US2795714A - Laminated end-shield for turbine generators - Google Patents

Laminated end-shield for turbine generators Download PDF

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Publication number
US2795714A
US2795714A US484613A US48461355A US2795714A US 2795714 A US2795714 A US 2795714A US 484613 A US484613 A US 484613A US 48461355 A US48461355 A US 48461355A US 2795714 A US2795714 A US 2795714A
Authority
US
United States
Prior art keywords
shield
laminations
stator
core
rotor
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 - Lifetime
Application number
US484613A
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English (en)
Inventor
Rene A Baudry
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.)
Westinghouse Electric Corp
Original Assignee
Westinghouse Electric Corp
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
Priority to CA555799A priority Critical patent/CA555799A/en
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to US484613A priority patent/US2795714A/en
Priority to DEW18260A priority patent/DE1014210B/de
Priority to CH341890D priority patent/CH341890A/de
Priority to JP190456A priority patent/JPS331957B1/ja
Application granted granted Critical
Publication of US2795714A publication Critical patent/US2795714A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/12—Stationary parts of the magnetic circuit
    • H02K1/18—Means for mounting or fastening magnetic stationary parts on to, or to, the stator structures
    • H02K1/185—Means for mounting or fastening magnetic stationary parts on to, or to, the stator structures to outer stators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/42—Means for preventing or reducing eddy-current losses in the winding heads, e.g. by shielding

Definitions

  • LAMINATED My invention relates to a turbine generator, which is a large, highspeed, two-pole alternating-current generator, having a cylindrical-core rotor-member carrying a fieldwinding, and a cylindrical-bore stator-member carrying a high-voltage alternating-current winding.
  • Such machines have sometimes heretofore been subject to stray-flux difficulties, necessitating certain special design-features for reducing eddy-current heating as a result of leakage fluxes in the end-winding spaces, causing overheating in certain parts of the ends of the stator-core.
  • My present invention relates to a stepped-back construction of a laminated magnetizable end-shield for reducing, to a low value, the eddy-current losses caused in the ends of the stator by the end leakage or stray flux of the machine.
  • Figure l is a somewhat simplified fragmentary longitudinal sectional view of the top half of one end of a machine embodying my invention.
  • Figure 2 is a fragmentary end-view of the end-shield on a somewhat larger scale, as seen from the section-plane IIII of Fig. 1.
  • the rotor-member has a slotted cylindrical rotor-core 4, carrying a rotorwinding 5 which is a direct-current field-winding having coil-sides disposed in the slots of the rotor-core.
  • the end-turns of the rotor-winding 5 are retained by a retaining ring 7, which may be of either magnetizable or nonmagnetizable material, each having advantages.
  • the rotor-member is carried by a shaft 8 which is journaled in suitable bearings 9 carried by the frame 11 of the machine.
  • the rotor-shaft 8 also carries a fan or blower 12 for ventilating purposes.
  • the stator-member 3 has a laminated stator-core 14 having a cylindrical bore which marks the outer boundary of the air gap between the stator and the rotor cores. Disposed at each end of the stator-core 14 is a slotted finger-ring member 15 which presses against that end of the stator-core.
  • the stator-core 14 carries the highvoltage alternating-current stator-Winding 16, having coilsides which are disposed in the slots of the stator-core and the finger-ring.
  • the finger-ring member 15 may advantageously be made of non-magnetic material, although sometimes it may be possible to make it of magnetizable material without causing too much stray-flux overheating.
  • the finger-ring members 15, at the two ends of the statorcore 14, are pressed against the core by means of endplates 20, and the end-plates at the two ends of the stator-core are drawn toward each other by means of 2,795,714 Patented June 11, 1957 "ice magnetizable material, the end plates 20 of the prior art have served the function of diverting some of the stray flux from the stator-core, so as to prevent the end-laminations of the core from becoming overheated by said stray flux.
  • the end-plates 20, or their equivalents have advantageously been made of a high-resistance metal, for reducing the eddy-current loss therein.
  • silicon-steel has frequently been used, because of its high resistivity and its resultant low eddy-current losses.
  • the stray or leakage-fluxes arise in the following manner.
  • the rotor-member 2 is the field-member of the machine, and the rotor-winding 5 is a direct-current fieldwinding.
  • the field-member In a large turbine-generator, the field-member has a two-pole field. Most of the flux which comes out of the north-pole portion of the rotor-core 4 crosses the air gap into the stator-core 14, interlinks with the stator winding 16, passes circumferentially halfway around the stator core, and comes out again at the air gap, returning into the rotor-core 4 at the south-pole portion which is diametrically opposite to the north-pole portion.
  • end-plates 20, or their equivalents have hitherto been made of magnetizable material, these end-plates have served as magnetic shields for receiving this stray flux, and intercepting it before it reaches the respective ends of the stator-core 14, so that most or much of the stray flux enters these previously used magnetizable end-plates 20, and then travels halfway around the plates, to come out again and return to the opposite pole of the rotor member.
  • each end-shield 24 which presses against each fingerring member 15, or against each end-plate 20 if such an end-plate is used in addition to the finger-ring, as shown.
  • Each end-shield 24 is disposed between its end-plate 20 and the elongated washers 22 which are engaged by the through-bolts 21.
  • Each magnetic end-shield 24, in accordance with my invention, is made of substantially radially disposed laminations, which are preferably punchings made from the same material as the punchings of the laminated stator-core 14.
  • the inner diameter of the innermost end-shield lamination 24athe one which is closest to its finger-ring memher 15 is large enough to fit outside of the coil-sides of the alternatingacurrent winding 16.
  • Successive laminaa tions, or groups of laminations, of the magnetic end-shield 24 have their inner diameters progressively stepped back, or increased in diameter, so as to reduce the broadside areas of said successive laminations or groups of laminations, in a manner suitable for the stray end-flux pattern of the generator.
  • the object of this stepped-back laminated end-shield construction is to facilitate the edgewise entry (or exit) of the stray flux into (or out of) the end-shield laminations, and to decrease the amount of stray flux which enters (or leaves) said end-shield laminations in a broadside direction.
  • the radial depth of the last end-shield lamination or group of laminations 24a shall be considerably less than one half of the radial depth of the innermost end-shield lamination 24a, measuring the radial depth from the inner radius to the outer radius of the lamination.
  • all of the laminations of my magnetic end-shield 24 shall have the same outer diameter as the stator-core 14, so that the end-shield laminations, as well as the stator-core laminations, may be built up, or mounted, on the outermost retaining or through-bolt 21, as by being provided with the usual mounting-notches 241 as shown in Fig. 2.
  • each magnetic end-shield 24 comprises a plurality of diverse groups of substantially, radially disposed laminations of different sizes, each group comprising one or more laminations. All of these groups, except the very last group, orthe group which is furthest away from the finger-ring member 15, as shownat 24a, have their inner diameters progressively stepped back (or -enlarged in relatively short steps; but the very last group 24a of the end-shield laminations contains a considerably larger number of laminations than any of the other groups, and it has its inner diameter stepped back in a relatively large step, so that its inner diameter is considerably larger than the inner diameter of the next adjacent lamination 24g of the end-shield.
  • This end-shield construction makes possible the use of a bent type of elongated washer 22, which has its outer portion extending radially across the last group of endshield laminations 24c, while an inner bent portion of the elongated Washer 22 extends radially across the exposed surface of the next adjacent end-shield lamination 24g, in the relatively large radial space or step which is provided by the large disparity between the inner diameter of the last group 24a as compared with the inner diameter of the next adjacent group 24g.
  • this end group 24c is thicker (comprising more laminations), and since the stray end-flux of the machine becomes somewhat diminished in intensity at points furthest away from the shaft 8, it may not be as necessary to serrate the inner diameters of this last group 24, although a serrated construction is preferred at this point, as shown. Because of the relatively small radial depth of this last group of end-shield laminations 24c, it is possible for the stray flux to divide itself, and enter this group of laminations at boththe outer diameter and the inner diameter thereof.
  • My improved end-plate construction is particularly needed in a modern heavy-duty machine in which the output has been very considerably increased over previous machines, volume for volume. This increased output is obtained by working the winding-conductors harder (by making them carry more current), and also perhaps by working the iron cores harder.
  • This increased current-output is obtained by filling the machine-frame 11 with hydrogen at pressures which may range between 30 and 100 pounds per square inch, gauge, and by using the now-well-established principle of direct conductorcooling of the stator and rotor windings 16 and 5, wherein the cooling medium, which is shown as being hydrogen, is directly circulated along these conductors in good thermal contact therewith, so as to directly withdraw the conductor-heat from the conductors themselves, as distinguished from withdrawing the conductor-heat from the stator and rotor cores, for example.
  • This direct conductor-heating is indicated, on the accompanying drawing, by the arrows representing the paths of the circulating hydrogen.
  • a two-pole alternating-current generator having a rotor-member .and stator-member; the rotor-member having a slotted rotor-core and a direct-current field-winding having coil-sides disposed in the slots of the rotor-core; and the stator-member having a slotted, cylindrical-bore, laminated stator-core, a slotted finger-ring member pressing against each end of the stator-core, an alternatingcurrent winding having coil-sides disposed in the slots of the stator-core and the finger-ring, and a laminated magnetic end-shield pressing against each finger-ring member; each magnetic end-shield having substantially radially disposed laminations; the inner diameter of the innermost end-shieldlamination, which is closest to its finger-ring member, being large enough to fit outside of the coil-sides of the alternating-current Winding; and successive laminations, or groups of laminations, of the mag netic end-shield having their inner diameters
  • a two-pole alternating-current generator having a rotor-member and a stator-member; the rotor-member having a slotted rotor-core and a direct-current field Winding having coil-sides disposed in the slots of the rotorcore; and the stator-member having a slotted, cylindricalbore, laminated stator-core, a slotted finger-ring member pressing against each end of the stator-core, an alternating-current Winding having coil-sides disposed in the slots of the stator-core and the finger-ring, and a laminated magnetic end-shield pressing against each finger-ring member; each magnetic end-shield comprising a plurality of diverse groups of substantially radially disposed laminations of difierent sizes, each group comprising one or more laminations; the inner diameter of the innermost group, which is closest to the finger-ring member, being large enough to fit outside of the coil-sides of the alternating-current winding; the next successive groups, all except the very last group,

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Iron Core Of Rotating Electric Machines (AREA)
US484613A 1955-01-28 1955-01-28 Laminated end-shield for turbine generators Expired - Lifetime US2795714A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
CA555799A CA555799A (en) 1955-01-28 Laminated end shield for turbine electric generators
US484613A US2795714A (en) 1955-01-28 1955-01-28 Laminated end-shield for turbine generators
DEW18260A DE1014210B (de) 1955-01-28 1956-01-20 Turbogenerator, dessen Blechpaket mittels Pressbolzen ueber eine aus ferromagnetischen Blechen bestehende Enddruckplatte zusammengehalten wird
CH341890D CH341890A (de) 1955-01-28 1956-01-26 Turbogenerator
JP190456A JPS331957B1 (de) 1955-01-28 1956-01-28

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
CA555799T
US1014210XA 1955-01-28 1955-01-28
US341890XA 1955-01-28 1955-01-28
US484613A US2795714A (en) 1955-01-28 1955-01-28 Laminated end-shield for turbine generators

Publications (1)

Publication Number Publication Date
US2795714A true US2795714A (en) 1957-06-11

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ID=76414812

Family Applications (1)

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US484613A Expired - Lifetime US2795714A (en) 1955-01-28 1955-01-28 Laminated end-shield for turbine generators

Country Status (4)

Country Link
US (1) US2795714A (de)
CA (1) CA555799A (de)
CH (1) CH341890A (de)
DE (1) DE1014210B (de)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3114063A (en) * 1959-09-26 1963-12-10 Allmanua Svenska Elek Ska Akti Means for reducing the stray losses in the space between the coil ends in synchronous generators
US3714477A (en) * 1971-08-23 1973-01-30 Gen Electric Combination flux shield and flux shunt for a dynamoelectric machine
DE2249354A1 (de) * 1971-10-19 1973-04-26 Gen Electric Flussabschirmung fuer generatorendzaehne
US4031422A (en) * 1975-09-02 1977-06-21 General Electric Company Gas cooled flux shield for dynamoelectric machine
US4152615A (en) * 1977-06-14 1979-05-01 Westinghouse Electric Corp. End iron axial flux damper system
US4205247A (en) * 1978-03-15 1980-05-27 General Electric Company Prime mover and methods
US4258281A (en) * 1979-08-17 1981-03-24 Westinghouse Electric Corp. Laminated flux shunt for dynamoelectric machine stator
US4281266A (en) * 1979-09-14 1981-07-28 Westinghouse Electric Corp. Dynamoelectric machine with flux screen
US4494030A (en) * 1981-11-04 1985-01-15 Westinghouse Electric Corp. Apparatus for preventing overflux damage to stator cores
US4638199A (en) * 1984-08-09 1987-01-20 Bbc Brown, Boveri & Company, Limited Stator body with laminated compression plates
US6346755B1 (en) * 2000-06-30 2002-02-12 General Electric Company Optimization of ventilating flow path at air gap exit in reverse flow generators
EP1811630A1 (de) 2006-01-24 2007-07-25 ALSTOM Technology Ltd Rotierende elektrische Maschine
US20070262658A1 (en) * 2006-03-31 2007-11-15 Oliver Drubel Magnetic Shield in the End Area of the Stator of a Three-Phase Generator
DE102009044942A1 (de) * 2009-09-24 2011-03-31 Robert Bosch Gmbh Hybriderregte, polumschaltbare elektrische Maschine
US8203249B1 (en) 2011-09-19 2012-06-19 Rao Dantam K Reducing the core-end heating in large power generators
US20130076197A1 (en) * 2011-09-24 2013-03-28 Aisin Seiki Kabushiki Kaisha Rotor for electric rotating machine and method for manufacturing the same

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1252659A (fr) * 1959-12-03 1961-02-03 Acec Plateau de serrage de tôles de stator
US4039872A (en) * 1976-06-01 1977-08-02 General Electric Company Guide vane assembly for reverse flow cooled dynamoelectric machine

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1689188A (en) * 1926-04-19 1928-10-23 Gen Electric Dynamo-electric machine

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH101704A (de) * 1921-09-09 1923-10-16 Siemens Schuckertwerke Gmbh Elektrische Maschine mit verminderten Wirbelstromverlusten.

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1689188A (en) * 1926-04-19 1928-10-23 Gen Electric Dynamo-electric machine

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3114063A (en) * 1959-09-26 1963-12-10 Allmanua Svenska Elek Ska Akti Means for reducing the stray losses in the space between the coil ends in synchronous generators
US3714477A (en) * 1971-08-23 1973-01-30 Gen Electric Combination flux shield and flux shunt for a dynamoelectric machine
DE2239567A1 (de) * 1971-08-23 1973-03-08 Gen Electric Kombinierte flussabschirmung und flussshunt fuer dynamoelektrische maschine
DE2249354A1 (de) * 1971-10-19 1973-04-26 Gen Electric Flussabschirmung fuer generatorendzaehne
US4031422A (en) * 1975-09-02 1977-06-21 General Electric Company Gas cooled flux shield for dynamoelectric machine
US4152615A (en) * 1977-06-14 1979-05-01 Westinghouse Electric Corp. End iron axial flux damper system
US4205247A (en) * 1978-03-15 1980-05-27 General Electric Company Prime mover and methods
US4258281A (en) * 1979-08-17 1981-03-24 Westinghouse Electric Corp. Laminated flux shunt for dynamoelectric machine stator
US4281266A (en) * 1979-09-14 1981-07-28 Westinghouse Electric Corp. Dynamoelectric machine with flux screen
US4494030A (en) * 1981-11-04 1985-01-15 Westinghouse Electric Corp. Apparatus for preventing overflux damage to stator cores
US4638199A (en) * 1984-08-09 1987-01-20 Bbc Brown, Boveri & Company, Limited Stator body with laminated compression plates
US6346755B1 (en) * 2000-06-30 2002-02-12 General Electric Company Optimization of ventilating flow path at air gap exit in reverse flow generators
EP1811630A1 (de) 2006-01-24 2007-07-25 ALSTOM Technology Ltd Rotierende elektrische Maschine
EP1811630B1 (de) * 2006-01-24 2013-11-20 Alstom Technology Ltd Rotierende elektrische Maschine
US20070262658A1 (en) * 2006-03-31 2007-11-15 Oliver Drubel Magnetic Shield in the End Area of the Stator of a Three-Phase Generator
DE102009044942A1 (de) * 2009-09-24 2011-03-31 Robert Bosch Gmbh Hybriderregte, polumschaltbare elektrische Maschine
US8203249B1 (en) 2011-09-19 2012-06-19 Rao Dantam K Reducing the core-end heating in large power generators
US20130076197A1 (en) * 2011-09-24 2013-03-28 Aisin Seiki Kabushiki Kaisha Rotor for electric rotating machine and method for manufacturing the same
US9225210B2 (en) * 2011-09-24 2015-12-29 Aisin Seiki Kabushiki Kaisha Rotor for electric rotating machine and method for manufacturing the same

Also Published As

Publication number Publication date
CA555799A (en) 1958-04-08
CH341890A (de) 1959-10-31
DE1014210B (de) 1957-08-22

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