CA1038052A - High voltage cable with synthetic insulation and a semiconducting layer - Google Patents
High voltage cable with synthetic insulation and a semiconducting layerInfo
- Publication number
- CA1038052A CA1038052A CA219,190A CA219190A CA1038052A CA 1038052 A CA1038052 A CA 1038052A CA 219190 A CA219190 A CA 219190A CA 1038052 A CA1038052 A CA 1038052A
- Authority
- CA
- Canada
- Prior art keywords
- layer
- semiconducting layer
- cable
- insulation
- per square
- 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
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B9/00—Power cables
- H01B9/02—Power cables with screens or conductive layers, e.g. for avoiding large potential gradients
- H01B9/027—Power cables with screens or conductive layers, e.g. for avoiding large potential gradients composed of semi-conducting layers
Landscapes
- Insulated Conductors (AREA)
- Conductive Materials (AREA)
- Communication Cables (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An electrical high voltage cable is disclosed which comprises a conductor, an inner semiconducting layer, an insulation layer and an outer semiconducting layer beneath a metallic screen and a covering cable sheath. The outer semiconducting layer has a resistance measured along its outer surface that exceeds a value of 106 ohms per square and the layer has good adherence to the underlying insulation. The arrangement of the outer semiconducting layer obviates dangerous voltage gradients in the insulation layer of the cable.
An electrical high voltage cable is disclosed which comprises a conductor, an inner semiconducting layer, an insulation layer and an outer semiconducting layer beneath a metallic screen and a covering cable sheath. The outer semiconducting layer has a resistance measured along its outer surface that exceeds a value of 106 ohms per square and the layer has good adherence to the underlying insulation. The arrangement of the outer semiconducting layer obviates dangerous voltage gradients in the insulation layer of the cable.
Description
:
The present invention relates to a high voltage cable insulated with synthetic insulation around which a semiconduct-ing layer is applied, and more specifically to a high voltage cable in which the semiconducting layer has a predetermined specific conductance.
In a typical high voltage cable, an inner semiconducting tape or layer is wrapped or extruded around a metal conductor and a layer of insulation is then extruded over the inner layer.
An earth screening or grounding element is thereafter applied concentrically over the insulation, which element usually con-sists of a semiconducting layer and a metallic earth or ground return screen, whereby a uni~orm e~uipotential surEace around the insulation is createcl. ~ stud~ O:e the c~lrrent proportions in the layer shows that the outer semiconducting layer conducts a capacitive current across the layer in a radial direc-tion from the conductor to the surrounding screen. Furthermore, a resis-tive current appears in the layer and equalizes the voltages which, due to an eventual non-uniform field distribution, appear in a peripheral direction. The surrounding cable sheath can be applied on the metallic screen nearest the outer semiconducting layer.
In synthetic cables, i.e. cables having some form of extruded plastic or rubber insulation, the inner semiconductor is usually applied in the same operation as the insulation. It has been found preferable to also apply the outer semiconductor in the same operation, a so-called triple extrusion. The semi-conducting layer and the insulation material then adhere well together and provide a mechanically and electrically reliable product. Triple extrusion has primarily been used on cables ~or high voltage applications and moreover when specially trained installation personnel are used.
One problem associated with known high voltage cables - 1 - ,~
~(~8~S2 relates to reliable cable preparation at an assembling works.
The preparation re~uires that parts of the cable sheath or jacket be removed together with the screening layers and the insulation in order to reach the conductor. In some known cable construct ons it is re~uired, in order to facilitate the prepara-tion of the cable, to manufact-ure the outer semiconductor in the form of tapes which are directly applied on the insulation or as layers painted or sprayed outside the insulation Eollowed by semiconducting tapes wrapped around the painted layers. It is also known in the art to extrude around the insulation a "t~re"
or sleeve of semiconducting rubber, for example, which tightens around the insulation. A ~rincipal disadvantage with the ore-going known methods is that a corona discharge can arise in the air slots or spaces which are created at the overlap portion o~
the semiconducting tapes. ~lso, clearances can arise between a loosely applied semiconducting layer and the insulation at points of mechanical and thermal stress. Furthermore, the semiconduct-ing paint can he difficult to remove, especially if it has burnt or bonded firmly onto the layer underneath in the event of an overheating condition.
At the ends of the cable, where the semiconductor has to ; be removed a predetermined length from the connection point, high longitudinal field strengths appear at the thus created screen edge. It is known to decrease the Eield strength at an abruptly terminated screen by arranging layers having a prede-termined ~ ~ resistancehout~side the insulation, which lavers extend Erom the screen edge to the conductor. ~ccordingly, a part of a leading earth or ground return current of the cable will flow through the resistive layer which creates a dispersed potential rise that decreases the field strength and prevents corona discharge.
` ~0380SZ
Other field strength equalizing methods are also known.
The methods used require special material or special accessories, a skilful assemble~ and time consuming work. Especially troublesome is the removal of substantially all traces of the semiconducting layer, particularly when it adheres well to the insulating surface. Manufacturers therefore endeavour to make semiconducting layers which can be simply separated from the insulation surface without leaving portions thereon.
However, the easier it is to strip away the semiconductor, the greater is the risk for damage occurring at points of stress.
The object of the present invention is to provide a cable having one or more cable cores, each of which includes an outer semiconducting layer having good electrical and mechanical stability which substantially eliminates the foregolng inconveniences and problems when terminating the aable.
Accordingly, the invention provides an electrical cable, including a conductor and a surrounding insulation of synthetic material together with an outer layer of semiconducting material disposed in good adherence on the surface of the insulation and extending substantially along the whole length of the cable, the outer semiconducting layer being formed of synthetic material having a resistance at the surface thereof that is substantially voltage independent and which exce~ds a value of 106 ohms per square.
The invention will now be more particularly described with reference to an embodiment thereof shown, bv way of example, in the accompanying drawings in which:
Fig. 1 is a plan view of an end portion o~ a cable according to the present invention; and Fig. 2 is a side view, partly in section, of a cable end portion according to the present invention together with a graph showing a voltage gradient thereat.
~ -3-The description of the invention as follows covers a single core cable but is applicable to a separate core of a multiple core cable.
In the cable according to Figure 1 an inner conductor 1 comprises a plurality of twisted and packed wires. Around the conductor 1 an inner semiconducting layer 2 is applied in the form of semiconducting tapes or extruded semiconducting material to equalize any ~oltage stresses from the lndividual wires of - 3~
~P, SZ
the conductor 1. A layer o insulation 3 is provided which consists of, for example, polyethylene material having a thick-ness that is determined by the rated voltage of the cable and is applied around the layer 20 Outside the insulation 3 an outer semiconducting layer 4 is applied, usually by extruding and subsequent vulcanizat.ion.
In known cables, the resistance, of the outer semi-conducting layer, measured longitudinally along the outer surface of the cable core, is low and at most about 106 ohms per square.
Thus, a field pattern in the cable is obtained wh.ich shows small voltage gradients occurring in a tangential direction at frequencies higher than the power frequency, for example, during transient e~ents such as lightning discharges ancl the like.
Calculations show, however, that the resistance of the layer can be increased to considerably more than the usual values oE 102 _ 104 ohms per square, commonly used in practice while maintaining rellability of service. According to the invention, a value greater than 106 ohms per square, is chosen, for example, 107 ohms per square. Accordingly, the advantages of the layer 4 as a field equali2ing device is essentially maintained and certain further advantages will be atained at terminal ends of the cable as will be apparent from the description in connec~ion with Figure 2.
The semiconducting layer 4 having a resistance of high value may consist of polyethylene material doped with admixtures of carbon, for example carbon black, to obtain the desired specific resistance value. The layer is then applied suitably by extrusion or preferably by triple extrusion which gives the best electrical and mechanical stability. It is also possible to apply the outer semiconductor layer ~ by means of continuous lacquering with a lacquer having a high resistance in principally the same manner as it is applied on layers having low values o ~La3~QSZ
resis~ance. For example, the layer can be applied by spraying, dipping or by electrostatic painting. In this way a good adherence to the underlying insulation layer can be attained.
The extruded outer semiconductor 4 according to the invention can be an elastomer, thermoplastic or cross-linked plastic, (vulcanized) which, in the manufacturing process, can be made to completely adhere to the insulation surface so as to virtually eliminate the possibility of corona discharge. In certain cases the semiconducting layer 4 can be covered with an applied layer 5 of conducting plastic, textile, synthetic fibre or the like having a resistance per square value of conventional magnitude.
In this event, the object of the invention has not been abandoned, as this outer material can be simply removed when preparincJ a cable termination.
In Figure 2 the volt~ge dlstribution along a cable termination is shown in a graph to illustrate the advantage of the invention. The cable termination is shown in a longitudinal section and as in Figure 1 there is shown an inner conductor 1, on which the inner semiconducting layer 2 is applied. The outer semiconducting layer 4 is disposed on the insulation 3 and in order to discharge any field currents to earth an earthed metallic screen 6, fabricated of copper wire, is applied in a known manner. The screen 6 is surrounded by a cable sheath 7.
Beneath the screen 6 there is provided an extra semiconducting layer 5. In the graph, the potential of the conductor is de-signated~ro, for example 1?/ ~ or 24/ ~ kV, the screen 6 having the potential 0. ~t the termination of the cable, -the earthed screen 6 is removed together with the semiconducting layer 5 so that an end portion of length R of the outer semiconducting layer 4 is uncovered. Furthermore, part of the inner semi-conducting layer 2 and the insulation 3 has been removed, 1)5i2 so that the conductor l is uncovered at the very end of the cable.
Th~ outer semiconducting layer 4 is brought into electrical contact with the conductor at the free end of the cable, for example, by applying some layers of semiconducting tape 8.
Of interest is a voltage distribution which arises in the outer semiconducting layer 4 along the portion Q between the screen 6 and the inner conductor 1. At too high a voltage gradient, an undesirable corona discharge arises in voltage tests which are prescribed by standard references. The discharge will occur at the screen edge of conventionally fabricated cables, i.e. the edge which is formed when the insulation of the cable i9 uncovered ~rom a conducting surface covering if no special measures are taken. With a cable construction according to the present invention this surface covering, i.e. the outer seml-conducting layer 4 is not removed, but 1~ mainta~ned and Eulfills its function to equalize the longitudinal field between the outer screen 6 and the inner conductor 1. From the graph of Fig. 2 it appears that by means of a semiconducting layer, the resistance per square of which has been chosen according to the idea of the invention, an even voltage distribution along the uncovered cable path having the length Q is obtained. The wave forms in the diagram are shown for different values of resistance per square ~ for the outer semiconducting layer 4, and for a predetermined value ~ = lO ohms per square an approximately linear voltage distribution can be obtained. With a layer o~ lower resistance, i.e. about the value range lO2 - 104 ohms per square, too great a power is developed in the semiconducting layer which could cause a fire. As a precaution it should be noted that concen-trated creeping current paths and surface flash-over will arise as a consequence of the semiconducting layer 4 being completely homogeneous in its resistance per square.
The present invention relates to a high voltage cable insulated with synthetic insulation around which a semiconduct-ing layer is applied, and more specifically to a high voltage cable in which the semiconducting layer has a predetermined specific conductance.
In a typical high voltage cable, an inner semiconducting tape or layer is wrapped or extruded around a metal conductor and a layer of insulation is then extruded over the inner layer.
An earth screening or grounding element is thereafter applied concentrically over the insulation, which element usually con-sists of a semiconducting layer and a metallic earth or ground return screen, whereby a uni~orm e~uipotential surEace around the insulation is createcl. ~ stud~ O:e the c~lrrent proportions in the layer shows that the outer semiconducting layer conducts a capacitive current across the layer in a radial direc-tion from the conductor to the surrounding screen. Furthermore, a resis-tive current appears in the layer and equalizes the voltages which, due to an eventual non-uniform field distribution, appear in a peripheral direction. The surrounding cable sheath can be applied on the metallic screen nearest the outer semiconducting layer.
In synthetic cables, i.e. cables having some form of extruded plastic or rubber insulation, the inner semiconductor is usually applied in the same operation as the insulation. It has been found preferable to also apply the outer semiconductor in the same operation, a so-called triple extrusion. The semi-conducting layer and the insulation material then adhere well together and provide a mechanically and electrically reliable product. Triple extrusion has primarily been used on cables ~or high voltage applications and moreover when specially trained installation personnel are used.
One problem associated with known high voltage cables - 1 - ,~
~(~8~S2 relates to reliable cable preparation at an assembling works.
The preparation re~uires that parts of the cable sheath or jacket be removed together with the screening layers and the insulation in order to reach the conductor. In some known cable construct ons it is re~uired, in order to facilitate the prepara-tion of the cable, to manufact-ure the outer semiconductor in the form of tapes which are directly applied on the insulation or as layers painted or sprayed outside the insulation Eollowed by semiconducting tapes wrapped around the painted layers. It is also known in the art to extrude around the insulation a "t~re"
or sleeve of semiconducting rubber, for example, which tightens around the insulation. A ~rincipal disadvantage with the ore-going known methods is that a corona discharge can arise in the air slots or spaces which are created at the overlap portion o~
the semiconducting tapes. ~lso, clearances can arise between a loosely applied semiconducting layer and the insulation at points of mechanical and thermal stress. Furthermore, the semiconduct-ing paint can he difficult to remove, especially if it has burnt or bonded firmly onto the layer underneath in the event of an overheating condition.
At the ends of the cable, where the semiconductor has to ; be removed a predetermined length from the connection point, high longitudinal field strengths appear at the thus created screen edge. It is known to decrease the Eield strength at an abruptly terminated screen by arranging layers having a prede-termined ~ ~ resistancehout~side the insulation, which lavers extend Erom the screen edge to the conductor. ~ccordingly, a part of a leading earth or ground return current of the cable will flow through the resistive layer which creates a dispersed potential rise that decreases the field strength and prevents corona discharge.
` ~0380SZ
Other field strength equalizing methods are also known.
The methods used require special material or special accessories, a skilful assemble~ and time consuming work. Especially troublesome is the removal of substantially all traces of the semiconducting layer, particularly when it adheres well to the insulating surface. Manufacturers therefore endeavour to make semiconducting layers which can be simply separated from the insulation surface without leaving portions thereon.
However, the easier it is to strip away the semiconductor, the greater is the risk for damage occurring at points of stress.
The object of the present invention is to provide a cable having one or more cable cores, each of which includes an outer semiconducting layer having good electrical and mechanical stability which substantially eliminates the foregolng inconveniences and problems when terminating the aable.
Accordingly, the invention provides an electrical cable, including a conductor and a surrounding insulation of synthetic material together with an outer layer of semiconducting material disposed in good adherence on the surface of the insulation and extending substantially along the whole length of the cable, the outer semiconducting layer being formed of synthetic material having a resistance at the surface thereof that is substantially voltage independent and which exce~ds a value of 106 ohms per square.
The invention will now be more particularly described with reference to an embodiment thereof shown, bv way of example, in the accompanying drawings in which:
Fig. 1 is a plan view of an end portion o~ a cable according to the present invention; and Fig. 2 is a side view, partly in section, of a cable end portion according to the present invention together with a graph showing a voltage gradient thereat.
~ -3-The description of the invention as follows covers a single core cable but is applicable to a separate core of a multiple core cable.
In the cable according to Figure 1 an inner conductor 1 comprises a plurality of twisted and packed wires. Around the conductor 1 an inner semiconducting layer 2 is applied in the form of semiconducting tapes or extruded semiconducting material to equalize any ~oltage stresses from the lndividual wires of - 3~
~P, SZ
the conductor 1. A layer o insulation 3 is provided which consists of, for example, polyethylene material having a thick-ness that is determined by the rated voltage of the cable and is applied around the layer 20 Outside the insulation 3 an outer semiconducting layer 4 is applied, usually by extruding and subsequent vulcanizat.ion.
In known cables, the resistance, of the outer semi-conducting layer, measured longitudinally along the outer surface of the cable core, is low and at most about 106 ohms per square.
Thus, a field pattern in the cable is obtained wh.ich shows small voltage gradients occurring in a tangential direction at frequencies higher than the power frequency, for example, during transient e~ents such as lightning discharges ancl the like.
Calculations show, however, that the resistance of the layer can be increased to considerably more than the usual values oE 102 _ 104 ohms per square, commonly used in practice while maintaining rellability of service. According to the invention, a value greater than 106 ohms per square, is chosen, for example, 107 ohms per square. Accordingly, the advantages of the layer 4 as a field equali2ing device is essentially maintained and certain further advantages will be atained at terminal ends of the cable as will be apparent from the description in connec~ion with Figure 2.
The semiconducting layer 4 having a resistance of high value may consist of polyethylene material doped with admixtures of carbon, for example carbon black, to obtain the desired specific resistance value. The layer is then applied suitably by extrusion or preferably by triple extrusion which gives the best electrical and mechanical stability. It is also possible to apply the outer semiconductor layer ~ by means of continuous lacquering with a lacquer having a high resistance in principally the same manner as it is applied on layers having low values o ~La3~QSZ
resis~ance. For example, the layer can be applied by spraying, dipping or by electrostatic painting. In this way a good adherence to the underlying insulation layer can be attained.
The extruded outer semiconductor 4 according to the invention can be an elastomer, thermoplastic or cross-linked plastic, (vulcanized) which, in the manufacturing process, can be made to completely adhere to the insulation surface so as to virtually eliminate the possibility of corona discharge. In certain cases the semiconducting layer 4 can be covered with an applied layer 5 of conducting plastic, textile, synthetic fibre or the like having a resistance per square value of conventional magnitude.
In this event, the object of the invention has not been abandoned, as this outer material can be simply removed when preparincJ a cable termination.
In Figure 2 the volt~ge dlstribution along a cable termination is shown in a graph to illustrate the advantage of the invention. The cable termination is shown in a longitudinal section and as in Figure 1 there is shown an inner conductor 1, on which the inner semiconducting layer 2 is applied. The outer semiconducting layer 4 is disposed on the insulation 3 and in order to discharge any field currents to earth an earthed metallic screen 6, fabricated of copper wire, is applied in a known manner. The screen 6 is surrounded by a cable sheath 7.
Beneath the screen 6 there is provided an extra semiconducting layer 5. In the graph, the potential of the conductor is de-signated~ro, for example 1?/ ~ or 24/ ~ kV, the screen 6 having the potential 0. ~t the termination of the cable, -the earthed screen 6 is removed together with the semiconducting layer 5 so that an end portion of length R of the outer semiconducting layer 4 is uncovered. Furthermore, part of the inner semi-conducting layer 2 and the insulation 3 has been removed, 1)5i2 so that the conductor l is uncovered at the very end of the cable.
Th~ outer semiconducting layer 4 is brought into electrical contact with the conductor at the free end of the cable, for example, by applying some layers of semiconducting tape 8.
Of interest is a voltage distribution which arises in the outer semiconducting layer 4 along the portion Q between the screen 6 and the inner conductor 1. At too high a voltage gradient, an undesirable corona discharge arises in voltage tests which are prescribed by standard references. The discharge will occur at the screen edge of conventionally fabricated cables, i.e. the edge which is formed when the insulation of the cable i9 uncovered ~rom a conducting surface covering if no special measures are taken. With a cable construction according to the present invention this surface covering, i.e. the outer seml-conducting layer 4 is not removed, but 1~ mainta~ned and Eulfills its function to equalize the longitudinal field between the outer screen 6 and the inner conductor 1. From the graph of Fig. 2 it appears that by means of a semiconducting layer, the resistance per square of which has been chosen according to the idea of the invention, an even voltage distribution along the uncovered cable path having the length Q is obtained. The wave forms in the diagram are shown for different values of resistance per square ~ for the outer semiconducting layer 4, and for a predetermined value ~ = lO ohms per square an approximately linear voltage distribution can be obtained. With a layer o~ lower resistance, i.e. about the value range lO2 - 104 ohms per square, too great a power is developed in the semiconducting layer which could cause a fire. As a precaution it should be noted that concen-trated creeping current paths and surface flash-over will arise as a consequence of the semiconducting layer 4 being completely homogeneous in its resistance per square.
Claims (7)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An electrical cable, including a conductor and a surrounding insulation of synthetic material together with a outer layer of semiconducting material disposed in strong adherence on the surface of the insulation and extending substantially along the whole length of the cable, the outer semiconducting layer being formed of synthetic material having a resistance at the surface thereof that is substantially voltage independent and which exceeds a value of 106 ohms per square.
2. A cable according to claim 1, wherein the material of the outer semiconducting layer has been doped with a predetermined conducting material, including carbon, in order to obtain a predetermined resistance per square.
3. A cable according to claim 1 or 2, wherein the outer semiconducting layer has a resistance at the surface thereof not exceeding 1011 ohms per square.
4. A cable according to claim 1 or 2 wherein the outer semi-conducting layer has a resistance at the surface there-of in the range of 107 - 109 ohms per square.
5. A cable according to claim 1, including a further semiconducting layer comprising one of paper, textile and synthetic material, disposed around said outer semiconducting layer in easily removable contact, said further layer having a resistance at the outer surface thereof not exceeding 106 ohms per square.
6. A cable according to claim 1, wherein the outer semiconducting layer is coextensive with the surface of the insulation.
7. A cable according to claim 1, wherein the outer semiconducting layer is lacquer that has been continuously applied via one of spraying, dipping and electrostatic painting.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE7401244A SE384420B (en) | 1974-01-31 | 1974-01-31 | ELECTRICAL CABLE WITH SYNTHETIC INSULATION AND AN OUTER SEMICONDUCTIVE LAYER |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1038052A true CA1038052A (en) | 1978-09-05 |
Family
ID=20320066
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA219,190A Expired CA1038052A (en) | 1974-01-31 | 1975-01-31 | High voltage cable with synthetic insulation and a semiconducting layer |
Country Status (15)
| Country | Link |
|---|---|
| JP (1) | JPS50109479A (en) |
| AR (1) | AR211382Q (en) |
| BE (1) | BE825068A (en) |
| BR (1) | BR7500229A (en) |
| CA (1) | CA1038052A (en) |
| CH (1) | CH587545A5 (en) |
| DE (1) | DE2501811A1 (en) |
| DK (1) | DK32675A (en) |
| FI (1) | FI68477C (en) |
| FR (1) | FR2260173B1 (en) |
| GB (1) | GB1493163A (en) |
| IT (1) | IT1031252B (en) |
| NL (1) | NL7501168A (en) |
| NO (1) | NO750313L (en) |
| SE (1) | SE384420B (en) |
Families Citing this family (24)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB8303462D0 (en) * | 1983-02-08 | 1983-03-16 | Raychem Gmbh | Electrical stress control |
| DE3533509A1 (en) * | 1985-09-20 | 1987-04-02 | Kabelmetal Electro Gmbh | Cable end seal for electrical high-voltage cables |
| GB9012062D0 (en) * | 1990-05-30 | 1990-07-18 | Phillips Cables Ltd | Moisture-impermeable stranded electric conductor |
| ATE250817T1 (en) | 1996-05-29 | 2003-10-15 | Abb Ab | CONDUCTOR FOR HIGH VOLTAGE WINDINGS AND ROTATING ELECTRICAL MACHINE HAVING SUCH A CONDUCTOR |
| SE9602079D0 (en) | 1996-05-29 | 1996-05-29 | Asea Brown Boveri | Rotating electric machines with magnetic circuit for high voltage and a method for manufacturing the same |
| SE510192C2 (en) | 1996-05-29 | 1999-04-26 | Asea Brown Boveri | Procedure and switching arrangements to reduce problems with three-tier currents that may occur in alternator and motor operation of AC machines connected to three-phase distribution or transmission networks |
| EP1016185A1 (en) | 1996-05-29 | 2000-07-05 | Abb Ab | Insulated conductor for high-voltage windings and a method of manufacturing the same |
| PL330234A1 (en) | 1996-05-29 | 1999-05-10 | Asea Brown Boveri | Electromagnetic device |
| SE512917C2 (en) | 1996-11-04 | 2000-06-05 | Abb Ab | Method, apparatus and cable guide for winding an electric machine |
| SE509072C2 (en) | 1996-11-04 | 1998-11-30 | Asea Brown Boveri | Anode, anodizing process, anodized wire and use of such wire in an electrical device |
| SE515843C2 (en) | 1996-11-04 | 2001-10-15 | Abb Ab | Axial cooling of rotor |
| SE510422C2 (en) | 1996-11-04 | 1999-05-25 | Asea Brown Boveri | Magnetic sheet metal core for electric machines |
| SE9704423D0 (en) | 1997-02-03 | 1997-11-28 | Asea Brown Boveri | Rotary electric machine with flushing support |
| SE9704422D0 (en) | 1997-02-03 | 1997-11-28 | Asea Brown Boveri | End plate |
| SE9704427D0 (en) | 1997-02-03 | 1997-11-28 | Asea Brown Boveri | Fastening device for electric rotary machines |
| SE508544C2 (en) | 1997-02-03 | 1998-10-12 | Asea Brown Boveri | Method and apparatus for mounting a stator winding consisting of a cable. |
| SE9704421D0 (en) | 1997-02-03 | 1997-11-28 | Asea Brown Boveri | Series compensation of electric alternator |
| SE508543C2 (en) | 1997-02-03 | 1998-10-12 | Asea Brown Boveri | Coiling |
| SE9704431D0 (en) | 1997-02-03 | 1997-11-28 | Asea Brown Boveri | Power control of synchronous machine |
| GB2331867A (en) | 1997-11-28 | 1999-06-02 | Asea Brown Boveri | Power cable termination |
| AU9362998A (en) | 1997-11-28 | 1999-06-16 | Asea Brown Boveri Ab | Method and device for controlling the magnetic flux with an auxiliary winding ina rotating high voltage electric alternating current machine |
| GB2332559A (en) * | 1997-11-28 | 1999-06-23 | Asea Brown Boveri | An insulated conductor |
| US6801421B1 (en) | 1998-09-29 | 2004-10-05 | Abb Ab | Switchable flux control for high power static electromagnetic devices |
| DE102015216276B4 (en) | 2015-08-26 | 2022-06-15 | Jolanta SWIATOWSKA | Single core cable with a seal against moisture ingress and a return core |
-
1974
- 1974-01-31 SE SE7401244A patent/SE384420B/en not_active IP Right Cessation
-
1975
- 1975-01-14 BR BR229/75A patent/BR7500229A/en unknown
- 1975-01-17 DE DE19752501811 patent/DE2501811A1/en active Pending
- 1975-01-28 FR FR7502568A patent/FR2260173B1/fr not_active Expired
- 1975-01-28 GB GB3755/75A patent/GB1493163A/en not_active Expired
- 1975-01-28 FI FI750213A patent/FI68477C/en not_active IP Right Cessation
- 1975-01-29 IT IT19707/75A patent/IT1031252B/en active
- 1975-01-30 AR AR257464A patent/AR211382Q/en unknown
- 1975-01-30 JP JP50012947A patent/JPS50109479A/ja active Pending
- 1975-01-30 DK DK32675*#A patent/DK32675A/da not_active Application Discontinuation
- 1975-01-30 CH CH112075A patent/CH587545A5/xx not_active IP Right Cessation
- 1975-01-31 NO NO750313A patent/NO750313L/no unknown
- 1975-01-31 NL NL7501168A patent/NL7501168A/en not_active Application Discontinuation
- 1975-01-31 BE BE152956A patent/BE825068A/en not_active IP Right Cessation
- 1975-01-31 CA CA219,190A patent/CA1038052A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| AR211382Q (en) | 1977-12-15 |
| FR2260173B1 (en) | 1979-09-28 |
| JPS50109479A (en) | 1975-08-28 |
| DE2501811A1 (en) | 1975-08-14 |
| SE384420B (en) | 1976-05-03 |
| NL7501168A (en) | 1975-08-04 |
| FI68477C (en) | 1985-09-10 |
| SE7401244L (en) | 1975-08-01 |
| CH587545A5 (en) | 1977-05-13 |
| FI68477B (en) | 1985-05-31 |
| FI750213A (en) | 1975-08-01 |
| BR7500229A (en) | 1975-11-04 |
| BE825068A (en) | 1975-05-15 |
| AU7707175A (en) | 1976-07-08 |
| GB1493163A (en) | 1977-11-23 |
| NO750313L (en) | 1975-08-25 |
| IT1031252B (en) | 1979-04-30 |
| FR2260173A1 (en) | 1975-08-29 |
| DK32675A (en) | 1975-09-29 |
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