As used herein, the term "and/or- includes any and all
combinations of one
or more of the associated listed items.
100861 Unless otherwise defined, all terms (including technical and scientific
terms)
used herein have the same meaning as commonly understood by one of ordinary
skill in the
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art to which this invention belongs. It will be further understood that terms,
such as those
defined in commonly used dictionaries, should be interpreted as having a
meaning that is
consistent with their meaning in the context of this specification and the
relevant art and will
not be interpreted in an idealized or overly formal sense unless expressly so
defined herein.
100871 Typical inductance coil designs use a conductor which is insulated
using a
varnish and is turned around a spool. However, such designs typically will not
be able to
withstand significant transient overvoltages between the turns of the coil and
will be large in
size, as the load current requires a significant cross-section of the
conductor. In that case,
there is a significant space lost in between the turns of the conductor, as it
has a round shape.
If an insulation cover were mounted over the coil to ensure that it can
withstand very high
transient overvoltages, then the overall coil assembly would become even
larger in size.
Further, vibration might be an issue as there is minimal contact between the
turns of the coil,
allowing some possible movement
100881 With reference to FIGS. 1-11 a dual coil inductor assembly 100
according to
embodiments of the invention is shown therein. The inductor assembly 100 has a
longitudinal axis L-L.
100891 The inductor assembly 100 includes an enclosure 110, a pair of axially
spaced
apart support bases 120, a support shaft 122, an electrically insulating
fitting 124, a pair of
bushings 126, potting 128, insulation sleeves or tubes 129, a first coil
assembly 131, and a
second coil assembly 151.
100901 The bases 120 and shaft 122 are metal (in some embodiments, aluminum).
The shaft 122 is supported by and affixed to the bases 120 at either end.
100911 The fitting 124 is mounted around the shaft 122. The fitting 124 may be
formed of a plastic or polymeric material such as Polyethersulfone with a
dielectric strength
in the range of from about 30 to 40 kV/mm
100921 The coil assemblies 131, 151 (described in more detail below) are
mounted on
the fitting 124 and the shaft 122. The coil assemblies 131, 151 each include a
pair of terminal
bus bars 140, 142, 160, 162.
100931 The enclosure 110 includes a pair of laterally opposed shells 114 and a
pair of
axially opposed end plates 112 that are fastened together to form the
enclosure 110. The
enclosure 110 defines an internal cavity or chamber 118 within which the
support shaft 122,
the fitting 124, the potting 128, the insulation tubes 129, the first coil
assembly 131, and the
second coil assembly 151 are disposed and contained. Four terminal openings
116 are
defined in the enclosure 110 and communicate with the chamber 118.
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100941 The enclosure components 112, 114 may be formed of any suitable
material.
In some embodiments, the enclosure components 112, 114 are formed of an
electrically
insulating polymeric flame retardant material such as Noryl N190X by SABIC
with a
dielectric strength of about 19 kV/mm.
100951 Each of the four insulation tubes 129 surrounds a length of a
respective
terminal bus bar 140, 142, 160, 162 extending through the chamber 118, through
a terminal
opening 116, and beyond the terminal opening 116 a prescribed distance. The
tubes 129 may
be formed of any suitable material. In some embodiments, the tubes 129 are
formed of an
electrically insulating polymeric material. In some embodiments, the tubes 129
are formed of
an electrically insulating elastomeric material. In some embodiments, the
tubes 129 are
formed of an electrically insulating heat shrinkable polymer (e.g., elastomer)
that has been
heat shrunk about the corresponding terminal bus bar 140, 142, 160, 162
100961 The potting 128 fills the void space within the chamber 118 that is not
occupied by the other components. The potting 128 may formed of any suitable
material.
The potting 128 is electrically insulating. In some embodiments, the potting
128 is formed of
a material having a breakdown voltage of at least 18 kV/mm. In some
embodiments, the
potting 128 is an epoxy resin or a Polyurethane resin.
100971 Each bushing 126 is annular and is sandwiched or interposed between an
end
plate 112 and the adjacent base 120 and mounted on the shaft 122. The bushings
126 may be
formed of any suitable material. In some embodiments, the bushings are formed
of a resilient
polymeric material. In some embodiments, the bushings 126 are formed of an
elastomer and,
in some embodiments, a silicone elastomer or rubber.
100981 The coil assembly 131 includes a multi-layer coil 130, an inner
terminal bus
bar 140, and an outer terminal bus bar 142.
100991 The coil 1130 is an air core coil. The coil 130 has a coil axis A-A and
axially
opposed ends 130A, 130B. The coil 130 includes an electrically conductive
conductor sheet,
strip or foil 132 and an electrically insulative insulator strip or sheet 134.
The foil 132 and
sheet 134 are spirally co-wound or wrapped about the axis A-A to form windings
136. The
windings 136 extend progressively from an innermost winding 136E of the
conductor foil
132 in an inner passage 138 to an outermost winding 136F of the conductor foil
132 on the
outer diameter of the coil 130. Each winding 136 is radially superimposed on,
stacked on, or
wrapped around the preceding winding 136.
1001001 The conductor foil 132 has opposed side edges 132A that are axially
spaced
apart along the coil axis A-A and extend substantially parallel to one
another. The conductor
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foil 132 is spirally wound such that each edge 132A remains substantially in
or proximate a
single lateral plane E-E (FIG. 7) throughout the coil 130 from the winding
136E to the
winding 136F. That is, the conductor foil 132 is maintained in alignment with
itself and is
spirally, not helically, wound.
1001011 According to some embodiments, the coil 130 includes at least 10 turns
or
windings from the winding 136E to the winding 136F and, in some embodiments,
from about
60 to 100 turns. It will be appreciated that in the figures the layers 132,
134 and turns of the
coils 130, 150 are not specifically shown or, in FIG. 8, are only partially
shown. As such, the
depictions of the layers 132, 1134 in the drawings may not be to scale with
regard to the
number of turns, the thicknesses of the layers, or the spacing between layers.
1001021 The conductor foil 132 may be formed of any suitable electrically
conductive
material. In some embodiments, the conductor foil 132 is formed of metal. In
some
embodiments, the conductor foil 132 is formed of copper or aluminum
1001031 The insulator sheet 134 may be formed of any suitable electrically
insulative
material. In some embodiments, the insulator sheet 134 is formed of a
polymeric material.
In some embodiments, the insulator sheet 134 is formed of polyester film. In
some
embodiments, the insulator sheet 134 is formed of a material haying a
breakdown voltage of
at least 4 kV/mm and, in some embodiments, in the range of from about 13 kV/mm
to 20
kV/mm.
1001041 The coil 130 is generally tubular. In some embodiments, the outer
profile of
the coil 130 is substantially cylindrical and is substantially circular in
lateral cross-section.
1001051 The coil 130 has a thickness CT (FIG. 7), a length CL (FIG. 7;
parallel with
the coil axis L-L), and an outer diameter CD (FIG. 8). The thickness CT is the
radial
distance from the innermost conductor winding 136E to the outermost conductor
winding
136F in a lateral plane N-N (FIG. 7) orthogonal to the coil axis A-A.
1001061 According to some embodiments, the coil 130 is generally cylindrical
with a
length CL greater than its outer diameter CD. According to some embodiments,
the ratio
CL/CD is at least 0.2 and, in some embodiments, is in the range of from about
0.3 to 1.5.
1001071 FIGS. 9-10 are fragmentary views of the conductor foil 132 and the
insulator
sheet 134 laid flat (e.g., prior to winding into the coil 130). The conductor
foil 132 has a
thickness MT, a length ML, and a width MW. The insulator sheet 134 has a
thickness IT, a
length IL, and a width
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1001081 According to some embodiments, the conductor foil width MW is greater
than the coil outer diameter CD. In some embodiments, the ratio MW/CD is at
least 0.2 and,
in some embodiments, is in the range of from about 0.4 to 1.5.
1001091 According to some embodiments, the conductor foil width MW is greater
than the coil thickness CT. In some embodiments, the ratio MW/CT is at least
0.5 and, in
some embodiments, is in the range of from about 2 to 3.
1001101 According to some embodiments, the thickness MT is in the range of
from
about 0.1 to 2 mm and, in some embodiments, in the range of from about 0.5 mm
to 1 mm.
According to some embodiments, the length ML is in the range of from about 1 m
to 40 m.
According to some embodiments, the width MW is in the range of from about 0.5
cm to 30
cm.
1001111 According to some embodiments, the thickness IT is in the range of
from
about 0.05 to 1 mm According to some embodiments, the length IL is in the
range of from
about 1 m to 40 m. According to some embodiments, the width 1W is in the range
of from
about 0.5 cm to 30 cm.
1001121 According to some embodiments, the ratio MW//MT is at least 2.5 and,
in
some embodiments, is in the range of from about 170 to 500.
1001131 According to some embodiments, the ratio 1W/IT is at least 2.5 and, in
some
embodiments, is in the range of from about 1000 to 4000.
1001141 According to some embodiments, edge sections 134G of the insulator
sheet
134 extend axially outwardly beyond the adjacent edges of the conductor foil
132 a distance
JO (FIG. 7). In some embodiments, the distance 10 is at least 1 mm and, in
some
embodiments, is in the range of from about 3 mm to 10 mm.
1001151 According to some embodiments, the coil 130 is formed by the following
method. The conductor foil 132 is individually formed as a discrete tape,
strip, sheet or foil.
The insulator sheet 134 is separately individually formed as a discrete tape,
strip, sheet or
foil. The preformed foil 132 and preformed sheet 134 are thereafter mated,
laminated or
layered together and spirally co-wound into the coil configuration to form the
coil 130. In
some embodiments, the layers 132, 134 are co-wound about a cylindrical
mandrel, form or
support. In some embodiments, the layers 132, 134 are co-wound about the
fitting 124.
1001161 In some embodiments, the foil 132 and the sheet 134 are not bonded to
one
another along their lengths prior to winding into the coil. That is, the foil
132 and the sheet
134 are loosely co-wound and are not bonded or laminated to one another until
after
formation of the coil 130. In some embodiments, the foil 132 and the sheet 134
are not
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bonded to one another in the completed coil 130 except by the potting 128 at
the ends of the
coil 130. Thus, in this case, the foil 132 and the sheet 134 are not bonded to
one another
across their widths. In some embodiments, the foil 132 and the sheet 134 are
tightly wound so
that air gaps between the windings of the conductor foil 132 are minimized or
eliminated.
1001171 The terminal bus bars 140, 142 may be formed of any suitable
electrically
conductive material. In some embodiments, the terminal bus bars 140, 142 are
formed of
metal. In some embodiments, the terminal bus bars 140, 142 are formed of
copper or tin-
plated copper.
1001181 The inner terminal bus bar 140 (FIG. 2) includes a contact leg 140A
and a
terminal leg Ti joined by a connector leg 140B. The contact leg 140A is
secured in
mechanical and electrical contact with the innermost winding 136E of the
conductor foil 132
by screws 5, nuts 6, and a clamping member or plate 141 (FIG. 8). The
conductor foil
winding 136E is interposed or sandwiched between the contact leg 140A and the
clamping
plate 141. The screws 5 penetrate through the winding 136E and are secured by
the nuts 6
such that the contact leg 140A and the clamping plate 141 compressively clamp
onto the
winding 136E therebetween. The terminal leg Ti extends out of the enclosure
110 through
an opening 116.
1001191 The outer terminal bus bar 142 (FIG. 2) includes a contact leg 142A
and a
terminal leg T2 joined by a connector leg 142B. The contact leg 142A is
secured in
mechanical and electrical contact with the outermost winding 136F of the
conductor foil 132
by screws 5, nuts 6, and a clamping plate 141 (FIG. 5). The winding 136F is
clamped
between the contact leg 142A and the clamping plate 141 by the screws 5 (which
penetrate
through the winding 136F) and the nuts 6 in the same manner as described above
for the
contact leg 140A, the screws 5, the nuts 6, and the clamping plate 141. The
terminal leg T2
extends out of the enclosure 1110 through an opening 116.
1001201 The coil assembly 151 is constructed in the same manner as the coil
assembly
131 and includes a multi-layer coil 150, an inner terminal bus bar 160, and an
inner terminal
bus bar 162 corresponding to the 130, the inner terminal bus bar 140, and the
outer terminal
bus bar 142. The coil 150 has a coil axis B-B.
1001211 The terminal leg T3 of the inner terminal bus bar 160 is secured in
mechanical and electrical contact with the innermost winding 156E of the
conductor foil of
the coil 150 by screws 5, nuts 6, and a clamping plate 141 in the same manner
as described
above for the contact leg 140A, the screws 5, the nuts 6, and the clamping
plate 141. The
terminal leg T3 extends out of the enclosure 110 through an opening 116.
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1001221 The terminal leg T4 of the outer terminal bus bar 162 is secured in
mechanical and electrical contact with the outermost winding 156F of the
conductor foil of
the coil 150 by screws 5, nuts 6, and a clamping plate 141 in the same manner
as described
above for the contact leg 140A, the screws 5, the nuts 6, and the clamping
plate 141. The
terminal leg T4 extends out of the enclosure 110 through an opening 116.
1001231 Thus, in accordance with some embodiments, the coils 130, 150 use a
metal
foil or conductor that is very thin (e.g., from 0.2mm up to 1.5mm) and very
wide (e.g., from
30mm up to 200mm). Then, this conductor in the form of a foil is wrapped
around a plastic
cylinder (e.g., the fitting 124). In between the turns of the foil, a thin
insulating sheet is used
that will provide adequate insulation between the turns of the coil (e.g.,
from 5kV up to
20kV). Bus bars are connected to the inner and outer windings of the conductor
foil and
project out from the enclosure. The bus bars are further electrically
insulated using heat
shrinkable electrically insulating sleeves The heat shrinkable sleeves can
prevent flashover
between the bus bars and the remainder of the coils. The coils are covered
inside a plastic
enclosure and then potted with epoxy resin to provide electrical insulation in
between the
turns of the conductor foil at the two axial ends of the coil. Further, the
potting prevents
humidity from penetrating inside the coil that might reduce the insulation of
the coil or age
the insulation properties of the insulation used. Further, the potting will
also make the coil
more stable in case of vibration and also increase the insulation between the
two outputs of
the coil.
1001241 According to method embodiments, the inductor assembly 100 is a two
phase
coil used in a two phase AC electrical power system 7 as illustrated by the
diagram in FIG.
11. The input of line Li is connected to the terminal T2 and the output of
line Li is
connected to the terminal Ti. The input of line L2 is connected to the
terminal T3 and the
output of line L2 is connected to the terminal T4. In some embodiments, AC
power system
has a voltage Ll-L2 of about 650Vrms and a load current of about 100A. Circuit
breakers
may be provided between the input terminals T2, T3 of the inductor assembly
100 and the
power supply. The output terminals Ti, T4 of the inductor assemblies 100 may
be connected
to a power distribution panel.
1001251 In the event of a surge current (high di/dt) in a line, the insulation
tube 129
will isolate the covered terminal bus bar and thereby prevent flashover
between the coil
connected to that line and a terminal bus bar of the other coil. For example,
it can be seen in
FIG. 3 that the connecting leg 140B of the bus bar 140 extends along the
length of the coil
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150. When a surge current is applied to the coil 150, the tube 129 on the
terminal bus bar 140
can prevent flashover from the coil 150 to the connecting leg 140B of the bus
bar 140.
1001261 The potting 128 (e.g., epoxy resin) covers the ends of the coils 130,
150 and
thereby stabilizes the coils 130, 150 and increases the electrical insulation
between the turns
of the conductor foil (e.g., the conductor foil 132) within each coil 130,
150. The potting 128
also increases the electrical insulation between the adjacent ends of the two
coils 130, 150.
The potting 128 further increases the electrical insulation between the coils
130, 150 and the
bus bars 140, 142, 160, 162.
1001271 The external plastic enclosure 110 can take vibrations and provide
environmental protection for the coils 130, 150. The enclosure 110 also
increases electrical
insulation for the coils 130, 150. The strong mounting brackets or bases 120
and support
shaft 122 can ensure that the inductor assembly 100 can withstand vibration.
1001281 The bushings 126 can serve to take up manufacturing tolerances in the
inductor assembly 100, thereby reducing vibration. The bushings 126 can also
serve to damp
or absorb forces (e.g., vibration) applied to the inductor assembly 100. The
bushings 126 can
also resiliently and temporarily take up expansion of the inductor assembly
100 caused by
heating of the coils 130, 150.
1001291 The potting can also take up manufacturing tolerances in the inductor
assembly 100, thereby reducing vibration.
1001301 Because screws 5 or other fasteners and clamping plates 141 are used
to
secure the bus bars 140, 142, 160, 162 to the innermost and outermost windings
136E, 136F,
156E, 156F, it is not necessary to use a welding or soldering technique that
may melt the thin
coil conductor foil.
1001311 FIGS. 12-14 show an inductor assembly 200 according to further
embodiments of the invention. The inductor assembly 200 is constructed
similarly to the
inductor assembly 100 but includes only a single coil assembly 231. The coil
assembly 231
includes a coil 230 and terminal bus bars 240, 242 corresponding to and
constructed in same
manner as described for the coil assembly 131, the coil 130 and the terminal
bus bars 140,
142. The terminal bus bars 240, 242 have terminal legs T1 and T2 corresponding
to the
terminal legs Ti and T2 of the inductor assembly 100.
1001321 As schematically illustrated in FIG. 14, the inductor assembly 200 can
be
connected in series to the protective earth (PE) of a power system 9 with a
voltage of
650Vrms between its lines and a load current of 100A. The inductor assembly
200 may be
rated for half of the actual line currents (i.e., around 50A) according to
relevant standards.
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The output Ti of the inductor assembly 200 is connected to the PE terminals
inside a
distribution panel.
1001331 According to some embodiments of the invention, an inductor assembly
as
described herein has a specific load current rating of around 100A, can
operate in a normal
low voltage (LV) application (up to 1000Vac), is able to sustain very high
transient
overvoltage events that might be developed across its ends (in the range of
100kV), is able to
comply with extreme vibrating conditions, is able to be installed in outside
environments,
substantially reduces or minimizes the risk of fire under failure, has a small
footprint and size
(e.g., less than 43000 cm3), and is relatively lightweight (e.g., less than 25
kg).
1001341 FIGS. 15-24 show a dual coil inductor assembly 300 according to
further
embodiments of the invention. The inductor assembly 300 is constructed
similarly to the
inductor assembly 100 but is configured such that the terminal legs Ti, T2
extend from one
axial end 302A of the inductor assembly 300, and the terminal legs T3, T4
extend from the
opposite axial end 302B of the inductor assembly 300.
1001351 The inductor assembly 300 includes an enclosure assembly 310, a pair
of
axially spaced apart support bases 320, a support shaft 322, an electrically
insulating fitting
324, a pair of bushings 326, potting 328, insulation sleeves or tubes 329, a
first coil assembly
331, and a second coil assembly 351 corresponding to the components 110, 120,
122, 124,
126, 128, 129, 131, and 151, respectively, except as shown and discussed.
1001361 The enclosure assembly 310 includes a pair of axially opposed,
cylindrical,
cup shaped shells 314 and a pair of axially opposed end plates 312A and 312B.
Each shell
314 defines a chamber 318 to contain a respective one of the assemblies 331,
351 and potting
328. Two terminal openings 316 are defined in each end plate 312 and
communicate with the
adjacent chamber 318. An electrically insulating partition bushing 315 is
interposed between
the adjacent inner ends of the shells 314. The partition bushing 315 may be
formed of a
material as described above for the bushings 126.
1001371 The coil assemblies 331, 351 are constructed in the same manner as the
coil
assemblies 131, 151 except in the configuration of their terminal bus bars
340, 342, 360, 362.
With reference to FIG. 21, the terminal bus bar 340 is connected to the
innermost winding
336E of the coil 330 and has a terminal leg Ti extending through an opening
316 in the end
plate 312A. With reference to FIG. 22, the terminal bus bar 342 is connected
to the
outermost winding 336F of the coil 330 and has a terminal leg T2 extending
through the
other opening 316 in the end plate 312A. The terminal bus bar 360 is connected
to the
innermost winding of the coil 350 and has a terminal leg T3 extending through
an opening
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316 in the end plate 312B. The terminal bus bar 362 is connected to the
outermost winding
of the coil 350 and has a terminal leg T4 extending through the other opening
316 in the end
plate 312B. Each terminal leg Ti, T2, T3, T4 is covered by an insulation tube
329 that
extends through the respective opening 316. Each terminal leg Ti, T2, T3, T4
may further
be covered by an inner insulation tube 327 within the insulation tube 329. The
insulation
tube 327 may be formed of the same material as described for the insulation
tube 129.
1001381 FIGS. 19-23 show the coil assembly 331 in more detail. The coil
assembly
351 is constructed in the same manner as the coil assembly 331. As can be seen
in FIGS. 19-
23, the coil 330 includes a foil 332, an insulator sheet 334, clamp plates
341, and fasteners 5,
6 corresponding to and assembled in the same manner as the components 132,
134, 141, 5
and 6, respectively, of the coil assembly 131. The end of the innermost
winding 336E of the
foil 332 is mechanically secured in electrical contact with the terminal bus
bar 340 by a
clamp plate 341A and fasteners 5, 6 The bus bar 340, clamp plate 341A and
winding 336E
may be received in a slot in the fitting 324 as illustrated. The end of the
outermost winding
336F of the foil 332 is mechanically secured in electrical contact with the
terminal bus bar
342 by a clamp plate 341 and fasteners 5, 6.
1001391 As will be appreciated from FIG. 16, the dual coil inductor assembly
300 has
a longitudinal axis L-L, the coil 330 has a coil axis A-A, and the coil 350
has a coil axis B-B.
The coil axes A-A, B-B are substantially parallel with and, in some
embodiments,
substantially coaxial with, the axis L-L. In some embodiments, the coil axes A-
A, B-B are
substantially parallel with one another. The terminal legs Ti, T2, T3, T4 each
extend or
project axially from an end 302A, 302B of the inductor assembly 300 in a
direction along the
axis L-L. In some embodiments, the terminal legs Ti, T2, T3, T4 each extend
along an axis
that is substantially parallel with the axis L-L.
1001401 Thus, the input terminal Ti.and the output terminal T2 of the coil 330
extend
from the same end 302A of the unit 300. The input terminal T3 and the output
terminal T4
of the coil 350 extend from the same opposing end 302B of the unit 300. This
construction
can enable the coils 330, 350 to be better insulated from one another because
there is no
terminal bus bar from one coil 330, 350 extending across the other coil 330,
350.
1001411 The terminal configuration of the inductor assembly 300 also permits
the
assembly of a multi-unit inductor system 301 as shown in FIGS. 24 and 26, for
example.
The system 301 includes a plurality (as shown, four) of dual coil inductor
assemblies 300A-D
(each constructed as described for the assembly 300) in a relatively compact
side-by-side
arrangement. The inductor coils 330 of the inductor assemblies 300A-D are
connected to the
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line Li and to one another in series by connecting conductors 7 (e.g., metal
cables). The
inductor coils 350 of the inductor assemblies 300A-D are connected to the line
L2 and to one
another in series by connecting conductors 7 (e.g., metal cables).
1001421 In the system 301, the longitudinal axes L-L of the inductor
assemblies
300A-D extend non-coaxially to one another. That is, the respective
longitudinal axes L-L of
the inductor assemblies 300A-D extend (as shown) substantially parallel to one
another but
laterally displaced from one other, or may extend transversely to one another.
1001431 The configuration of the system 301 avoids a coaxial configuration of
inductor assemblies 100A-D as shown in the inductor system 101 of FIG. 25, for
example,
wherein a common central metal post 122' supports each of the coils 130, 150
of the multiple
inductor assemblies 100A-D. In the system 101, the dielectric withstand
voltage of the
system 101 may be limited by the distance D1 between each terminal Ti, T2, T3,
T4 and the
adjacent base 120 In the event of a lightning strike or other surge event, the
induced voltage
on the coil terminals due to the high di/dt will result into a flashover; as a
result the current
may flash over from a terminal Ti- T4 to the adjacent base 120, and from the
base 120 the
current can conduct through the central metal post 122' to the high voltage HV
side of the
circuit, thereby short circuiting around the coils 130, 150 of the downstream
inductor
assemblies 100A-D. That is, the overall dielectric withstand voltage of the
system 101 is
reduced because the voltage potential between the ends LV, HV of the circuit
are bridged by
the central metal post 122'.
1001441 By contrast and with reference to FIG. 26, in the system 301, current
from a
lightning surge or other surge event may still flash over, due to induced
lightning impulse
voltage from the high di/di, from a terminal Ti, T2, T3, T4 to the adjacent
base 320 across a
distance D2. However, in order for the current to conduct to the next inductor
assembly
300B-D, the current must flash over a distance D3 from the base 320 of the
first inductor
assembly 300A to the base 320 of the inductor assembly 300B. The distances
between the
bases 320 of the adjacent inductor assemblies 300A-D can be chosen to provide
an increased
and sufficient dielectric withstand voltage between the inductor assemblies
300A-D and for
the system 301 overall. In this way, a high amount of electrical insulation
between the
inductor assemblies 300A-D is achieved. As a result, the overall lightning
impulse
overvoltage of the overall system 301 from the LV side to the HV side is
maintained. For
example, if the Lightning Impulse breakdown voltage of each inductor assembly
300A-D is
100 kV, then the overall Lightning Impulse breakdown voltage of the system 301
will be 400
kV. This can be accomplished while retaining an electrically conductive metal
support shaft
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322 in each inductor assembly 300A-D. A metal support shaft 322 may be
desirable to
provide improved strength, thermal conductive, resistance to thermal damage
(e.g., melting),
and ease and flexibility in fabrication.
1001451 The partition bushing 315 can electrically insulate the coil
assemblies 331,
351 from one another. The partition bushing 315 can serve to take up
manufacturing
tolerances in the inductor assembly 300, thereby reducing vibration. The
partition bushing
315 can also serve to damp or absorb forces (e.g., vibration) applied to the
inductor assembly
300. The partition bushing 315 can also resiliently and temporarily take up
expansion of the
inductor assembly 300 caused by heating of the coils 330, 350.
1001461 FIGS. 27-29 show an inductor assembly 400 according to further
embodiments of the invention. The inductor assembly 400 is constructed
similarly to the
inductor assembly 300 but includes only a single coil assembly 431. The coil
assembly 431
includes a coil 430 and terminal bus bars 440, 442 corresponding to and
constructed in same
manner as described for the coil assembly 131, the coil 130 and the terminal
bus bars 140,
142. The terminal bus bars 440, 442 have terminal legs Ti and T2 corresponding
to the
terminal legs Ti and T2 of the inductor assembly 300.
1001471 The inductor assembly 400 has a longitudinal axis L-L and the coil 430
has a
coil axis A-A. The coil axis A-A is substantially parallel with and, in some
embodiments,
substantially coaxial with, the axis L-L. The terminal legs Ti, T2 each extend
or project
axially from the end 410A of the inductor assembly 400 in a direction along
the axis L-L. In
some embodiments, the terminal legs Ti, T2 each extend along an axis that is
substantially
parallel with the axis L-L. Thus, the input terminal Ti and the output
terminal T2 of the coil
430 extend from the same end 402B of the unit 400 as discussed above with
regard to the
inductor assembly 300.
1001481 A plurality of the inductor assemblies 300 can be assembled into a
multi-unit
inductor system 401 as shown in FIG. 29, for example. The system 401 includes
a plurality
(as shown, four) of inductor assemblies 400A-D (each constructed as described
for the
assembly 400) in a relatively compact side-by-side arrangement. The inductor
coils 430 of
the inductor assemblies 400A-D are connected to the line Ll and to one another
in series by
connecting conductors 7 (e.g., metal cables).
1001491 In the system 401, the longitudinal axes L-L of the inductor
assemblies
400A-D extend non-coaxially to one another. That is, the respective
longitudinal axes L-L of
the inductor assemblies 400A-D extend (as shown) substantially parallel to one
another but
laterally displaced from one other, or may extend transversely to one another.
This
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configuration can thus provide the advantages discussed above with regard to
the inductor
assembly 300.
1001501 With reference to FIGS. 31-34, a coil assembly 531 according to
further
embodiments is shown therein. The coil assembly 531 can be used in place of
any of the coil
assemblies 131, 151, 231, 331, 351, 431. The coil assembly 531 is constructed
and operates
in the same manner as the coil assembly 331, except at follows.
1001511 The coil assembly 331 includes a coil 530 that differs from the coil
330 as
discussed below. The coil assembly 531 also includes terminal busbars 540,
542, clamp
plates 341, and fasteners 5, 6 corresponding to and assembled in the same
manner as the
components, 340, 342, 341, 5 and 6, respectively, of the coil assembly 331.
1001521 The coil 530 includes a first foil 532 and an insulator sheet 534
corresponding to the foil 332 and the insulator sheet 334. The coil 530
further includes a
second conductor or foil 533 The first and second foils 532, 533 collectively
form a
multilayer electrical conductor 537. The foils 532, 533 may be formed of the
same materials
and in the same dimensions as described above for the foil 132.
1001531 The first foil 532, the second foil 533 and the insulator sheet 534
are spirally
co-wound or wrapped about the coil axis A-A to form windings 536 with the
second foil 533
interposed or sandwiched between the first foil 532 and insulator sheet 534.
The windings
536 extend progressively from an innermost winding 536E of the multilayer
conductor 537
(i.e., the conductor foils 532, 533) to an outermost winding 536F of the
multilayer conductor
537 (i.e., the conductor foils 532, 533) on the outer diameter of the coil
530. Each winding
536 is radially superimposed on, stacked on, or wrapped around the preceding
winding 536.
The foils 532, 533 may be wound tightly in fact to face electrical contact
with one another.
1001541 Each of the conductor foils 532, 533 has opposed side edges that are
axially
spaced apart along the coil axis A-A and extend substantially parallel to one
another. The
conductor foils 532, 533 are spirally wound such that each side edge remains
substantially in
or proximate a single lateral plane (i.e., corresponding to planes E-E of FIG.
7) throughout
the coil 530 from the winding 536E to the winding 536F. That is, the
multilayer conductor
537 and the conductor foils 532, 533 are maintained in alignment with
themselves and are
spirally, not helically, wound. In some embodiments, the conductor foils 532,
533 are
substantially coextensive.
1001551 The end of the innermost winding 536E of the multilayer conductor
(i.e., the
ends of the foil 532 and the foil 533) is mechanically secured in electrical
contact with the
terminal bus bar 540 by the clamp plate 541A and fasteners 5, 6. The bus bar
540, clamp
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plate 541A and winding 536E may be received in a slot in the fitting 524 as
illustrated. The
end of the outermost winding 536F of the multilayer conductor (i.e., the ends
of the foil 532
and the foil 533) is mechanically secured in electrical contact with the
terminal bus bar 542
by the clamp plate 541 and fasteners 5, 6.
1001561 The multilayer conductor 537 has an increased cross-sectional area as
compared to the foil 132 and thereby provides less electrical resistance for a
conductor of the
same length. As a result, the coil 530 (and thereby an inductor assembly
incorporating the
coil assembly 531) can be rated for a greater amperage and power.
1001571 For example, the two-phase inductor assembly 300 may be rated for 100A
for
each line Li, L2 (with the load currents through Li and L2). The PE inductor
assembly 400
may be rated for 50A (i.e., half the rating of the line inductor). In that
case, the coils of the
inductor assemblies 300, 400 each use a single conductor foil.
1001581 The parallel, superimposed conductor foils 532, 533 of the multilayer
conductor 537 double the cross-sectional area of the coil conductor as
compared to the single
foil conductors of the inductor assemblies 300, 400. As a result, the two-
phase inductor
assembly incorporating the coil assembly 531 may be rated for 150A for each
line Li, L2,
and the PE inductor assembly incorporating the coil assembly 531 may be rated
for 75A.
1001591 In some embodiments, the foil 532, the foil 533, and the insulator
sheet 534
are not bonded to one another along their lengths prior to winding into the
coil. That is, the
foils 532, 533 and the sheet 534 are loosely co-wound and are not bonded or
laminated to one
another until after formation of the coil 530. In some embodiments, the foils
532, 533 and
the insulator sheet 534 are not bonded to one another in the completed coil
130 except by the
potting 528 at the ends of the coil 530. In this case, the layers, 532, 533,
534 are not bonded
to one another across their widths. In some embodiments, the foils 532, 533
and the sheet
534 are tightly wound so that air gaps between the windings of the conductor
foils 532, 533
are minimized or eliminated.
1001601 The multilayer conductor 537 provides advantages over using a thicker
single
foil for the coil conductor (e.g., two 0.8 mm foils 522, 533 instead of a
single 1.6 mm foil
132) because a thicker single foil may be too thick to make the turns
efficiently (Le., without
creating gaps in between the turns of the coil, etc.). The outer diameter of
the coil 530 may
be modestly increased as compared to the diameter of the coil 130 while
maintaining the
same coil length. On the other hand, if the conductor cross-section was
increased by using
the same thickness foil 132 (e.g., 0.8 mm) but doubling the width of the foil
132, then the coil
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footprint would be substantially double in length, which may require the
inductor assembly to
have an undesirable footprint.
1001611 With reference to FIGS. 35-48 show a combined dual coil inductor
assembly
600 according to embodiments of the invention is shown therein. The inductor
assembly 600
is constructed similarly to the inductor assemblies 100 and 300 but is
configured such that
two independent coils 630 and 650 are cowound and integrated into a single
coil assembly
631.
1001621 With reference to FIGS. 35-37, the inductor assembly 600 includes an
enclosure assembly 610, a pair of axially spaced apart support bases 620, a
support shaft 622,
an electrically insulating fitting 624, a pair of bushings 626, potting 628,
and insulation
sleeves or tubes 629 corresponding to the components 110, 120, 122, 124, 126,
128, and 129,
respectively, except as shown and discussed. The inductor assembly 600
includes terminal
legs T1, T2 extending from one axial end 602A of the inductor assembly 600,
and terminal
legs T3, T4 extending from the opposite axial end 602B of the inductor
assembly 600. The
dual coil assembly 631 is housed in the enclosure assembly 610 as described
above.
1001631 With reference to FIGS. 38-41, the coil assembly 631 includes a first
coil
630 and a second coil 650 that are combined to form a combined coil 639 as
discussed below.
The coil assembly 631 also includes terminal bus bars 640, 642, 660, 662,
clamp plates 641,
and fasteners 5, 6 (FIGS. 42-44) corresponding to the components, 340, 342,
360, 362, 341,
and 6, respectively, of the coil assembly 331.
1001641 The combined coil 639 includes a first foil 632, a second foil 652, a
first
insulator sheet 634, and a second insulator sheet 654. When spirally wound as
discussed
below and as shown, the first foil 632 forms the first coil 630. When spirally
wound as
discussed below and as shown, the second foil 652 forms the second coil 650.
1001651 The foils 632, 652 may be constructed and formed in the same manner as
described for the foil 132. The foil 632 has an inner end 632A (FIGS. 38 and
42) and an
opposing outer end 632B (FIGS. 38 and 43). The foil 652 has an inner end 652A
(FIGS. 38
and 42) and an opposing outer end 652B (FIGS. 40 and 44). The insulator sheets
634, 654
may be constructed and formed in the same manner as described for the
insulator sheet 134.
1001661 The first foil 632, the second foil 652, the first insulator sheet
634, and the
second insulator sheet 654 are spirally co-wound or wrapped about the coil
axis A-A to form
windings 636 with the insulator sheets 634, 654 interposed or sandwiched
between the first
foil 632 and the second foil 652. The windings 636 extend successively or
progressively
from an innermost winding 636E of the foils 632, 652 to an outermost winding
636F of the
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foils 632, 652 on the outer diameter of the combined coil 639. Each winding
636 is radially
superimposed on, stacked on, or wrapped around the preceding winding 636. The
foils 632,
652 and the insulator sheets 634, 654 may be wound tightly in face-to-face
contact with one
another. That is, each insulator sheet 634, 654 is in face-to-face contact
with the metal foils
632, 652 on either side of said insulator sheet 634, 654, but the metal foils
632, 652 are not in
face-to-face contact with one another. The foils 632, 652 are not in
electrical contact with
one another, but are electromagnetically coupled, as discussed herein.
1001671 FIG. 47 is a fragmentary, side view of the conductor foils 632, 652
and the
insulator sheets 634, 654 shown flattened out prior to winding to form the
combined coil 639.
FIG. 48 is an exploded, fragmentary, perspective view of the conductor foils
632, 652 and
the insulator sheets 634, 654 shown flattened out prior to winding to form the
combined coil
639
1001681 As shown in FIGS. 42-44, 47 and 48, the foils 632, 652 and the
insulator
sheets 634, 654 are interleaved such that the foils 632, 652 are electrically
insulated from one
another by the insulator sheets 634, 654 along the entire length of each foil
632, 652.
1001691 Each of the conductor foils 632, 652 has opposed side edges that are
axially
spaced apart along the coil axis A-A and extend substantially parallel to one
another. The
conductor foils 632, 652 are spirally wound such that each side edge remains
substantially in
or proximate a single lateral plane (i.e., corresponding to planes E-E of FIG.
7) throughout
the coil 639 from the winding 636E to the winding 636F. That is, the conductor
foils 632,
652 are maintained in alignment with themselves and are spirally, not
helically, wound. In
some embodiments, the conductor foils 632, 652 each extend fully from the
outer surface of
the innermost winding 636E to the outermost winding 636F.
1001701 In some embodiments, the foils 632, 652 and the insulator sheets 634,
654 are
not bonded to one another along their lengths prior to winding into the coil.
That is, the foils
632, 652 and the insulator sheets 634, 654 are loosely co-wound and are not
bonded or
laminated to one another until after formation of the combined coil 639. In
some
embodiments, the foils 632, 652 and the insulator sheets 634, 654 are not
bonded to one
another in the completed combined coil 639 except by the potting 628 at the
ends of the
combined coil 639. In this case, the layers, 632, 652, 634, 654 are not bonded
to one another
across their widths. In some embodiments, the foils 632, 652 and the insulator
sheets 634,
654 are tightly wound so that air gaps between the windings of the conductor
foils 632, 652
and the insulator sheets 634, 654 are minimized or eliminated, while enhancing
the
electromagnetic coupling.
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1001711 As shown in FIGS. 37 and 42, the terminal leg Ti is electrically
connected to
the conductor foil 632 at a first location. In some embodiments and as shown,
the first
location is proximate (i.e., at or near) the inner end 632A of the foil 632.
More particularly,
the end of the innermost winding 636E of the conductor foil 632 is
mechanically secured in
electrical contact with the terminal bus bar 640 by a clamp plate 641 and
fasteners 5, 6. The
bus bar 640, clamp plate 641 and conductor foil 632 may be received in a slot
in the fitting
624 as illustrated.
1001721 As shown in FIGS. 37 and 43, the terminal leg T2 is electrically
connected to
the conductor foil 632 at a second location spaced apart from the first
location along the
length of the foil 632. In some embodiments and as shown, the second location
is proximate
(i.e., at or near) the outer end 632B of the foil 632. More particularly, the
end of the
outermost winding 636F of the foil 632 is mechanically secured in electrical
contact with the
terminal bus bar 642 by a clamp plate 641 and fasteners 5, 6
1001731 As shown in FIGS. 37 and 42, the terminal leg T3 is electrically
connected to
the conductor foil 652 at a first location. In some embodiments and as shown,
the first
location is proximate (i.e., at or near) the inner end 652A of the foil 652.
More particularly,
the end of the innermost winding 636E of the conductor foil 652 is
mechanically secured in
electrical contact with the terminal bus bar 660 by a clamp plate 641 and
fasteners 5, 6. The
bus bar 660, clamp plate 641 and conductor foil 652 may be received in a slot
in the fitting
624 as illustrated.
1001741 As shown in FIGS. 37 and 44, the terminal leg T4 is electrically
connected to
the conductor foil 652 at a second location spaced apart from the first
location along the
length of the foil 652. In some embodiments and as shown, the second location
is proximate
(i.e., at or near) the outer end 652B of the foil 652. More particularly, the
end of the
outermost winding 636F of the foil 652 is mechanically secured in electrical
contact with the
terminal bus bar 662 by a clamp plate 641 and fasteners 5, 6.
1001751 The bus bar 640 serves as a lead or terminal (Ti) to the inner end
632A of
the foil 632. The bus bar 642 serves as a lead or terminal (T2) to the outer
end 632B of the
foil 632. The electrical connection locations between the terminals Ti, T2 and
the foil 632
are spaced apart along the length of the foil 632, and are separated by turns
of the coil 630.
1001761 The bus bar 660 serves as a lead or terminal (T3) to the inner end
652A of
the foil 652. The bus bar 662 serves as a lead or terminal (T4) to the outer
end 652B of the
foil 652. The electrical connection locations between the terminals T3, T4 and
the foil 652
are spaced apart along the length of the foil 652, and are separated by turns
of the coil 650.
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[00177] The dual coil inductor assembly 600 can be used in place of the
inductor
assemblies 100 and 300. According to method embodiments, the inductor assembly
600 is
used in an AC electrical power system 11 including a phase line Li and a
neutral line N as
illustrated by the diagram in FIG. 45. The input of line Li is connected to
the terminal Ti of
the inductor assembly 600 and the output of line Li is connected to the
terminal T2 of the
inductor assembly 600. The input of the neutral line N is connected to the
terminal T3 of the
inductor assembly 600 and the output of the neutral line N is connected to the
terminal T4 of
the inductor assembly 600. In some embodiments, AC power system has a voltage
L1-N of
about 650Vrms and a load current of about 100A. Circuit breakers may be
provided between
the input terminals Ti, T3 of the inductor assembly 600 and the power supply.
The output
terminals T2, T4 of the inductor assemblies 600 may be connected to a power
distribution
panel
[00178] According to other embodiments, the inductor assembly 600 is used in a
two
phase AC electrical power system 12 as illustrated by the diagram in FIG. 46.
The input of
line Li is connected to the terminal Ti of the inductor assembly 600 and the
output of line
Li is connected to the terminal T2 of the inductor assembly 600. The input of
line L2 is
connected to the terminal T3 of the inductor assembly 600 and the output of
line L2 is
connected to the terminal T4 of the inductor assembly 600. In some
embodiments, AC
power system has a voltage L1-L2 of about 650Vrms and a load current of about
100A.
Circuit breakers may be provided between the input terminals T2, T3 of the
inductor
assembly 600 and the power supply. The output terminals Ti, T4 of the inductor
assemblies
600 may be connected to a power distribution panel.
[00179] It will be appreciated that the coils 630 and 650 are effectively
inserted into
one another. This construction can reduce the size, weight, and cost of the
inductor assembly
600 as compared to the inductor assembly 300, for example.
[00180] This construction can also improve the inductor assembly's ability to
withstand vibration.
[00181] The coils 630 and 650 are electromagnetically mutually coupled. By co-
winding the coils 630, 650 as described (i.e., spirally turning the conductor
foils 632 and 652
together), the mutual inductance and inductive electromagnetic coupling
between the coils
630, 650 is increased. This enables the combined coil 639 to achieve a greater
inductance
value using individual coils 630, 650 having lower individual inductance
values. As a result,
the coils 630, 650 can be formed with fewer turns and the size and weight of
the combined
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coil 639 can be smaller for the same overall inductance value as compared to
the inductor
assembly 300, for example.
1001821 For example, in some embodiments, the coefficient of inductive
coupling
between the coils 630 and 650 is about 0.9 versus a coefficient of inductive
coupling between
the coils 330 and 350 of about 0.13 for the inductor assembly 300. As a
result, the inductor
assembly 600 can include coils 630, 650 each having an individual inductance
value of about
500 [ill each in order to achieve an effective overall inductance on the line
L1 or the line N of
about 900 p,H.
1001831 Embodiments of the combined dual inductor assembly (e.g., the inductor
assembly 600) can provide very high voltage insulation level of around 400kV
along each
line (L1, L2, or N) and around 30kV in between the two lines (e.g., between Ll
and N or
between Li and L2).
1001841 In alternative embodiments, either (i_e_, one or both) of the
conductor foils
632, 652 can be replaced with a pair of foils in face-to-face electrical
contact as described
above for the multilayer conductor 537.
1001851 With reference to FIGS. 49 and 50, a combined dual coil inductor
assembly
700 according to further embodiments of the invention is shown therein. The
inductor
assembly 700 is constructed in the same manner as, and can be used in the same
manner as,
the dual coil inductor assembly 600, except as discussed below.
1001861 The dual coil inductor assembly 700 includes a coil assembly 731
constructed in substantially the same manner as the coil assembly 631. The
dual coil inductor
assembly 700 also includes terminal bus bars 740, 742, 760, and 762
corresponding to the
terminal bus bars 640, 642, 660, and 662.
1001871 The terminal bus bars 740, 742, 760, and 762 form terminals Ti, T2,
T3, and
T4. The terminal bus bars 740, 742, 760, and 762 are connected to the
innermost winding
736E of the first coil 730 (corresponding to the coil 630), the outermost
winding 736F of the
first coil 730, the innermost winding 736E of the second coil 750
(corresponding to the coil
650), and the outermost winding 736F of the second coil 750, respectively, in
the same
manner as described for the terminal bus bars 640, 642, 660, and 662
1001881 The dual coil inductor assembly 700 differs from the dual coil
inductor
assembly 600 in that the terminal legs Ti and T3 project from one end of the
coil assembly
631, and the terminal legs T2 and T4 project from the opposite end of the coil
assembly 631.
Thus, each of the coils 730, 750 has one of its terminal legs Ti, T4, T3, T4
on each end of
the coil assembly 731.
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1001891 With reference to FIGS. 51-54, a combined dual coil inductor assembly
800
according to further embodiments of the invention is shown therein. The
inductor assembly
800 is constructed in the same manner as, and can be used in the same manner
as, the dual
coil inductor assembly 600, except as discussed below.
1001901 The combined dual coil inductor assembly 800 includes an inner coil
830 and
an outer coil 850 that are combined or radially stacked to form a combined
coil assembly
839. The coils 830 and 850 are not co-wound as in the dual coil inductor
assembly 600.
1001911 The inductor assembly 800 includes an enclosure 810, a pair of axially
spaced apart support bases 820, a support shaft 822, an electrically
insulating fitting 824,
potting 828, insulation sleeves or tubes 829, a first or inner coil assembly
831, a second or
outer coil assembly 851, and an inter-coil electrical insulation layer 870.
The enclosure 810,
support bases 820, support shaft 822, potting 828, and insulation sleeves or
tubes 829 may be
constructed in the same manner as the enclosure 110, support bases 120,
support shaft 122,
the electrically insulating fitting 124, potting 128, and insulation sleeves
or tubes 129, for
example. The potting 828 is not shown in FIG. 54.
1001921 The inner coil assembly 831 includes a multi-layer coil 830, an inner
terminal bus bar 840, and an outer terminal bus bar 842. The inner coil
assembly 831, the
inner coil 830, the inner terminal bus bar 840, and the outer terminal bus bar
842 are
constructed substantially in the same manner as the coil assembly 131, the
inner coil 130, the
inner terminal bus bar 140, and the outer terminal bus bar 142 (FIGS. 6-10).
1001931 The inner coil 830 is an air core coil. With reference to FIG. 52, the
inner
coil 830 includes an electrically conductive conductor sheet, strip or foil
832 (corresponding
to the foil 132) and an electrically insulative insulator strip or sheet 834
(corresponding to the
insulation sheet 134). The foil 832 and sheet 834 are spirally co-wound or
wrapped about a
coil axis A-A to form windings 836, as described for the coil 130.
1001941 The inner terminal bus bar 840 includes a contact leg 840A and a
terminal leg
Ti. The contact leg 840A is secured in mechanical and electrical contact with
the innermost
winding 836E of the conductor foil 832 by a clamping member or plate 841 and
fasteners as
described above for the coil 130. The terminal leg T1 extends out of the
enclosure 810
through an opening.
1001951 The outer terminal bus bar 842 includes a contact leg 842A and a
terminal leg
T2. The contact leg 842A is secured in mechanical and electrical contact with
the outermost
winding 836F of the conductor foil 832 by a clamping member or plate 841 and
fasteners as
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described above for the coil 130. The terminal leg T2 extends out of the
enclosure 810
through an opening.
[00196] The outer coil assembly 851 includes a multi-layer coil 850, an inner
terminal bus bar 860, and an outer terminal bus bar 862. The inner coil
assembly 851, the
inner coil 850, the inner terminal bus bar 860, and the outer terminal bus bar
862 are
constructed substantially in the same manner as the coil assembly 131, the
inner coil 130, the
inner terminal bus bar 140, and the outer terminal bus bar 142 (FIGS. 6-10).
[00197] The outer coil 850 is an air core coil. With reference to FIG. 52, the
outer
coil 850 includes an electrically conductive conductor sheet, strip or foil
852 (corresponding
to the foil 132) and an electrically insulative insulator strip or sheet 854
(corresponding to the
insulation sheet 134) The foil 852 and sheet 854 are spirally co-wound or
wrapped about the
coil axis A-A to form windings 856, as described for the coil 130.
[00198] The inner terminal bus bar 860 includes a contact leg 860A and a
terminal leg
T3. The contact leg 860A is secured in mechanical and electrical contact with
the innermost
winding 856E of the conductor foil 852 by a clamping member or plate 841 and
fasteners as
described above for the coil 130. The terminal leg T3 extends out of the
enclosure 810
through an opening.
[00199] The outer terminal bus bar 862 includes a contact leg 862A and a
terminal leg
T4. The contact leg 862A is secured in mechanical and electrical contact with
the outermost
winding 856F of the conductor foil 852 by a clamping member or plate 841 and
fasteners as
described above for the coil 130. The terminal leg T4 extends out of the
enclosure 810
through an opening.
[00200] The insulation layer 870 may be tubular. The insulation layer 870
defines an
inner cavity or passage 870B. Each terminal leg Ti, T2, T3, T4 is covered by
an insulation
tube 829 that extends through the respective opening of the enclosure 810. The
insulation
tubes 829 may be constructed as described for the insulation tubes 129.
[00201] The inter-coil electrical insulation layer 870 may be formed of any
suitable
material and in any suitable form. In some embodiments, the inter-coil
electrical insulation
layer 870 is or includes a tubular layer or member of electrical insulating
material. In some
embodiments, the inter-coil electrical insulation layer 870 is or includes a
spirally wrapped or
wound sheet or web of electrical insulating material. The insulation layer 870
may be formed
a plurality of rigid insulation members that are combined to form the tubular
structure. In
some embodiments and as illustrated in FIGS. 51 and 54, the insulation layer
870 includes a
single tubular member. In some embodiments, one or more axially extending
channels 870A
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(FIG. 54) are defined in the insulation layer 870 and conformally receive the
busbars 842,
860.
1002021 The inner coil assembly 830 is mounted about or on the insulating
fitting 824
such that the fitting 824 extends through the inner passage or air core 838 of
the coil 830.
The outer coil 850 is in turn mounted about or about the inner coil 830. The
inter-coil
electrical insulation layer 870 is disposed radially between the coil
assemblies 831, 851 to
prevent electrical contact between the electrically conductive components
(i.e., the foils and
the bus bars) of the respective coils. The inner coil 830 is disposed in the
inner cavity 870B
of the insulation layer 870.
1002031 The dual coil inductor assembly 800 may be formed by winding the foil
832
and insulation layer 834 about the fitting 824 (to form the coil 830),
mounting the inter-coil
electrical insulation layer 870 over the coil 830, and winding the foil 852
and insulation layer
854 about the inter-coil electrical insulation layer 870 The foil 832 and the
foil 852 are each
wrapped around the axis A-A and, in some embodiments, are wrapped
concentrically.
1002041 The outer coil 850 circumferentially surrounds the inner coil 830.
That is,
the outer coil 850 is radially superimposed over the inner coil 830 and the
inner coil 830 is
disposed in the inner passage or air core 858 of the outer coil 850. The outer
coil 850 and the
inner coil 830 are electrically insulated from one another. The inner foil 832
is not spirally
co-wound with the outer foil 854 as in the dual coil inductor assembly 700.
The innermost
winding 856E of the foil 852 is located radially outward beyond the outermost
winding 836F
of the foil 832. The ends of the foils 832, 852 are terminated by respective
bus bars 840, 842,
860, and 862 that provide respective terminals Ti, T2, T3, and T4 to form
external
connections.
1002051 In some embodiments, the inner coil 830 and the outer coil 850 are
concentric.
1002061 As discussed above, in some embodiments the coil assemblies 831, 851
and
coils 830, 850 are constructed (including components, arrangements, materials,
dimension,
and methods of assembling) as described above with regard to the coil assembly
131 and the
coil 130.
1002071 While a separate insulation layer 870 is shown to provide electrical
insulation
between the electrically conductive components of the coil assemblies 831,
851, in other
embodiments, the insulation layer 834, 854 of one of the coils 830, 850 may be
extended to
wrap fully around the outer surface of the coil assembly 831 to electrically
insulate the coil
assembly 831 from the coil assembly 851.
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1002081 In alternative embodiments, either (i.e., one or both) of the
conductor foils
832, 852 can be replaced with a pair of foils in face-to-face contact as
described above for the
multilayer conductor 537.
1002091 The dual coil inductor assembly 800 can be used in place of the
inductor
assembly 600. According to method embodiments, the inductor assembly 800 is
used in an
AC electrical power system 11 including a phase line Li and a neutral line N
as illustrated by
the diagram in FIG. 45. The input of line Li is connected to the terminal Ti
of the dual coil
inductor assembly 800 and the output of line L1 is connected to the terminal
T2 of the dual
coil inductor assembly 800. The input of the neutral line N is connected to
the terminal T3 of
the dual coil inductor assembly 800 and the output of the neutral line N is
connected to the
terminal T4 of the dual coil inductor assembly 800. In some embodiments, AC
power system
has a voltage Li-N of about 650Vrms and a load current of about 100A. Circuit
breakers
may be provided between the input terminals Ti, T3 of the inductor assembly
800 and the
power supply. The output terminals T2, T4 of the inductor assemblies 800 may
be connected
to a power distribution panel.
1002101 According to other embodiments, the inductor assembly 800 is used in a
two
phase AC electrical power system 12 as illustrated by the diagram in FIG. 46.
The input of
line Li is connected to the terminal Ti of the dual coil inductor assembly
800and the output
of line Li is connected to the terminal T2 of the dual coil inductor assembly
800. The input
of line L2 is connected to the terminal T3 of the dual coil inductor assembly
800 and the
output of line L2 is connected to the terminal T4 of the dual coil inductor
assembly 800. In
some embodiments, AC power system has a voltage Li-L2 of about 650Vrms and a
load
current of about 100A. Circuit breakers may be provided between the input
terminals T2, T3
of the inductor assembly 800 and the power supply. The output terminals Ti, T4
of the
inductor assemblies 800 may be connected to a power distribution panel.
1002111 By surrounding the coil 830 with the coil 850 as described, the mutual
inductance and inductive coupling between the coils 830, 850 is increased.
This enables the
combined coil assembly 839 to achieve a greater inductance value using
individual coils 830,
850 having lower individual inductance values As a result, the coils 830, 850
can be formed
with fewer turns and the size and weight of the combined coil 839 can be
smaller for the
same overall inductance value as compared to the inductor assembly 300, for
example. As
discussed above with regard to the inductor assembly 600, the coefficient of
inductive
coupling between the coils 830 and 850 serves to provide a greater effective
overall
inductance on the line Li or the line N than would be achieved by the coils
830, 850
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individually. Embodiments of the combined dual inductor assembly (e.g., the
inductor
assembly 800) can also provide very high voltage insulation level of around
400kV along
each line (L1, L2, or N) and around 30kV in between the two lines (e.g.,
between Li and N
or between Li and L2).
1002121 While the arrangement of the inductor assembly 800 will also provide
improved inductive coupling (for example, inductive coupling of about 0.6), it
typically will
not be as great as that provided by the inductor assembly 600.
1002131 A dual coil inductor assembly including a coil in coil design as
described
(e.g., the dual coil inductor assembly 800) may advantageously provide lower
capacitance as
compared to the dual coil inductor assembly 600. A dual coil inductor assembly
of this
design also separates the line L and neutral N conductors, so that the risk of
short circuit
between L and Neutral is reduced or eliminated.
1002141 While inductor assemblies as shown herein and in accordance with some
embodiments are air-core (ironless) coils, according to other embodiments each
of the
inductor assemblies may a Ferromagnetic-core (e.g., an iron-core, a laminated-
core, a ferrie-
core, a powered-iron-core, a Manganese-Zinc Ferrite, a Molybdenum Permalloy
Powder
core, a Nickel-Zinc Ferrite core, a Sendust core, a Silicon Steel core, or a
Nano-crystalline
core).
1002151 The foregoing is illustrative of the present invention and is not to
be
construed as limiting thereof. Although a few exemplary embodiments of this
invention have
been described, those skilled in the art will readily appreciate that many
modifications are
possible in the exemplary embodiments without materially departing from the
teachings and
advantages of this invention. Accordingly, all such modifications are intended
to be included
within the scope of this invention as defined in the claims. The invention is
defined by the
following claims, with equivalents of the claims to be included therein.
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