Title of Invention

SUPER-CONDUCTING SYNCHRONOUS MACHINE HAVING SUPER-CONDUCTING ROTOR AND FIELD COILS.

Abstract Super conducting synchronous machine (10) having a rotor comprising: a rotor core having a rotor axis; a pair of cryogenically cold super-conducting coil windings (34,100) mounted on the rotor core, each of said coil windings in a respective plane that is parallel to and offset from the rotor axis, characterized in that each of said coil windings has an end section extending beyond an end of the rotor core, and a cryogenically cold coil support (62,64) is attached the pair of cryogenically cold coil windings to form an assembly of coil support and coil windings, and said assembly is separated from said rotor core by a gap.
Full Text BACKGROUND OF THE INVENTION
The present invention relates generally to a super-conductive coil in a synchronous
rotating machine. More particularly, the present invention relates to a support
structure for super-conducting field windings in the rotor of a synchronous machine.
Synchronous electrical machines having field coil windings include, but are not
limited to, rotary generators, rotary motors, and linear motors. These machines
generally comprise a stator and rotor that are electromagnetically coupled. The rotor
may include a multi-pole rotor core and coil windings mounted on the rotor core. The
rotor cores may include a magnetically-permeable solid material, such as an iron-core
rotor.
Conventional copper windings are commonly used in the rotors of synchronous
electrical machines. However, the electrical resistance of copper windings (although
low by conventional measures) is sufficient to contribute to substantial heating of the
rotor and to diminish the power efficiency of the machine. Recently, super-
conducting (SC) coil windings have been developed for rotors. SC windings have
effectively no resistance and are highly advantageous rotor coil windings.
Iron-core rotors saturate at air-gap magnetic field strength of about 2 Tesla. Known
super-conductive rotors employ air-core designs, with no iron in the rotor, to achieve
air-gap magnetic fields of 3 Tesla or higher, which increase the power density of the
electrical machine and result in significant reduction in weight and size. Air-core
super-conductive rotors, however require large amounts of super-conducting wire,
which adds to the number of coils required, the complexity of the coil supports, and
the cost. Such super-conductive rotors have their super-conducting coils cooled by
liquid helium, with the used helium cooled being returned as room-temperature
gaseous helium. Using liquid helium for cryogenic cooling requires continuous
reliquefaction of the returned, room- temperature gaseous helium, and such
reliquetaction poses significant reliability problems and requires significant auxiliary
power.
High temperature SC coil field windings are formed of super-conducting materials
that are brittle, and must be cooled to a temperature at or below a critical temperature,
e.g., 27°K, to achieve and maintain super-conductivity. The SC windings may be
formed of a high temperature super-conducting material, such as a BSCCO
(BixSrxCaxCuxOx) based conductor.
SC coil cooling techniques include cooling an epoxy-impregnated SC coil through a
solid conduction path from a cryocooler. Alternatively, cooling tubes in the rotor may
convey a liquid and'or gaseous cryogen to a porous SC coil winding that is immersed
in the flow of the liquid and/or gaseous cryogen. However, immersion cooling
requires the entire field winding and rotor structure to be at cryogenic temperature.
As a result, no iron can be used in the rotor magnetic circuit because of the brittle
nature of iron at cryogenic temperatures.
What is needed is a super-conducting field winding assemblage for an electrical
machine that does not have the disadvantages of the air-core and liquid-cooled super-
conducting field winding assemblages of, for example, known super-conductive
rotors.
In addition, high temperature super-conducting (HTS) coils are sensitive to
degradation from high bending and tensile strains. These coils must undergo
substantial centrifugal forces that stress and strain the coil windings. Normal
operation of electrical machines involves thousands of start-up and shut-down cycles
over the course of several years that result in low cycle fatigue loading of the rotor.
Furthermore, the HTS rotor winding must be capable of withstanding 25% overspeed
operation during rotor balancing at ambient temperature and occasional over-speed at
cryogenic temperatures during operation. These overspeed conditions substantially
increase the centrifugal force loading on the windings over normal operating
conditions.
HTS coils used as the rotor field winding of an electrical machine are subjected to
stresses and strains during cool-down and normal operation as they are subjected to
centrifugal loading, torque transmission, and transient fault conditions. To withstand
the forces, stresses, strains and cyclical loading, the HTS coils must be properly
supported in the rotor. These support systems and structures that hold the coils in the
rotor should secure the coils against the tremendous centrifugal forces due to the
rotation of the rotor. Moreover, these support systems and structures should protect
the HTS coils and ensure that the coils do not crack, fatigue or otherwise break.
Developing support systems for HTS coil has been a difficult challenge in adapting
SC coils to rotors. Examples of HTS coil support systems for rotors that have
previously been proposed are disclosed in U.S. Patents Nos. 5,548,168; 5,532,663;
5,672,921; 5,777,420; 6,169,353, and 6,066,906. However, these coil support
systems suffer various problems, such as being expensive, complex and requiring an
excessive number of components. There is a long-felt need for a rotor and coil
support system tor a HTS coil in a synchronous machine. The need exists tor HTS
coil support system made with low cost and easy-to-fabricate components.
BRIEF SUMMARY OF THE INVENTION
A rotor having twin HTS coils on a rotor core of a synchronous machine. Similarly, a
support structure is disclosed for mounting the pair of HTS coils on the rotor. The
rotor may be for a synchronous machine originally designed to include HTS coils.
Alternatively, the HTS rotor may replace a copper coil rotor in an existing electrical
machine, such as in a conventional generator. The rotor and its HTS coils that are
described here in the context of a generator, but the HTS coil rotor is also suitable for
use in other synchronous machines.
A dual racetrack HTS coil design for two-pole field winding provides several
advantages including simplicity in coil design and in coil support design. In addition,
a dual coil design has substantially twice the amount of coil winding of a single-coil
rotor. Thus, a dual coil design has a substantially greater capacity for power
generation (when the coil is incorporated in a rotor of a generator).
In a first embodiment, the invention is a rotor for a synchronous machine comprising:
(i) a rotor core having a rotor axis; and (ii) a pair of super-conducting coil windings
mounted on the rotor core, each of said coil windings in a respective plane that is
parallel to and offset from the rotor axis.
In another embodiment, the invention is a rotor for a synchronous machine
comprising, (i) a rotor core having a rotor axis and recessed surfaces extending
longitudinally along the rotor core; (ii) a first and second super-conducting coil
windings mounted on the rotor core, each of said coil windings being in a plane that is
parallel to and offset from the rotor axis; (iii) a plurality of first tension rods spanning
and connecting opposite side sections of each of said coil windings, and (iv) a
plurality of second tension rods spanning between and connecting both of the coil
windings.
BRIEF DESCRIPTION OF THEAccompanying RAWINGS
The accompanying drawings in conjunction with the text of this specification describe
an embodiment of the invention.
FIGURE 1 is a schematic side elevational view of a super-conductive (SC) rotor
shown within a stator.
FIGURE 2 is a schematic perspective view of a high temperature super-conducting
(HTS) racetrack coil suitable for use in the SC rotor shown in Figure 1.
FIGURE 3 is a schematic perspective view of an exemplary SC rotor with dual HTS
racetrack coils (without a coil support system).
FIGURE 4 is a schematic perspective view of an exemplary SC rotor with dual HTS
racetrack coils (with a coil support system).
FIGURE 5 is a schematic perspective view of an exemplary SC rotor with dual saddle
coils (without a coil support system).
FIGURE 6 is a schematic of a coil housing for dual saddle coils.
DETAILED DESCRIPTION OF THE INVENTION
FIGURE 1 shows an exemplary synchronous generator machine 10 having a stator 12
and a rotor 14. The stator (illustrated by dotted lines) includes field winding coils that
surround the cylindrical rotor cavity 16 of the stator. The rotor fits inside the rotor
cavity of the stator. As the rotor turns within the stator, a magnetic field 18 generated
by the rotor and rotor coils moves through the stator and creates an electrical current
in the windings of the stator coils. This current is output by the generator as electrical
power.
The rotor 14 has a generally longitudinally-extending axis 20 and a generally solid
rotor core 22. The solid core 22 has high magnetic permeability, and is usually made
of a ferromagnetic material, such as iron In a low power density super-conducting
machine, the iron core of the rotor is used to reduce the magnetomotive force (MMF),
and, thus, the wire usage. For example, the iron rotor core can be magnetically
saturated at an air-gap magnetic field strength of about 2 Tesla.
The rotor 14 supports a generally a pair of longitudinally-extending, racetrack-shaped
high temperature super-conducting (FITS) coils (See Fig. 3). The super-conductive
coil may be alternatively a saddle-shape or have some other shape that is suitable for a
particular rotor design. The coil support system disclosed here may be adapted for
coil configurations other than a racetrack coil shape.
The rotor includes a pair of end shafts 24, 30 that brace the core 22 and are supported
by bearings and can be coupled to external devices. The collector end shaft 24
includes a collector rings 79 that provide an external electrical connection for the
connections 79 on the coil 36 of the coil winding 34. In addition, the collector end
shaft has a cryogen transfer coupling 26 to a source of cryogenic cooling fluid used to
cool the SC coil windings in the rotor. The cryogen transfer coupling 26 includes a
stationary segment coupled to a source of cryogen cooling fluid and a rotating
segment which provides cooling fluid to the HTS coil. The drive end shaft 30
includes a power coupling 32 to a driving turbine, for example.
FIGURE 2 shows an exemplary HTS racetrack field coil winding 34. The SC field
winding coils 34 of the rotor includes a high temperature super-conducting (HTS) coil
36. Each HTS coil includes a high temperature super-conducting conductor, such as a
BSCCO (BixSrxCayCuxOx) conductor wires laminated in a solid epoxy impregnated
winding composite. For example, a series of B2S2C2C3O wires can be laminated and
bound in a solid epoxy impregnated coil.
HTS wire is brittle and easy to be damaged. The HTS coil is typically layer wound
with HTS tape, and is epoxy impregnated in a precision coil form to attain close
dimensional tolerances. The tape is wound around in a helix to form a racetrack SC
coil 36. The wire is wrapped to form a racetrack winding that includes cooling
conduits that are bonded on one or more outside coil surfaces to provide cooling by
conduction heat transfer. In the saddle coil embodiment, the tape may be arranged so
that it is oriented radially with respect to the rotor.
The dimensions of the racetrack coil are dependent on the dimensions of the rotor
core. Generally, each racetrack coil encircles the magnetic poles of the rotor core,
and is parallel to the rotor axis. The HTS coil windings are continuous around the
racetrack. The coils form a resistance-free current path around the rotor core and
between the magnetic poles of the core.
Fluid passages 38 for cryogenic cooling fluid are included in the coil winding 34.
These passages may extend around an outside edge of the SC coil 36. The
passageways provide cryogenic cooling fluid to remove heat from those coils by
conduction heat transfer. The cooling fluid maintains the low temperatures, e.g.,
27°K, in the SC coil winding needed to promote super-conducting conditions,
including the absence of electrical resistance in the coil. The cooling passages have
an input ports 31 and output ports 41 at one end of the rotor core. These ports 39,41
connect to cooling passages 38 on the SC coil to the cryogen transfer coupling 28
Each HTS racetrack coil winding 34 has generally-straight side portions 40 parallel to
a rotor axis 20 and end portions 40 that are perpendicular to the rotor axis. The side
portions of the coil are subjected to the greatest centrifugal stresses because they are
the portions of the coil furthest from the rotor axis. Accordingly, these side portions
of the coil are supported by a support system (shown in Figs. 3 and 4) that secures the
side portions of the coil and counteract the centrifugal forces that act on the coil side
portions.
FIGURE 3 is a schematic diagram of a rotor core 22 with dual HTS racetrack coil
windings 34. The end shafts 24, 30 extend from opposite ends of the rotor core. The
rotor core may be an iron forging having desirable magnetic characteristics, such as
high magnetic flux permeability. The rotor core may have two magnetic poles,
wherein the poles are at opposite ends of the rotor core. The rotor core
electromagnetically interacts with the coil windings to promote the electromagnetic
fields around the rotor and stator.
The rotor core and end shafts may be integrally formed, e.g., by forging, from a single
iron shaft. Alternatively, the rotor core and end shafts may be discrete components
(and even the core may be a multi-piece core) that are assembled together. The core
forging may be made into three pieces to facilitate rotor assembly. However, in the
example shown here, the rotor core is integral with the end shafts, and the core and
shafts are continuous along the entire length of the rotor. Alternatively, the iron rotor
core may be made of multiple sections along shaft longitudinal direction.
The iron rotor core 22 has a generally cylindrical shape suitable for rotation within the
stator 12. To receive the coil windings, the rotor core has recessed surfaces 44, such
as flat or triangular regions or slots, formed in the curved surface of the cylindrical
core and extending longitudinally across the rotor core. The coil windings 34 are
mounted on the rotor adjacent these recessed areas. The coils generally extend
longitudinally along an outer surface of the recessed area. These recessed surfaces 44
on the rotor core are intended to receive the coil windings and, thus, the shape of the
recess is designed to conform to the coil winding. For example, if the coil winding
has a saddle-shape or some other shape, the recess(es) in the rotor core would be
configure to receive the shape of the winding.
The recessed surfaces 44 in the rotor core receive the coil windings such that the
outer-surfaces of the coil windings extend to substantially an envelope defined by the
rotation of the rotor. The outer curved surfaces 46 of the rotor core when rotated
define a cylindrical envelope. This rotation envelope of the rotor has substantially the
same diameter as the rotor cavity 16 (see Fig. 1) in the stator.
The gap between the rotor envelope and stator cavity is a relatively-small clearance as
required for forced flow ventilation cooling of the stator only, since the rotor requires
no ventilation cooling. It is desirable to minimize the clearance between the rotor and
stator so as to increase the electromagnetic coupling between the rotor coil windings
and the stator windings. Moreover, the rotor coil windings are preferably positioned
such that they extend to the envelope formed by the rotor and, thus, are separated
from the stator by only the clearance gap between the rotor and stator.
In a dual HTS coil winding arrangement, the rotor core 22 has two pair of recess
surfaces 44 for the twin coils. These four recessed surfaces are symmetrically
arranged around me rolor core periphery to provide balance during rota lion These
surfaces 44 each define a volume 48 in the rotor core extending the length of the rotor
core that has a generally right-angled triangular cross section. The hypotenuse of this
triangular cross section is an arc of the surface 46 of the rotor core. Each volume 48
receives a side portion 40 of one of the two HTS coil windings 34. The warm iron
core 22 has an array of conduit apertures 48 to allow the tension bars to extend
through the rotor.
A pair of rotor core ridges 50 extend longitudinally along the rotor and on opposite
sides of the rotor. The pair of ridges extends radially outward on the rotor to the
envelope formed by the rotation of the rotor. Each core ridge is between the two coils
34 and the recessed surfaces 44 on which the coils are mounted. The ridges are
integral to the rotor core and formed of the same magnetic permeable material as is
other portions of the rotor core. The ridges are designed to enhance the bending
stiffness of the rotor about the pole axis as required to reduce the twice per revolution
vibration of the rotor.
The principal loading of the HTS coil in an iron core rotor is from centrifugal
acceleration during rotor rotation. An effective coil structural support is needed to
counteract the centrifugal forces. The coil support is needed especially along the side
sections 40 of the coil that experience the most centrifugal acceleration. To support
the side sections of coils, tension rods (see Fig. 4) span between the coils and grasp
opposite side sections of a coil. The tension rods may also extend between the pair of
coils to provide support between the dual coils. The tension rods extend through
conduits 52, e.g., apertures, in the rotor core so that they may span between side
sections of the same coil or between adjacent coils the tension rods.
The conduits 52 are generally cylindrical passages in the rotor having a straight axis.
The diameter of the conduits may be sufficiently larger than the diameter of the
tension rods so as to avoid having the rotor contact the tension rods and, thus, avoid
thermal conduction heat transfer between the rotor and the rods. The diameter of the
conduits is substantially constant, except at their ends near the recessed surfaces of the
rotor. At their ends, the conduits may expand to a larger diameter to accommodate a
cylindrical sleeve (see Fig. 4) for the tension rods.
The conduits 52 are apertures, i.e., holes, that extend through the rotor core and
provide a passageway for the tension rods. The conduits have a generally-circular
diameter and a straight axis through the rotor. The axis of the conduits are generally
in a plane defined by the racetrack coil to which the conduit corresponds. In addition,
the axis of the conduit is perpendicular to the side sections of the coil to which are
connected the tension rod that extends through the conduit. Further, the diameter of
the rotor conduits are sufficiently large such than the tension rods need not contact the
rotor. Avoiding contact between the tension rods and the rotor core minimizes the
conduction of heat from the rotor core, through the tension rods and to the cooled SC
coil windings.
The conduits 52 may be perpendicular to the side sections 40 of the coil. For those
tension rods that span between opposite side sections of the same coil, the
corresponding conduits are in the same plane as that coil For those tension rods that
extend between the dual coils, the corresponding conduits may be perpendicular to the
plane of both coils and extend through the ridges 50 of the rotor core. The number of
conduits and the location of the conduits will depend on the location of the HTS coils
and the number of coil housings (see Fig. 4) needed to support the side sections of the
coils.
As shown in FIGURE 4, the end sections 42 of each of the pair of coil windings 34
are adjacent opposite ends of the rotor core. A split-clamp 54 (Fig. 4) holds the end
section of the coil windings. The split clamp includes a pair of plates between which
are sandwiched the end section of a coil. The split clamp may be formed of a non-
magnetic material, such as Inconel X718. The same or similar non-magnetic
materials may be used to form the tension rods, and other portions of the support
system. The support system is preferably non-magnetic so as to preserve ductility at
cryogenic temperatures, since ferromagnetic materials become brittle at temperatures
below the Curie transition temperature and cannot be used as load carrying structures.
The split clamp 54 at each end of the coil winding includes a pair of opposite plates
56 between are sandwiched the end section 42 of the coil. The surfaces of the clamp
plates 56 includes channels 58 to receive the end sections of the coil windings. The
split clamp may be supported by a collar (not shown) or other structural device that
holds the clamp to the rotor core and enables the clamp to support the end sections of
the HTS coils.
The electrical and cooling fluid couplings 39 (only the electrical coupling is shown in
Figures 3 and 4) to the coils are at the coil end sections 42. An electrical coupling to
the coil is provided at the end section nearest the end shaft having a collector (not
shown) for providing electrical connection to the rotating coils on the rotor. A
cooling fluid coupling is provided at the opposite end section of each coil winding so
that cryogenic cooling fluid can flow to the coils and heat been removed from the
coils in the cooling fluid that is circulated back from the coils and to the cooling
system.
The side sections 40 of the racetrack-shaped HTS coil 34 are supported by a series of
tension rods 62 that extend through the conduits 52 in the rotor core body. The
tension rods are non-magnetic, straight bars that extend between opposite side
sections of the same coil, or between side sections of the two coils. The tension rod
may be formed of a high strength non-magnetic alloys, such as Inconel X718. The
tension rods have at each end a coupling with a channel housing 64 that hold the coil
winding. The channel housings and the tension rods provide adjustment of the
tension applied to the side sections of the coil windings.
The coil winding supports hold the coil windings on the rotor, and buttress the
windings against the centrifugal forces and vibrations resulting from the rotation of
the rotor and operation of the electrical machine. The coil winding supports include
tension rods that extend through the rotor and clamp onto the coil windings at both
ends of the rod. The tension rods support the coil especially well with respect to
centrifugal forces as the rods extend substantially radially to the coil winding. Each
tension rod is a shaft with continuity along the longitudinal direction of the rod and in
the plane of the racetrack coil. The longitudinal continuity of the tension rods
provides lateral stiffness to the coils which provides rotor dynamics benefits.
Moreover, the lateral stiffness permits integrating the coil support with the coils so
that the coil can be assembled with support prior to final rotor assembly. Pre-
assembly of the coil and coil support reduces production cycle, improves coil support
quality, and reduces coil assembly variations. The racetrack coil is supported by an
array of tension members that span the long sides of the coil. The tension rod coil
support members are pre-assembled to coil.
The HTS coil and structural support components are at cryogenic temperature. In
contrast, the rotor core is at ambient "hot" temperature. The coil supports are
potential sources of thermal conduction that would allow heat to reach the HTS coils
from the rotor core. The rotor becomes hot during operation. As the coils are to be
held in super-cooled conditions, heat conduction into the coils is to be avoided. The
rods extend through apertures, e.g., conduits, in the rotor but are not in contact with
the rotor. This lack of contact avoids the conduction of heat from the rotor to the
tension rods and coils.
To reduce the heat leaking away from the coil, the coil support is minimized to reduce
the thermal conduction through support from heat sources such as the rotor core.
There are generally two categories of support for super-conducting winding:
(i) "warm" supports and (ii) "cold" supports. In a warm support, the supporting
structures are thermally isolated from the cooled SC windings. With warm supports,
most of the mechanical load of a super-conducting (SC) coil is supported by structural
members spanning from cold to warm members.
In a cold support system, the support system is at or near the cold cryogenic
temperature of the SC coils. In coid supports, most of the mechanical load of a SC
coil is supported by structural members which are at or near a cryogenic temperature.
The exemplary support system disclosed here are cold supports in that the tension
rods and associated housings the coupled the tension rods to the SC coil windings are
maintained at or near a cryogenic temperature. Because the supporting members are
cold, these members are thermally isolated, e.g., by the non-contact conduits through
the rotor core, from other "hot" components of the rotor.
An individual support member consists of a tension rod 62, a channel housing 64, and
a dowel pin 66 that connects the housing to the end of the tension rod. Each channel
housing 64 is a U-shaped bracket having legs that connect to a tension rod and a
channel to receive the coil winding 34. The U-shaped housing allows for the precise
and convenient assembly of the support system for the coil. The channel housings
collectively distributes the forces that act on the coil, e.g., centrifugal forces, over
substantially the entire side sections 40 of each coil.
The channel housings 64 collectively extend the length of each of the side sections 40
of the HTS coils 34. The channel housings prevent the side sections of the coils from
excessive flexing and bending due to centrifugal forces. The coil supports do not
restrict the coils from thermal expansion and contraction that occur during normal
start/stop operation of the gas turbine. In particular, the thermal expansion causes the
length of the side sections to increase or decrease and, thus, slide longitudinally with
respect to the support system.
The transfer of the centrifugal load from the coil structure to a support rod is through
a U-shaped housing that fits around the coil outside surface and side straight sections,
and is doweled 66 to a wide diameter end 68 of the tension rod. The U-shaped
housing is formed of a light, high strength material that is ductile at cryogenic
temperatures. Typical materials for channel housing are aluminum, Inconel, or
titanium alloys, which are non-magnetic. The shape of the U-shaped housing can be
optimized for low weight.
The dowel pin 66 through the U-shaped housing and tension rod may be hollow for
low weight. Locking nuts or pins are threaded or attached at the ends of the dowel pin
to secure the U-shaped housing sides from spreading apart under load The dowel pin
can be made of high strength Inconel or titanium alloys. The tension rods are made
with larger diameter ends 68 that are machined with two fiats 70 at their ends to fit the
U-shaped housing and coil width. The flat ends 70 of the tension rods abut against
the inside surface of the HTS coils, when the rod, coil and housing are connected
together. This construction reduces the stress concentration in the region of the
tension rod hole that receives the dowel.
The tension rods 72 that extend between adjacent coils also attach to the U-shaped
channel housings 64. These tension rods provide a framework to support the dual
coils with respect to each other. The tension rods 72 insert into female connectors 74
in the sides of each channel housing. A locking dowel 74 may be used to secure the
tension rod 76 to the side of the channel housing.
The coil support system of tension rods 62, channel housings 64 and split-clamp 54
may be assembled as the HTS coil windings 34 are mounted on the rotor core 22.
Indeed, the coil support system is largely the means by which the HTS coil windings
are attached to the rotor core. The frame of tension rods and channel housings
provides a fairly ridged structure for supporting the coil windings and holding the coil
windings in place with respect to the rotor core.
The coil winding 34 may be shielded from stator-induced magnetic flux by a
conductive cylinder around the rotor core. In addition, the coil winding may be in a
vacuum to insulate the winding from the heat of the rotor. The vacuum may be
formed by a cylindrical vacuum vessel around the rotor core.
FIGURE 5 is a schematic view of dual saddle coil 100 mounted on a rotor 20. The
saddle coils each have a similar construction to the racetrack winding shown in Figure
2, in that each coil is formed of wrapped SC coil 36 and has a cooling passage 38 for
maintaining the coil at cryogenic temperatures. The saddle coils have a long side
section 140 that fit into a longitudinal slot 102 in the rotor core. The slots extend the
length of the core 22, and are each on opposite sides of the core. The saddle coils
have end sections 154 that are adjacent the ends 56 of the rotor core. Thus, the saddle
coils each extend through the pair of slots in the core and wrap around the ends of the
core. A shield 90 covers the coils and provides a vacuum for the coils, and is
conductive to prevent electromagnetic fields from the stator from penetrating the
sensitive coils.
FIGURE 6 is a schematic diagram of a coil housing 144 for the dual saddle coils 100.
The coil housing is similar to the housing 44 for the racetrack coil windings, except
that the saddle housing 144 fits over a pair of windings. The saddle housing has a pair
of legs 150 each with an aperture 152 to receive a dowel 180. The dowel connects the
housing to a tension rod 142 that extends through a conduit in the core. The end 186
of the tension rod is flat and forms a support surface for the sides of the saddle coils
facing the core.
While the invention has been described in connection with what is presently
considered to be the most practical and preferred embodiment, it is to be understood
that the invention is not to be limited to the disclosed embodiment, but on the
contrary, is intended to cover body, and the coil winding having side sections adjacent
the flat surfaces.
We claim:
1. Super conducting synchronous machine (10) having a rotor comprising:
a rotor core having a rotor axis;
a pair of cryogenically cold super-conducting coil windings (34,100) mounted on
the rotor core, each of said coil windings in a respective plane that is parallel to
and offset from the rotor axis, characterized in that each of said coil windings
has an end section extending beyond an end of the rotor core, and
a cryogenically cold coil support (62,64) is attached the pair of cryogenically cold
coil windings to form an assembly of coil support and coil windings, and said
assembly is separated from said rotor core by a gap.
2. The super conducting synchronous machine (10) as claimed in claim 1
wherein the super-conducting coils (34) have a race-track shape.
3. The super conducting synchronous machine (10) as claimed in claim 1
wherein the super-conducting coils each have a pair of opposite side sections
(40) that are parallel to the rotor axis and coupled to the end section.
4. The super conducting synchronous machine (10) as claimed in claim 1
wherein the rotor core (22) has recessed surface (44) extending longitudinally
along the rotor core and said recessed surfaces receive the coil windings
(34,100).
5. The super conducting synchronous machine (10) as claimed in claim 1
wherein the super-conduction coils (34,100) included a high temperature super-
conducting (HTS) wire (36) extending round the entire coil.
6. The super conducting synchronous machine (10) as claimed in claim 1
further comprising tension rods (72) extending between and connecting the coil
windings.
7. The super conducting synchronous machine (10) as claimed in claim 1
further comprising tension rods (72) extending between and connecting the coil
windings, and extending through conduits (52) in the rotor core.
8. The super conducting synchronous machine (10) as claimed in claim 1
further comprising tension rods (72) extending between and connecting the coil
windings (34) and wherein said tension rods are perpendicular to the respective
planes of the coils.
9. The super conducting synchronous machine (10) as claimed in claim 1
wherein the rotor core (23) is an iron core body.
10. The super conducting synchronous machine (10) as claimed in claim 1
wherein the rotor core (22) includes a ridge (50) separating the coil windings.
11. The super conducting synchronous machine (10) as claimed in claim 1
further comprising tension rods (62) spanning and connected to opposite side
sections of each coil (34), and tension rods (72) spanning and connected to both
of said coils.
12. The super conducting synchronous machine (10) as claimed in claim 1
wherein the coil windings (34,100) are on opposite sides of the rotor axis, and an
equal distance separates the plane for each of said coil windings and the rotor
axis.
13. The super conducting synchronous machine (10) as claimed in claim 1
wherein the planes for each of said coil windings (34,100) are parallel to each
other, and the rotor axis is between said planes.
14. The super conducting synchronous machine (10) as claimed in claim 1
wherein the coils are saddle coils (100).
15. The super conducting synchronous machine (10) as claimed in claim 14
further comprising saddle coil housing (44) that each bracket side sections of
both coils.
16. The super conducting synchronous machine (10) as claimed in claim 1
wherein the rotor core (22) has recessed surfaces (144) extending longitudinally
along the rotor core, and the rotor further comprises:
a plurality of first tension rods (62) spanning and connecting opposite side
sections of each of said coil windings, and
a plurality of second tension rods (72) spanning between and connecting both of
the coil windings.
17. The super conducting synchronous machine (10) as claimed in claim 16
further comprising a plurality of channel housings (70) each supporting a section
of the side section of said coil winding and connected to an end of one of said
first tension rods and one of said second tension rods.
18. The super conducting synchronous machine (10) as claimed in claim 17
wherein the channel housing (70) form a housing covering the side section
entirely.
19. The super conducting synchronous machine (10) as claimed in claim 17
wherein the first and second tension bars each extend through respective
conduits (52) in the rotor core.
20. The super conducting synchronous machine (10) as claimed in claim 16
wherein the coils are saddle coils (100).
21. The super conducting synchronous machine (10) as claimed in claim 20
further comprising saddle coil housings (144) that each bracket side sections of
both coils.

Super conducting synchronous machine (10) having a rotor comprising:
a rotor core having a rotor axis; a pair of cryogenically cold super-conducting coil
windings (34,100) mounted on the rotor core, each of said coil windings in a
respective plane that is parallel to and offset from the rotor axis, characterized in
that each of said coil windings has an end section extending beyond an end of
the rotor core, and a cryogenically cold coil support (62,64) is attached the pair
of cryogenically cold coil windings to form an assembly of coil support and coil
windings, and said assembly is separated from said rotor core by a gap.

Documents:

247-cal-2002-abstract.pdf

247-cal-2002-assignment.pdf

247-cal-2002-claims.pdf

247-cal-2002-correspondence.pdf

247-cal-2002-description (complete).pdf

247-cal-2002-examination report.pdf

247-cal-2002-form 1.pdf

247-cal-2002-form 18.pdf

247-cal-2002-form 2.pdf

247-cal-2002-form 3.pdf

247-cal-2002-form 5.pdf

247-CAL-2002-FORM-27.pdf

247-cal-2002-gpa.pdf

247-cal-2002-granted-abstract.pdf

247-cal-2002-granted-assignment.pdf

247-cal-2002-granted-claims.pdf

247-cal-2002-granted-correspondence.pdf

247-cal-2002-granted-description (complete).pdf

247-cal-2002-granted-drawings.pdf

247-cal-2002-granted-examination report.pdf

247-cal-2002-granted-form 1.pdf

247-cal-2002-granted-form 18.pdf

247-cal-2002-granted-form 2.pdf

247-cal-2002-granted-form 3.pdf

247-cal-2002-granted-form 5.pdf

247-cal-2002-granted-gpa.pdf

247-cal-2002-granted-reply to examination report.pdf

247-cal-2002-granted-specification.pdf

247-cal-2002-others.pdf

247-cal-2002-reply to examination report.pdf

247-cal-2002-specification.pdf


Patent Number 235598
Indian Patent Application Number 247/CAL/2002
PG Journal Number 28/2009
Publication Date 10-Jul-2009
Grant Date 08-Jul-2009
Date of Filing 30-Apr-2002
Name of Patentee GENERAL ELECTRIC COMPANY
Applicant Address ONE RIVER ROAD, SCHNECTADY, NEW YORK 12345, USA.
Inventors:
# Inventor's Name Inventor's Address
1 YU WANG SPRUCE STREET, CLIFTON PARK, NEW YORK 12065
2 JAMES PELLEGRINO ALEXANDER 12 NORTHWEST PAST, BALLSTON LAKE, NEW YORK 12019
3 YU WANG SPRUCE STREET, CLIFTON PARK, NEW YORK 12065
4 JAMES PELLEGRINO ALEXANDER 12 NORTHWEST PAST, BALLSTON LAKE, NEW YORK 12019
PCT International Classification Number H02K 3/04
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 09/854,931 2001-05-15 U.S.A.