WO1997045937A1 - A device in the stator of a rotating electric machine - Google Patents
A device in the stator of a rotating electric machine Download PDFInfo
- Publication number
- WO1997045937A1 WO1997045937A1 PCT/SE1997/000904 SE9700904W WO9745937A1 WO 1997045937 A1 WO1997045937 A1 WO 1997045937A1 SE 9700904 W SE9700904 W SE 9700904W WO 9745937 A1 WO9745937 A1 WO 9745937A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- stator
- electric machine
- rotating electric
- machine according
- teeth
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K3/00—Details of windings
- H02K3/46—Fastening of windings on the stator or rotor structure
- H02K3/48—Fastening of windings on the stator or rotor structure in slots
- H02K3/487—Slot-closing devices
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/28—Coils; Windings; Conductive connections
- H01F27/288—Shielding
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K2203/00—Specific aspects not provided for in the other groups of this subclass relating to the windings
- H02K2203/15—Machines characterised by cable windings, e.g. high-voltage cables, ribbon cables
Definitions
- the present invention relates to a device for increasing the mechanical rigidity and natural frequency of the stator in a rotating electric machine and prevent damaging oscillations occurring between the stator teeth.
- the water- and oil-cooled synchronous machine described in J. Elektrotechnika is intended for voltages up to 20 kV.
- the article describes a new insulating system consisting of oil /paper insulation, which makes it possible to immerse the stator completely in oil. The oil can then be used as a coolant while at the same time using it as insulation.
- a dielectric oil-separating ring is provided at the internal surface of the core.
- the stator winding is made from conductors with an oval hollow shape provided with oil and paper insulation. The coil sides with their insulation are secured to the slots made with rectangular cross section by means of wedges.
- coolant oil is used both in the hollow conductors and in holes in the stator walls.
- Such cooling systems entail a large number of connections of both oil and electricity at the coil ends.
- the thick insulation also entails an increased radius of curvature of the conductors, which in turn results in an increased size of the winding overhang.
- stator part of a synchronous machine which comprises a laminated magnetic core of electrical steel with trapezoidal slots for the stator winding.
- the slots are tapered since the need of insulation of the stator winding is less towards the interior of the rotor where that part of the winding which is located nearest the neutral point is located.
- stator part comprises a dielectric oil-separating cylinder nearest the inner surface of the core which may increase the magnetization requirement relative to a machine without this ring.
- the stator winding is made of oil-immersed cables with the same diameter for each winding layer. The layers are separated from each other by means of spacers in the slots and secured by wedges.
- the winding comprises two so-called half -windings connected in series.
- One of the two half-windings is located, centred, inside an insulation sleeve.
- the conductors of the stator winding are cooled by surrounding oil.
- the disadvantages with such a large quantity of oil in the system are the risk of leakage and the considerable amount of cleaning work which may result from a fault condition.
- Those parts of the insulation sleeve which are located outside the slots have a cylindrical part and a conical termination reinforced with current-carrying layers, the duty of which is to control the electric field strength in the region where the cable enters the end winding.
- the oil-cooled stator winding comprises a conventional high-voltage cable with the same dimension for all the layers.
- the cable is placed in stator slots formed as circular, radially disposed openings corresponding to the cross-section area of the cable and the necessary space for fixing and for coolant.
- the different radially located layers of the winding are surrounded by and fixed in insulated tubes. Insulating spacers fix the tubes in the stator slot.
- an internal dielectric ring is also needed here for sealing the coolant against the internal air gap.
- the design shows no tapering of the insulation or of the stator slots. The design exhibits a very narrow radial waist between the different stator slots, which implies a large slot leakage flux which significantly influences the magnetization requirement of the machine.
- the problem addressed by the invention appears in connection with a high-voltage electric alternating current machine, primarily intended as a generator in a power station for generating electric power.
- Such machines have conventionally been designed for voltages in the range 15-30 kV and 30 kV has normally been considered to be an upper limit.
- the voltage of the machine can be increased to such levels that it can be connected directly to the power network without an intermediate transformer.
- the step-up transformer is thus ekminated.
- stator This concept generally requires that the slots in which the cables are placed in the stator to be deeper than with conventional technology (thicker insulation due to higher voltage and more turns in the winding). This entails new problems with regard to mechanical natural frequencies in the stator teeth between the stator slots.
- a stator with deep slots may be subjected to damaging vibrations at the air gap due to resonance with disturbing force, typically electromagnetic forces with a frequency of 100 Hz for a machine having a norrtinal output frequency of 50 Hz.
- the object of the present invention is to solve this problem and thus prevent oscillations between the stator teeth. This object is achieved with the method and the device defined in the appended claims.
- Figure 1 shows a cross section through the insulated electrical conductor which is used in conjunction with the invention and is here termed a cable
- Figure 2 shows an axial view of a sector in a stator core
- Figures 3 and 4 show axial views of the end of a slot situated at the air gap in the stator core, according to two embodiments of the invention
- Figure 5 shows an axial view of a sector of a stator core according to a third embodiment of the invention
- Figure 6 shows an axial view of a sector of a stator core with yet another application of the device according to the invention
- Figure 7 shows an axial section through the stator part corresponding to Figure 6, and Figures 8 and 9 show a radial and an axial view, respectively, partially in section, of the end part of the stator core near the air gap.
- Figure 1 illustrates a cross-sectional view of an insulated electric conductor or cable 1, used in conjunction with the present invention.
- the cable 1 comprises a conductor 2 with circular cross section, consisting of a number of strands and made of copper, for instance.
- This conductor 2 is arranged in the middle of the cable 1.
- Around the conductor 2 is a first semiconducting layer 3.
- Around the first semiconducting layer 3 is an insulating layer 4, e.g., XLPE insulation.
- Around the layer of insulation 4 is a second semiconducting layer 5.
- the cable does not include the outer protective sleeve which normally surrounds a cable for power distribution.
- FIG. 2 shows part of a stator lamination 6 intended for a new high- voltage alternating current generator.
- a spacer or a slot wedge 11 is inserted into the opening of the slot 8.
- the wedge is made of a material which is electrically non-conducting and is non-magnetic, rigid and strong, e.g., glassfibre-reinforced plastic (epoxy plastic), and extends across the entire axial length of the stator.
- This wedge is inserted with radial force as indicated by the arrow 12 during assembly, thus providing tangentially stiff connections between the stator teeth at the air gap all round the stator. This stiff connection increases the natural frequency and offers greatly increased rigidity in each individual tooth, and even increased flexural rigidity in the whole stator core.
- Figure 4 shows another embodiment of the device according to the invention.
- the wedge 11 has inverted wedge shape, as also the wedge surfaces cooperating therewith on the stator teeth 10.
- the wedge Upon being placed under pressure the wedge is in this case pressed out towards the air gap, making use of the cable 1 radially fixed innermost in its seat.
- a tube known per se which, upon being pressurized expands between the cable 1 and wedge 11, a tube 14 which is filled with, e.g., liquid epoxy compound which hardens under pressure.
- Such a tube has been used previously in conventional generators in order to press the conductors forming the winding into the slot outwardly towards the bottom of the slot, a function not at all demanded in the present case.
- FIG. 5 A third embodiment is shown in Figure 5.
- the tangential compression between the stator teeth is achieved via the wedges 11 by a tensile force F being applied to the stator core 15 through an external arrangement in the form of tie-rods, cords 16 or the outer stator frame 17.
- the stator consisting of segments is joined together at final assembly so that when tensile force is applied to the outer arrangement, a counter compressive force is obtained in the stator teeth and wedges at the air gap.
- the spacers 11 are wedge-shaped, as described. However, they may also be parallel-epipedic, in which case the tangentially stiff connection can be achieved in accordance with Figure 5. Adhesive joints may also be arranged between the spacers 11 and stator teeth 10, either as the sole fixing means or prior to fixing by means of tangential clamping.
- FIGS 6-9 illustrate how the slot wedges according to the invention can also be utilized to achieve axial compressive pre-stressing of the stator core 15.
- the pressure fingers 18 are arranged on each side of the core 15, immediately opposite the stator teeth 10, to act as a force-transmission device to convert the tensile force in the wedges 11 to a uniformly distributed compressive force in the stator core 15.
- the ends of the wedges are joined together by means of transverse pieces 19 which are able to cooperate with the pressure fingers 18.
- the transverse pieces 19 in the embodiment shown are joined to the wedges 11 by means of pins 20, slidable in the transverse pieces 19, which are loaded outwardly by means of a compression spring 21.
- One end of the pressure fingers 18 engages below the transverse piece 19, enabling it to load the transverse piece and thus the wedges in a direction outwards from the laminated core 15.
- the other end of the pressure fingers 18 is clamped between two devices 22 and 23 connected to the stator frame 17.
- the tensile force in the wedge 11 can be converted to a compressive force in the stator core 15 via nuts 24 cooperating with screw threading 25 on the edges of the wedges 11.
- the compressive force from the nuts 24 is transmitted to the stator core 15 via plates 26 of, e.g., laminated glassfibre.
- slot wedges used for tangential positioning of the stator teeth are also utilized advantageously as tie-rods to achieve the requisite compressive stress in the stator core.
- the invention is also applicable to other electric machines such as double- fed machines, applications in asynchronous static current converter cascades, outer pole machines and synchronous flux machines, particularly if their windings are manufactured with insulated electric conductors of the type described in the introduction, and preferably in the voltage range 36-800 kV.
Abstract
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP97924480A EP1016191A1 (en) | 1996-05-29 | 1997-05-27 | A device in the stator of a rotating electric machine |
JP09542219A JP2000512835A (en) | 1996-05-29 | 1997-05-27 | Equipment of rotating electric machine stator |
AU29893/97A AU2989397A (en) | 1996-05-29 | 1997-05-27 | A device in the stator of a rotating electric machine |
EA199801057A EA001098B1 (en) | 1996-05-29 | 1997-05-27 | A device in the stator of a rotating electric machine |
BR9709613A BR9709613A (en) | 1996-05-29 | 1997-05-27 | Stator device of a rotating electrical machine |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE9602079-7 | 1996-05-29 | ||
SE9602083A SE9602083D0 (en) | 1996-05-29 | 1996-05-29 | Device at the stator in a rotating electric machine |
SE9602083-9 | 1996-05-29 | ||
SE9602079A SE9602079D0 (en) | 1996-05-29 | 1996-05-29 | Rotating electric machines with magnetic circuit for high voltage and a method for manufacturing the same |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1997045937A1 true WO1997045937A1 (en) | 1997-12-04 |
Family
ID=26662641
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/SE1997/000904 WO1997045937A1 (en) | 1996-05-29 | 1997-05-27 | A device in the stator of a rotating electric machine |
Country Status (8)
Country | Link |
---|---|
EP (1) | EP1016191A1 (en) |
JP (1) | JP2000512835A (en) |
CN (1) | CN1220050A (en) |
AU (1) | AU2989397A (en) |
BR (1) | BR9709613A (en) |
CA (1) | CA2255725A1 (en) |
EA (1) | EA001098B1 (en) |
WO (1) | WO1997045937A1 (en) |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN104365000A (en) | 2012-01-26 | 2015-02-18 | 大陆汽车有限公司 | Rotor for a rotating electric machine |
EP2807727B1 (en) | 2012-01-26 | 2020-03-11 | Vitesco Technologies GmbH | Rotor for a rotating electric machine and rotating electric machine |
DE202012000842U1 (en) | 2012-01-26 | 2012-02-03 | Continental Automotive Gmbh | Rotor for a rotating electric machine and electric motor |
DE102015211355A1 (en) * | 2015-06-19 | 2016-12-22 | Wobben Properties Gmbh | Forming coil, winding structure and stator of a generator of a wind turbine and method for producing a stator |
KR102485025B1 (en) * | 2015-09-14 | 2023-01-05 | 엘지이노텍 주식회사 | Integrated cable and motor assembly including the same |
WO2020183526A1 (en) * | 2019-03-08 | 2020-09-17 | 三菱電機株式会社 | Rotary electric machine inspection method, rotary electric machine, and rotary electric machine inspection system |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3158770A (en) * | 1960-12-14 | 1964-11-24 | Gen Electric | Armature bar vibration damping arrangement |
US3437858A (en) * | 1966-11-17 | 1969-04-08 | Glastic Corp | Slot wedge for electric motors or generators |
US3444407A (en) * | 1966-07-20 | 1969-05-13 | Gen Electric | Rigid conductor bars in dynamoelectric machine slots |
US3932779A (en) * | 1973-03-22 | 1976-01-13 | Allmanna Svenska Elektriska Aktiebolaget | Turbo-generator rotor with a rotor winding and a method of securing the rotor winding |
FR2305879A1 (en) * | 1975-02-18 | 1976-10-22 | Dukshtau Alexandr | Stator with end plate and finger assembly of reduced height - has nonmagnetic steel pressure fingers located in grooves |
US4200818A (en) * | 1978-08-01 | 1980-04-29 | Westinghouse Electric Corp. | Resin impregnated aromatic polyamide covered glass based slot wedge for large dynamoelectric machines |
US4425521A (en) * | 1982-06-03 | 1984-01-10 | General Electric Company | Magnetic slot wedge with low average permeability and high mechanical strength |
US5036165A (en) * | 1984-08-23 | 1991-07-30 | General Electric Co. | Semi-conducting layer for insulated electrical conductors |
DE4233558A1 (en) * | 1992-09-30 | 1994-03-31 | Siemens Ag | Electric machine with resin-filled inserts in winding slots - incorporates foil folded to form bag from which resin can escape on compression for adhesive bond to winding. |
-
1997
- 1997-05-27 CA CA 2255725 patent/CA2255725A1/en not_active Abandoned
- 1997-05-27 EA EA199801057A patent/EA001098B1/en not_active IP Right Cessation
- 1997-05-27 EP EP97924480A patent/EP1016191A1/en not_active Withdrawn
- 1997-05-27 JP JP09542219A patent/JP2000512835A/en active Pending
- 1997-05-27 CN CN 97195052 patent/CN1220050A/en active Pending
- 1997-05-27 BR BR9709613A patent/BR9709613A/en not_active Application Discontinuation
- 1997-05-27 AU AU29893/97A patent/AU2989397A/en not_active Abandoned
- 1997-05-27 WO PCT/SE1997/000904 patent/WO1997045937A1/en not_active Application Discontinuation
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3158770A (en) * | 1960-12-14 | 1964-11-24 | Gen Electric | Armature bar vibration damping arrangement |
US3444407A (en) * | 1966-07-20 | 1969-05-13 | Gen Electric | Rigid conductor bars in dynamoelectric machine slots |
US3437858A (en) * | 1966-11-17 | 1969-04-08 | Glastic Corp | Slot wedge for electric motors or generators |
US3932779A (en) * | 1973-03-22 | 1976-01-13 | Allmanna Svenska Elektriska Aktiebolaget | Turbo-generator rotor with a rotor winding and a method of securing the rotor winding |
FR2305879A1 (en) * | 1975-02-18 | 1976-10-22 | Dukshtau Alexandr | Stator with end plate and finger assembly of reduced height - has nonmagnetic steel pressure fingers located in grooves |
US4200818A (en) * | 1978-08-01 | 1980-04-29 | Westinghouse Electric Corp. | Resin impregnated aromatic polyamide covered glass based slot wedge for large dynamoelectric machines |
US4425521A (en) * | 1982-06-03 | 1984-01-10 | General Electric Company | Magnetic slot wedge with low average permeability and high mechanical strength |
US5036165A (en) * | 1984-08-23 | 1991-07-30 | General Electric Co. | Semi-conducting layer for insulated electrical conductors |
DE4233558A1 (en) * | 1992-09-30 | 1994-03-31 | Siemens Ag | Electric machine with resin-filled inserts in winding slots - incorporates foil folded to form bag from which resin can escape on compression for adhesive bond to winding. |
Also Published As
Publication number | Publication date |
---|---|
EA199801057A1 (en) | 1999-08-26 |
BR9709613A (en) | 1999-08-10 |
CA2255725A1 (en) | 1997-12-04 |
AU2989397A (en) | 1998-01-05 |
CN1220050A (en) | 1999-06-16 |
JP2000512835A (en) | 2000-09-26 |
EA001098B1 (en) | 2000-10-30 |
EP1016191A1 (en) | 2000-07-05 |
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