GB1564646A - Cryogenically cooled electrical apparatus - Google Patents
Cryogenically cooled electrical apparatus Download PDFInfo
- Publication number
- GB1564646A GB1564646A GB49253/77A GB4925377A GB1564646A GB 1564646 A GB1564646 A GB 1564646A GB 49253/77 A GB49253/77 A GB 49253/77A GB 4925377 A GB4925377 A GB 4925377A GB 1564646 A GB1564646 A GB 1564646A
- Authority
- GB
- United Kingdom
- Prior art keywords
- coolant
- ducts
- shield
- magnetic
- magnetic shield
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000002826 coolant Substances 0.000 claims description 81
- 238000004804 winding Methods 0.000 claims description 31
- 239000000463 material Substances 0.000 claims description 15
- 229910052734 helium Inorganic materials 0.000 claims description 6
- 239000001307 helium Substances 0.000 claims description 6
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 6
- 239000004020 conductor Substances 0.000 claims description 4
- 239000010949 copper Substances 0.000 claims description 4
- 229910052802 copper Inorganic materials 0.000 claims description 4
- 230000004941 influx Effects 0.000 claims description 4
- 239000007788 liquid Substances 0.000 claims description 4
- 238000005192 partition Methods 0.000 claims description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 2
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims description 2
- 239000004411 aluminium Substances 0.000 claims description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 2
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- 150000001879 copper Chemical class 0.000 claims description 2
- 230000008878 coupling Effects 0.000 claims description 2
- 238000010168 coupling process Methods 0.000 claims description 2
- 238000005859 coupling reaction Methods 0.000 claims description 2
- 238000001704 evaporation Methods 0.000 claims description 2
- 239000000696 magnetic material Substances 0.000 claims description 2
- 239000010955 niobium Substances 0.000 claims description 2
- 229910052758 niobium Inorganic materials 0.000 claims description 2
- 230000002093 peripheral effect Effects 0.000 claims description 2
- 238000004544 sputter deposition Methods 0.000 claims description 2
- 229940071182 stannate Drugs 0.000 claims description 2
- 239000010936 titanium Substances 0.000 claims description 2
- 229910052719 titanium Inorganic materials 0.000 claims description 2
- 229910052726 zirconium Inorganic materials 0.000 claims description 2
- 230000000694 effects Effects 0.000 description 4
- 238000009413 insulation Methods 0.000 description 4
- 238000001816 cooling Methods 0.000 description 3
- 238000009434 installation Methods 0.000 description 2
- 239000002887 superconductor Substances 0.000 description 2
- -1 e.g. Substances 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K55/00—Dynamo-electric machines having windings operating at cryogenic temperatures
- H02K55/02—Dynamo-electric machines having windings operating at cryogenic temperatures of the synchronous type
- H02K55/04—Dynamo-electric machines having windings operating at cryogenic temperatures of the synchronous type with rotating field windings
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K9/00—Arrangements for cooling or ventilating
- H02K9/19—Arrangements for cooling or ventilating for machines with closed casing and closed-circuit cooling using a liquid cooling medium, e.g. oil
- H02K9/20—Arrangements for cooling or ventilating for machines with closed casing and closed-circuit cooling using a liquid cooling medium, e.g. oil wherein the cooling medium vaporises within the machine casing
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/60—Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Superconductive Dynamoelectric Machines (AREA)
- Motor Or Generator Cooling System (AREA)
Description
(54) IMPROVEMENTS IN CRYOGENICALLY
COOLED ELECTRICAL APPARATUS
(71) We, SPETSIALNOE KON
STRUKTORSKOE BJURO "ENER
GOKHIMMASH", of prospekt Nauki, 1.
Novosibirsk, USSR., and LENINGRADS
KOW PROIZVODSTVENNOE ELEK
TROMASHINOSTROITELNOE
OBIEDINENIE "ELEKTROSILA"., of
Moskovsky prospect, 158, Leningrad,
USSR., both USSR corporate bodies., do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement:
The present invention relates to electrical apparatus and more particularly to cryogenically cooled electrical apparatus including machines.
The invention is suitable for use in all kinds of electrical machines: electric motors, generators and converters employed in nuclear, thermal and other power plants or in vehicular transport and on aircraft. The present invention may also find extensive application in power plants for use in outer space. The invention may also be used to advantage in other equipment and installations utilizing the phenomenon of superconduction, to shield the superconductor from the effect of time-varying magnetic fields.
Cryogenically cooled electrical machines of conventional design are known to have a superconductive field winding fixed to a hollow rotor enclosed in a hermetically sealed heat-insulating shell enclosing a protective vacuum. The superconducting field winding has a cryogenic cooling system. The low-temperature zone of the superconducting field winding needs thermal insulation, for it has to be protected against convective and radiant influx of heat and, also, against the effect of the variable distribution of the magnetic field at the armature winding side due to the harmonic and subharmonic components of the magnetic field, which induces an alternating current of at least six times the nominal frequency within the field winding. This results in additional losses in the superconductive winding.
Superconductors of the second order, while allowing high induction, are subject to comparatively high a.c. losses. Available data on those losses is rather contradictory.
Yet, even if those losses be scores of thousands of times smaller than those occuring at room temperature, the power losses within the cryogenic system of cooling still remain substantial.
To reduce the convective component of the heat influx use is made of vacuum insulation provided, as a general rule, by two annular vacuum gaps, and the radiant component is reduced by installing heat shields within the annular gaps. The superconductive field winding is protected against the effect of the varying distribution of the magnetic flux by the installation of an additional magnetic shield made either of a material of high electric and thermal conductivity, or of a superconductive material.
A cryogenically cooled electrical machine known in the art comprises a superconductive field winding placed in a hollow rotor surrounded by a magnetic shield formed of a superconductive material.
The magnetic shield of the known machine is made up of long superconductive fibres enclosed in a sheathing of a material having a high thermal conductivity. The shield is arranged directly on the outer surface of the rotor and is cooled by virtue of its being coupled, by its thermal conductance, with the superconductive winding of the rotor.
Such an arrangement of the shield is of low efficiency since heat is liberated in the shield by the alternating magnetic fields in immediate proximity to the superconductive winding. This circumstance calls for an additional consumption of the coolant, and the power needed to compensate for the heat thus produced may be quite considerable.
It is an object of the present invention to improve the efficiency of thermal insulation of a superconductive winding and, in consequence, to raise the efficiency of electrical apparatus including the winding.
According to the present invention there is provided cryogenically cooled electrical apparatus comprising a superconductive winding surrounded radially and axially by a heat shield a magnetic shield placed within the heat shield and cooled with the aid of a coolant circulating in ducts formed in the heat shield, the heat shield and the magnetic shield being arranged within an evacuated space between the winding and a housing of the electrical apparatus.
More specifically, the invention further provides a cryogenically cooled electrical machine comprising a superconductive field winding placed inside a hollow rotor and surrounded radially and axially by a heat shield, a magnetic shield arranged within the heat shield and cooled with the aid of a coolant circulating in ducts formed in the heat shield, the heat shield and the magnetic shield being arranged within an evacuated space between the rotor and a housing of the electrical machine.
Such an emliodiment of electrical machine allows the field winding to be protected from the effect of the heat produced in the magnetic shield and. consequently, the consumption of the coolant to be reduced and the efficiency of the electrical machine to be raised.
It is of advantage to make the heat shield of at least two coaxial cylinders, to arrange the magnetic shield between the cylinders and have it coupled rigidly there with. while the ducts for circulation of the cooling agent pass helically along the conjugated surfaces of the magnetic shield and the cylinders.
It is of further advantage for the electrical machine to be easier in manufacture, to couple the outer and inner surface of the magnetic shield rigidly with the heat shield by a threaded joint with gaps for circulation of the coolant.
It is also of advantage that the ducts for circulation of the coolant communicate with at least two flat annular inlet and outlet chambers arranged coaxially on the rotor and adjoining at least one of the end surfaces of the heat shield.
To step up the rate of flow of the coolant along the ducts, it is of further advantage to provide the flat annular chamber for the inlet of the coolant with a means for forcing the coolant into the ducts circulating the latter, and to provide the flat chamber for the outlet of the coolant with a means for sucking the coolant out of the ducts, thus creating a pressure drop of the circulating coolant.
For impactless circulation of the coolant and uniform cooling of the end surfaces of the flat annular chamber for the inlet of the coolant, the means for forcing the coolant into the ducts may be in the form of vanes fixed to the end surfaces of the flat annular chambers.
For impactless outlet of the coolant from the circulation ducts, the coolant sucking means may be made as a spirally wound strip fixed to the end surfaces of the annular chamber.
Other objects and advantages of the invention will become apparent from the following detailed description of preferred embodiments thereof, taken in conjunction with the accompanying drawings, wherein:
Figure 1 is a general longitudinal section view of a cryogenically cooled electrical machine in accordance with the present invention;
Figure 2 is an enlarged view of portion A of Figure 1 in accordance with the invention;
Figure 3 is a fragmentary sectional view of another embodiment of the magnetic and heat shields with flat annular chambers, in accordance with the invention;
Figure 4 is a cross-sectional view of the flat annular chamber for the inlet of the coolant. in accordance with the invention;
Figure 5 is a cross-sectional view of the flat annular chamber for the outlet of the coolant, in accordance with the invention.
The cryogenically cooled electrical machine comprises a hollow rotor 1 (Figure 1), whose shaft 2 rests in bearings 3 arranged within end shields 4 of a hermetically sealed shell 5, the inner surface whereof carries a stator winding 6. A vacuum required for thermal insulation of the rotor 1 is maintained in the space between the rotor 1 and the shell 5 of the electrical machine.
Proper sealing is ensured by rotating vacuum seals 7 provided within the end shields 4 of the machine.
The hollow rotor 1 comprises a nonmagnetic cylinder 8 containing a superconducting field winding 9. The field winding 9 is fixed in place with an epoxy compound and is made of a superconducting material, e.g., niobium stannate (Nb3Sn). It may also be made of other superconductive materials such as zirconium niobite or titanium niobite.
The space between the frame 5 and the non-magnetic cylinder 8 accommodates a heat shield of non-magnetic material, made in the form of two coaxial cylinders 10 and 11 with a magnetic shield 12 arranged therebetween. The magnetic shield 12 is made of a superconducting material, for instance, Nb3Sn, and a material of high electric conductivity, e.g., copper or aluminium. The superconducting material may be deposited on the surface of the electrically conducting material by sputtering. The magnetic shield 12 may also be made of fibres of a superconducting material, arranged within the electrically conducting material.
The field winding 9 is cooled to a superconducting state by a coolant 13 filling the non-magnetic cylinder 8. Liquid helium serves as the coolant.
To bring the coolant 13 up to the field winding 9, the shaft 2 of the rotor 1 is provided with an axial duct containing a pipe 14. Two flat annular chambers 15 adjoin the end surfaces of the heat shield for the inlet of the coolant 13, and two flat annular chambers 16 are arranged coaxially with the chambers 15 for the outlet of the coolant 13. The chambers 15 and 16 adjoining one end surface of the heat shield are defined by the end walls of the outer and inner coaxial cylinders 10 and 11, the heat shield and a hollow partition 17. The magnetic shield 12 has holes 18 made equidistant from the ends of the shield to return the coolant 13. The chambers 16 for the outlet of the coolant 13 communicate with ducts 19 provided in the shaft of the rotor 1 to expel the coolant 13. The magnetic shield 12 is cooled with the aid of the coolant drawn out of the non-magnetic cylinder 8. The coolant 13 circulate along ducts 20 (Figure 2) running helically along the conjugated surfaces of the magnetic shield 12 and cylinders 10, 11.
The ducts 20 for circulating the coolant 13 are essentially gaps formed in the threaded joint of the magnetic shield 12 and the outer and inner cylinders 10, 11 of the heat shield owing to the incomplete profile of the thread.
It is expedient that the thread be of the multiple-start type so as to enlarge the heat exchange surface. The ends of the the cylinders have L.H. and R.H. threads cut up to the holes 18.
Figure 3 shows another version of coupling of the magnetic shield and the outer and inner cylinders 23, 24 of the heat shield.
The magnetic shield 12 is in the form of a copper cylinder 22 with a superconducting layer of Nb3Sn deposited on its outer and inner surfaces. The cylinders 23, 24 and 22 are coupled through a heavy-drive fit. Ducts 25 for circulation of the coolant 13 run helically along the conjugated surfaces of the magnetic shield 12 and cylinders 23, 24, and are of a rectangular profile.
The flat annular chamber 15 for the inlet of the coolant 13 comprises centrifugal vanes 26 (Figure 4) fixed rigidly to the end surfaces of the chamber 15.
The flat annular chamber 16 for the outlet of the coolant 13 has a partition made of a strip 27 (Figure 5) spirally wound and fixed rigidly to the end surfaces of the chamber 16.
The liquid helium serving as the coolant 13 is supplied through the pipe 14 to the superconducting field winding 9. cools the latter and is then delivered to the chambers 15 arranged at both ends of the magnetic shield.
With the rotor 1 running, the evaporating helium enters the flat annular chambers 15, flows from the centre to the periphery and, in so doing, cools the walls of the chambers 15. As the rotor 1 rotates, the vanes 26 draw in the coolant 13 and impart to it a certain peripheral velocity. In consequence, the centrifugal forces acting upon the coolant 13 suck it additionally out of the non-magnetic cylinder 8 and force it into the ducts 20. The coolant 13 circulates further along the helically running ducts 20 made in the inner cylinder 11 of the head shield and is then supplied via the holes 18 into the ducts 20 made in the outer cylinder 10. On circulating along the helically running ducts 20, the coolant 13 retains the rotary component of its velocity and smoothly enters the flat annular chambers 16 where a strip 27 serves as a means for sucking the coolant 13 out of the ducts 20, thus creating a drop in the pressure of the circulating coolant 13. Then, the coolant 13 is delivered to the outlet ducts 19, cools the end walls of the chambers 16 and is expelled from the rotor of the machine.
Such an embodiment of the cryogenically cooled electrical machine makes it possible to remove the heat produced in the magnetic shield by the alternating magnetic fields.
Moreover. it raises the efficiency of thermal protection of the superconducting field winding by reducing the influx of heat from the ends of the electrical machine, this being ensured bv the provision of flat annular chambers at both ends of the machine.
WHAT WE CLAIM IS:
1. Cryogenically cooled electrical apparatus comprising a superconductive winding surrounded radiallv and axially by a heat shield, a magnetic shield placed within the heat shield and cooled with the aid of a coolant circulating in ducts formed in the
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (9)
1. Cryogenically cooled electrical apparatus comprising a superconductive winding surrounded radiallv and axially by a heat shield, a magnetic shield placed within the heat shield and cooled with the aid of a coolant circulating in ducts formed in the
heat shield, the heat shield and the magnetic shield being arranged within an evacuated space between the winding and a housing of the electrical apparatus.
2. A cryogenically cooled electrical machine comprising a superconductive field winding placed inside a hollow rotor and surrounded radially and axially by a heat shield, a magnetic shield arranged within the heat shield and cooled with the aid of a coolant circulating in ducts formed in the heat shield, the heat shield and the magnetic shield being arranged within an evacuated space between the rotor and a housing of the electrical machine.
3. An electrical machine according to claim 2 wherein the heat shield is made up of at least two coaxial cylinders, the magnetic shield is arranged between the cylinders and coupled rigidly there with, while the ducts for circulation of the coolant run helically along the conjugated surfaces of the magnetic shield and the cylinders.
4. An electrical machine according to claim 2, wherein the outer and inner surface of the magnetic shield is coupled rigidly with the heat shield by a threaded joint with gaps for circulation of the coolant.
5. An electrical machine according to claims 2. 3 and 4, wherein the ducts for circulation of the coolant communicate with at least two flat annular chambers for the inlet and outlet of the coolant, the chambers being arranged axially of the rotor and adjoining at least one of the end surfaces of the heat shield.
6. An electrical machine according to claim 5, wherein the flat chamber for the inlet of the coolant is provided with a means for forcing the coolant into the ducts for circulation of the coolant, while the chamber for the outlet of the coolant is provided with a means for sucking the coolant out of said ducts so as to create a pressure drop of the circulating coolant.
7. An electrical machine according to claim 6, wherein the means for forcing the coolant into the ducts for circulation of the coolant is in the form of vanes fixed to the end surfaces of the flat chamber.
8. An electrical machine according to claim 6, wherein the means for sucking the coolant out of the ducts for circulation of the coolant is a spirally wound strip fixed to the end surfaces of the flat chamber.
9. A cryogenically cooled electrical machine substantially as herein described with reference to the accompanying drawings.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB49253/77A GB1564646A (en) | 1976-11-30 | 1977-11-25 | Cryogenically cooled electrical apparatus |
| US05/855,778 US4174483A (en) | 1976-11-30 | 1977-11-29 | Cryogenically cooled electrical machine |
| FR7736155A FR2372539B1 (en) | 1976-11-30 | 1977-11-30 |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SU762421859A SU629601A1 (en) | 1976-11-30 | 1976-11-30 | Electric machine with cryogenic cooling |
| GB49253/77A GB1564646A (en) | 1976-11-30 | 1977-11-25 | Cryogenically cooled electrical apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1564646A true GB1564646A (en) | 1980-04-10 |
Family
ID=26266436
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB49253/77A Expired GB1564646A (en) | 1976-11-30 | 1977-11-25 | Cryogenically cooled electrical apparatus |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB1564646A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2547125A1 (en) * | 1983-05-31 | 1984-12-07 | Westinghouse Electric Corp | ANTI-RADIATION SHIELD WITH HELICAL PASSAGES FOR THE FLUID |
| DE10300269A1 (en) * | 2003-01-08 | 2004-07-22 | Siemens Ag | Electrical machine has non-magnetic outside of rotor envelope with electrical conductivity selected so magnetic fields generated by alternating voltage harmonics are absorbed |
| GB2414539A (en) * | 2004-05-25 | 2005-11-30 | Siemens Magnet Technology Ltd | An electrically conductive shield for a refrigerator |
-
1977
- 1977-11-25 GB GB49253/77A patent/GB1564646A/en not_active Expired
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2547125A1 (en) * | 1983-05-31 | 1984-12-07 | Westinghouse Electric Corp | ANTI-RADIATION SHIELD WITH HELICAL PASSAGES FOR THE FLUID |
| DE10300269A1 (en) * | 2003-01-08 | 2004-07-22 | Siemens Ag | Electrical machine has non-magnetic outside of rotor envelope with electrical conductivity selected so magnetic fields generated by alternating voltage harmonics are absorbed |
| GB2414539A (en) * | 2004-05-25 | 2005-11-30 | Siemens Magnet Technology Ltd | An electrically conductive shield for a refrigerator |
| GB2414539B (en) * | 2004-05-25 | 2007-07-25 | Siemens Magnet Technology Ltd | Electrically conductive shield for refrigerator |
| US8171741B2 (en) | 2004-05-25 | 2012-05-08 | Siemens Plc | Electrically conductive shield for refrigerator |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| PCNP | Patent ceased through non-payment of renewal fee |