EP2232677A2 - Barre de stator pour une machine électrique, et machine électrique comprenant ladite barre de stator - Google Patents

Barre de stator pour une machine électrique, et machine électrique comprenant ladite barre de stator

Info

Publication number
EP2232677A2
EP2232677A2 EP07866839A EP07866839A EP2232677A2 EP 2232677 A2 EP2232677 A2 EP 2232677A2 EP 07866839 A EP07866839 A EP 07866839A EP 07866839 A EP07866839 A EP 07866839A EP 2232677 A2 EP2232677 A2 EP 2232677A2
Authority
EP
European Patent Office
Prior art keywords
main body
bar according
lamina
bar
along
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.)
Withdrawn
Application number
EP07866839A
Other languages
German (de)
English (en)
Inventor
Rodolfo Exner
Alessandro Oldrati
Giorgio Vercelli
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ansaldo Energia SpA
Original Assignee
Ansaldo Energia SpA
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Ansaldo Energia SpA filed Critical Ansaldo Energia SpA
Publication of EP2232677A2 publication Critical patent/EP2232677A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/04—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors
    • H02K3/12—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors arranged in slots
    • H02K3/14—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors arranged in slots with transposed conductors, e.g. twisted conductors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/32—Windings characterised by the shape, form or construction of the insulation
    • H02K3/34—Windings characterised by the shape, form or construction of the insulation between conductors or between conductor and core, e.g. slot insulation
    • H02K3/345—Windings characterised by the shape, form or construction of the insulation between conductors or between conductor and core, e.g. slot insulation between conductor and core, e.g. slot insulation
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/32—Windings characterised by the shape, form or construction of the insulation
    • H02K3/40—Windings characterised by the shape, form or construction of the insulation for high voltage, e.g. affording protection against corona discharges

Definitions

  • the present invention relates to a stator bar of an electrical machine and to an electrical machine comprising said bar.
  • the present invention regards a stator bar of an alternator and an alternator .
  • a known type of alternator comprises a rotor, extending along a longitudinal axis, and a stator, which is substantially- shaped like a hollow cylinder coaxial to the rotor, which extends around the rotor.
  • the stator basically comprises a cylindrical ferromagnetic core having a plurality of axial slots, two opposed ends, and a plurality of stator bars, each of which is set along a path partly within a respective axial slot and partly defined at the ends, and is coated with a layer of insulating material .
  • Each stator bar comprises a main body defined by a plurality of elongated conductive elements, generally made of copper and coated with insulating material, which are substantially parallel and stacked on columns set alongside one another.
  • each elongated conductive element extends along a path having a plurality of transpositions from one column to the other so as to generate a sort of intertwining between the elongated conductive elements of the main body.
  • the geometrical discontinuity generated by the transpositions creates a situation of deformation of the electrical field, which, if not appropriately attenuated, gives rise to phenomena of dissipation of energy.
  • the transpositions generate in the main body empty spaces full of air, which are responsible for dissipative phenomena, such as partial discharges and the corona effect.
  • a conductive or insulating putty is normally used for filling the empty spaces generated by the transpositions. This solution, however, presents some drawbacks .
  • the putty in fact, is applied in standard environmental conditions, and consequently it frequently occurs that air bubbles are formed within the main body, or even that said bubbles are englobed in the putty, giving rise to small vacuoles full of air.
  • the air bubbles in the bar and the vacuoles in the putty increase the risk of occurrence of dissipative phenomena, in particular partial discharges, which impair the integrity of the bars (putty and various insulating coatings) , thus jeopardizing the service life of the alternator.
  • one aim of the present invention is to provide a stator bar that will be free from the drawbacks of the known art referred to above,- in particular, one aim of the invention is to provide a stator bar that will attenuate the dissipative phenomena presented by the stator bars of the known art, and, at the same time, will be easy and economically advantageous to produce.
  • the present invention relates to a stator bar for an electrical machine comprising two opposed ends, the bar comprising a main body defined by: a plurality of substantially parallel elongated conductive elements stacked on columns set alongside one another, each of which extends along a path having a plurality of transpositions from one column to another; and a filling element adapted for filling empty spaces of the main body generated by the transpositions,- the stator bar is characterized in that it comprises at least one lamina made of conductive material - -
  • a further aim of the invention is to provide an electrical machine that will be reliable and efficient.
  • the present invention relates to an electrical machine comprising a rotor, extending along a longitudinal axis, and a stator, which has a hollow cylindrical shape coaxial to the rotor and extending around the rotor, the stator comprising a cylindrical core having a plurality of axial slots, two opposed ends, and a plurality of stator bars, each of which is set in a respective slot and is of the type specified in any one of Claims 1 to 16.
  • FIG. 1 is a schematic view in longitudinal cross section of an electrical machine according to the present invention.
  • FIG. 2 is a cross-sectional view of the stator bar according to the present invention
  • - Figure 3 is a perspective view, with parts in cross section and parts removed for reasons of clarity, of the stator bar of Figure 1 ;
  • FIG. 4 is a longitudinal view, with parts removed for reasons of clarity, of the stator bar of Figure 1.
  • an alternator which extends along a longitudinal axis A and comprises a rotor 2, which is the mobile coil, and a stator 3, which is the fixed armature of the alternator 1.
  • the rotor 2 has a substantially cylindrical shape and turns, moved by a turbine (not illustrated) , about its own axis, which coincides with the longitudinal axis A of the alternator 1.
  • the stator 3 substantially has the form of a hollow cylinder coaxial to the rotor 2 , extends around the rotor 2 , and is separated from the rotor 2 by a gap.
  • the stator 3 comprises a cylindrical ferromagnetic core 4 having a plurality of axial slots 5, a plurality of stator bars 6, each of which is traversed by an induced current, and two opposed ends 7.
  • Each stator bar 6 extends along a first section 8, substantially parallel to the axis A and inside a respective axial slot 5 of the core 4, and along two second sections 9 at the ends 7.
  • the second sections 9 of the stator bars 6 are indicated collectively with two annular windings set at the ends 7.
  • the dashed lines indicate the area of separation between the first section 8 of the stator bar 6, inside the respective axial slot 5, and the second sections 9 of the stator bar 6, set at the ends 7.
  • each stator bar 6 comprises a main body 10, an insulating coating 11, a lamina 12 made of conductive material, an insulating coating 13, and a conductive coating 14.
  • the main body 10 substantially has a rectangular cross section and comprises a plurality of substantially parallel elongated conductive elements 15, stacked on two columns 16 set alongside one another, and a filling element 18.
  • Each elongated conductive element 15 is made of copper and is coated with a layer of insulating material (not illustrated for reasons of simplicity in the attached figures) .
  • each elongated conductive element 15 extends along a path having a plurality of rectilinear sections 19 and a plurality of transpositions 20 from one column 16 to the other.
  • the transpositions 20 are present only along the first section 8 of the stator bar
  • each stator bar 6 comprises a plurality of fixing elements (not illustrated for reasons of simplicity in the attached figures) , which are adapted to guarantee the connection between the columns 16 and between the elongated conductive
  • Said fixing elements are preferably made of a material comprising a strip of glass-fibre and epoxy-resin fabric and are appropriately assembled.
  • the filling element 18 is an insulating putty.
  • the filling L5 element 18 is adapted for filling the empty spaces in the main body 10 principally generated by the transpositions 20.
  • the main body 10 moreover comprises sheets 22 made of insulating material, for example
  • the lamina 12 made of conductive material is provided with one end 24 electrically connected to an elongated conductive element 15 of the main 50 body 10 and extends along a substantially rectilinear side of the main body 10.
  • the lamina 12 extends parallel to the main body 10 and only along the first section 8 of the stator bar 6, 35 i.e., only in the section in which the transpositions 20 of the elongated conductive elements 15 are present.
  • the end 24 of the lamina 12 is welded to an elongated conductive element 15 substantially at the centre C of one of the transpositions 20
  • said elongated conductive element 15 set in the proximity of one of the ends 7 of the alternator 1.
  • said elongated conductive element 15 is without the layer of insulating material (not illustrated in the attached figures), which envelops each elongated conductive element 15.
  • the lamina 12 is made of metal material, preferably copper.
  • the lamina 12 provides the so-called internal corona protection of the stator bar 6.
  • the insulating coating 11 substantially coats the main body 10 throughout the section 8 of the stator bar 6 inside the core 4, except for an area 23 ( Figure 4) , which extends around the centre C of the stator bar 6 inside the core 4, except for an area 23 ( Figure 4) , which extends around the centre C of the stator bar 6 inside the core 4, except for an area 23 ( Figure 4) , which extends around the centre C of the stator bar 6 inside the core 4, except for an area 23 ( Figure 4) , which extends around the centre C of the
  • the insulating coating 11 is obtained by means of an insulating tape, wrapped around the main body 10 with an overlap of 50%.
  • Said tape is preferably >5 made of a fabric consisting of glass- fibre and mica paper pre- impregnated with insulating single-component epoxy resin.
  • the lamina 12 is glued to the main body 10, in particular to the insulating coating 11.
  • the insulating coating 13 coats the insulating coating 11 and the lamina 12 substantially along the first section 8 of the stator bar 6, whilst it coats the main body 10 along the second sections 9
  • the insulating coating 13 is made of the same material used for the insulating coating 11, i.e., a fabric consisting of glass-fibre and mica paper pre- impregnated with insulating single-component epoxy resin.
  • the conductive coating 14 substantially coats the insulating coating 13 along the first section 8 of the stator bar 6.
  • the conductive coating 14 is a tape wound with an overlap of 50% and made of conductive fabric, for example a glass-fibre tape impregnated with a resin containing graphite filler.
  • the conductive coating 14 provides the so-called external corona protection of the stator bar 6.
  • the lamina 12 made of conductive material renders the value of the electrical field on the external surface of the stator bar 6 substantially uniform. This enables a sensible reduction in the dissipative phenomena and in the partial discharges that normally jeopardize the duration and the service life of the electrical machine 1.
  • the lamina 12 made of conductive material in fact, substantially has the same potential as the elongated conductive elements 15 of the main body 10. Thanks to this property, the measurements made on stator bars according to the present invention have presented values of dissipation factor, understood as the amount of active energy that is dispersed, lower than the ones presented by the stator bars of the known art. Basically, the lamina 12 of conductive material attenuates considerably the dissipative effects that derive from the presence of the vacuoles in the insulating putty and of the air bubbles in the main body 10.
  • the present invention may be applied also to already existing electrical machines that have stator bars already equipped with traditional systems for protection - o —
  • the application of the lamina 12 made of conductive material is, in fact, possible on the majority of known stator bars and calls for minimal interventions during the maintenance operations necessary for re-insulation of the stator bars.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Iron Core Of Rotating Electric Machines (AREA)
  • Insulation, Fastening Of Motor, Generator Windings (AREA)

Abstract

L'invention porte sur une barre de stator pour une machine électrique (1), ayant deux extrémités opposées (7), laquelle barre de stator comporte un corps principal (10) défini par : une pluralité d'éléments conducteurs allongés sensiblement parallèles (15) et empilés sur des colonnes (16) qui sont disposées les unes le long des autres, chaque élément conducteur allongé (15) s'étendant le long d'un trajet comportant une pluralité de transpositions (20) d'une colonne (16) à l'autre; et un élément de remplissage (18) apte à remplir les espaces vides du corps principal (10), générés par les transpositions (20); la barre de stator (6) comportant de plus au moins une tôle (12) réalisée en un matériau conducteur, ayant une extrémité (24) électriquement connectée à un élément conducteur allongé (15) du corps principal (10).
EP07866839A 2007-12-21 2007-12-21 Barre de stator pour une machine électrique, et machine électrique comprenant ladite barre de stator Withdrawn EP2232677A2 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/IT2007/000908 WO2009081430A2 (fr) 2007-12-21 2007-12-21 Barre de stator pour une machine électrique, et machine électrique comprenant ladite barre de stator

Publications (1)

Publication Number Publication Date
EP2232677A2 true EP2232677A2 (fr) 2010-09-29

Family

ID=39719224

Family Applications (1)

Application Number Title Priority Date Filing Date
EP07866839A Withdrawn EP2232677A2 (fr) 2007-12-21 2007-12-21 Barre de stator pour une machine électrique, et machine électrique comprenant ladite barre de stator

Country Status (2)

Country Link
EP (1) EP2232677A2 (fr)
WO (1) WO2009081430A2 (fr)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8278795B2 (en) 2009-09-18 2012-10-02 Siemens Energy, Inc. Voltage grading structure in a high-voltage stator coil of an electromotive machine
US8872405B2 (en) * 2012-02-01 2014-10-28 Siemens Energy, Inc. High voltage stator coil with reduced power tip-up
EP2645539A1 (fr) * 2012-03-26 2013-10-02 Siemens Aktiengesellschaft Couches d'enroulement avec différents matériaux
ITMI20131440A1 (it) * 2013-09-03 2015-03-04 Wilic Sarl Macchina elettrica rotante, e metodo di assemblaggio di tale macchina elettrica rotante
CN104297649A (zh) * 2014-10-20 2015-01-21 西安交通大学 一种发电机定子线棒的热老化试验装置及方法

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19505020A1 (de) * 1995-02-15 1996-08-22 Abb Management Ag Verfahren und Vorrichtung zur Herstellung von Leiterstäben für dynamoelektrische Maschinen
US6663816B2 (en) * 2002-01-31 2003-12-16 General Electric Company Method of making a dynamoelectric machine conductor bar and method of making a conductor bar dynamoelectric machine
DE10304025A1 (de) * 2003-02-01 2004-08-05 Alstom Technology Ltd Roebelstab für eine elektrischen Maschine sowie Verfahren zum Herstellen eines solchen Roebelstabes

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2009081430A3 *

Also Published As

Publication number Publication date
WO2009081430A3 (fr) 2009-08-13
WO2009081430A8 (fr) 2010-02-25
WO2009081430A2 (fr) 2009-07-02

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