US3772627A - Shock-absorbing spring clamp for electric induction apparatus - Google Patents

Shock-absorbing spring clamp for electric induction apparatus Download PDF

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Publication number
US3772627A
US3772627A US00285723A US3772627DA US3772627A US 3772627 A US3772627 A US 3772627A US 00285723 A US00285723 A US 00285723A US 3772627D A US3772627D A US 3772627DA US 3772627 A US3772627 A US 3772627A
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United States
Prior art keywords
piston
cylinder
spring
induction apparatus
frame
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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
US00285723A
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English (en)
Inventor
S Wilk
B Lord
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General Electric Co
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General Electric Co
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Publication date
Application filed by General Electric Co filed Critical General Electric Co
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Publication of US3772627A publication Critical patent/US3772627A/en
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    • 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
    • H01F27/30—Fastening or clamping coils, windings, or parts thereof together; Fastening or mounting coils or windings on core, casing, or other support
    • H01F27/303—Clamping coils, windings or parts thereof together

Definitions

  • ABSTRACT An improved clamping means for retaining in position the windings of liquid-immersed electric induction apparatus of the high current type. Shock-absorbing spring clamps interposed between one end of power transformer windings and'a portion of the frame resiliently exert a follow-up clamping force on the windings under steady state conditions and resist by dashpot action any transient or shock force tending to cause winding displacement, such as electromagnetic force under short circuit conditions.
  • This invention relates to liquid-immersed electric induction apparatus of the type comprising a magnetic core about which one or more conductive windings are positioned, as in power transformers, reactors or the like. More specifically, this invention relates to an improved means for clamping and retaining the windings of large electric power transformers immersed in oil or other insulating liquid.
  • Spring-loaded devices have also been used in the past to obtain follow-up pressure on windings. In such devices, however, the springs have had to be inordinantly large in order directly to resist deformation forces resulting from short circuit currents. Also, in many instances, a great many clamping devices have been required, substantially contacting all free areas of each winding.
  • a further object of this invention is to provide a novel shock-absorbing spring clamp for transformer windings using special support plates to improve the utilization of space in the core and provide more efficient use of the winding clamp.
  • a magnetic core and coil assembly is provided, immersed in insulating liquid.
  • the coil or winding is firmly seated at one end of the core as a base, or frame, and a bearing ring or support plate is seated against the other movable end of the coil.
  • the bearing plate is spaced from the apparatus frame and a plurality of shock-absorbing spring clamps are interposed between the plate and frame.
  • a cylinder having a spring-pressed piston presses against the bearing plate to exert continuous clamping force upon the coil under steady state conditions.
  • Each cylinder is provided with a restricted aperture to permit limited ingress and egress of the ambient liquid so that the liquid imposes no appreciable resistance against the gradual piston movement.
  • any. transient displacement force as due to mechanical shock or electrical short circuit, is opposed by the dashpot action of the piston and cylinder.
  • the spring need be only sufficiently strong to initially compress the coil and retain it in position in normal operation, but need not be so strong that it can resist massive short circuit or other shock forces.
  • a secondary support plate, inclined to fit under the core is interposed between the bearing ring and the spring-pressed cylinder.
  • FIG. 1 is a partial side elevational view of a portion of a transformer embodying the clamping arrangement according to this invention, the casing being partly broken away to expose the interior structure;
  • FIG. 2 is a fragmentary top view of the clamping assembly of FIG. 1;
  • FIG. 3 is a sectional view taken on the line 3-3 of FIG. 1;
  • FIG. 4 is an axial cross-sectional view of a single one of the shock-absorbing spring clamps utilized in the as semblies of FIGS. 1 and 2.
  • a portion of a power transformer 10 comprising a casing 12 having a cover 14 and filled with electrical insulating liquid 16. Disposed in casing 12 is magnetizable core 18 having a vertical leg 20 surrounded by coils or windings 22.
  • the tranformer windings 22 are rigidly seated at its lower end against suitable frame structure such as a lower core clamp (not shown).
  • Axially adjacent the upper end of the winding 22 is a centrally apertured support plate or bearing ring 24.
  • This plate 24 is preferably formed of non-metallic material such as wood, fiber glass, epoxy resin or a resin-filled wood or paper.
  • plate 24 may be constructed of steel or similar metal if strength and electrical properties so require, provided that it is split radially or otherwise to break the electrical circuit to prevent induced circulating current and suitably spaced from the coil assembly 22 by insulating spacers. If desired, spacers may be interposed between the plate 24 and the movable end of coil 22 to provide for passage of liquid therebetween.
  • bearing ring or support plate 24 is a ring member, preferably non-metallic bearing against the upper end of coil assembly 22.
  • secondary support plates or bearing members 26 are provided, spaced about and resting on support plate 24.
  • four secondary support plates 26 are provided, equally spaced about bearing ring or support plate 24.
  • each secondary support plate 26 is beveled or tapered at its inner edge 28. This enables the inner plates 26 to fit under the yoke portion 30 of core 18.
  • a very thin bearing ring 24 may be used, to conserve space which is at a premium in the core window and still provide a strong clamp support for winding assembly 22.
  • Each secondary support plate 26 is pressed axially against bearing ring 24 and therefore against windings 22 by a spring-loaded clamp assembly 32.
  • Each clamp assembly 32 is slidably mounted in a flange 34 or 36 which forms a part of upper core clamp 38.
  • Each clamp assembly 32 has a metal foot member 40 which bears on the top of a secondary support plate 26, as shown.
  • Each clamping assembly 32 includes a cylinder 42 which is closed at its lower end by the foot 40.
  • foot 40 can be made integral with cylinder 42, or it may be welded to the lower end, as indicated at 44.
  • a small opening 46 is formed in cylinder 42, as shown in FIG. 4.
  • Mounted in cylinder 42 is a spring 48 which bears against foot 40.
  • the upper end of each cylinder 42 is open and slidably mounted therein is piston 50 having a ring seal 52.
  • the spring 48 is confined between piston 50 and foot 40.
  • Foot 40 is made as large as possible in conjunction with the top of support 26 to provide maximum clamping on windings
  • a piston rod 54 extends from piston 50 through a threaded flange 56 on core clamp 38 with locknut 58.
  • piston rod 54 is threaded as shown at 60 and is provided with a hex head top 62.
  • piston rod 54 may be four clamping assemblies 32 pressing against'the four secondary support plates 26 (shown in FIG. 2) in the manner above described.
  • adjusting screws operating on piston rods 54 may be used, or other means may be provided to compress springs 48.
  • the springs 48 will provide follow up pressure on windings 22 should the windings 22 settle or shrink in use. The springs 48 will also prevent displacement of windings 22 due to vibration.
  • springs 48 are sufficiently strong to compress the coil 22 to the desired degree and to hold it firmly in position against the lower yoke clamp. As will now be described, springs 48 need not be strong enough to fully resist short-circuit electromagnetic forces which tend to expand the coil 22 axially.
  • the entire casing 12 is filled with an insulating dielectric liquid 16 which may suitably be oil or askarel.
  • the core 18 and coil assembly 22 is immersed in the liquid 16, so that the clamping assemblies 32 are below the liquid level.
  • the cylinders 42 are filled with liquid 16, and the liquid 16 is free to enter or leave each cylinder 42 at a restricted rate through the aperture 46 in each cylinder 42. Presence of liquid 16 in each cylinder 42 and the restricted opening 46 in each cylinder 42 combine to resist any sudden movement between cylinders 42 and their associated pistons 50 by shockabsorbing dashpot action.
  • the cylinders 42 may either be open at one end, as shown, to provide free access of ambient liquid to one side of the piston 50, or may extend beyond the piston 50 to form an apertured chamber at both sides thereof.
  • each chamber must be apertured to provide for ingress and egress of liquid, and at least one aperture must appreciably restrict the flow of liquid.
  • initial adjustment of the clamping assemblies 32 is effected by tightening down the pistons 50 thus compressing the clamping springs 48 to apply the desired force against the bearing ring 24. Because this clamping force is resiliently applied by the compression springs 48, the pistons 50 and bearing ring 24 will follow long-term movement of the upper end of the coil 22 as the winding insulation shrinks or otherwise further compresses over a period of time. In such gradual movement the liquid in each shock-absorbing cylinder 42 does not inhibit movement between each cylinder 42 and its associated piston 50, because the slow rate of movement required can be accommodated by flow of liquid through the cylinder apertures 46.
  • anelectrical induction apparatus including a core, a core clamping frame and a conductive coil mounted on a portion of said core and fixedly seated at one end on said frame, resilient clamping means mounted between said frame and the other end of said coil, a bearing ring mounted on said other end of said coil and axially aligned therewith, a plurality of support plates mounted on said bearing ring, said resilient clamping means comprising a plurality of cylindrical members movably mounted in said frame, one end of each of said plurality of cylinders closed by a metal foot, each said metal foot engaging one of said plurality of support plates, a compression spring mounted in each of said cylinders, one end of said spring engaging said metal foot, a piston movably mounted in each said cylinder and engaging the other end of said spring, a piston rod secured to each said piston, means adjustably securing each said piston rod to said frame, whereby each said piston rod is adjustable to cause each piston to compress each said spring to provide resilient compressive force on said conductive coil, arestricte

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Coils Of Transformers For General Uses (AREA)
US00285723A 1972-09-01 1972-09-01 Shock-absorbing spring clamp for electric induction apparatus Expired - Lifetime US3772627A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US28572372A 1972-09-01 1972-09-01

Publications (1)

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US3772627A true US3772627A (en) 1973-11-13

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ID=23095448

Family Applications (1)

Application Number Title Priority Date Filing Date
US00285723A Expired - Lifetime US3772627A (en) 1972-09-01 1972-09-01 Shock-absorbing spring clamp for electric induction apparatus

Country Status (5)

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US (1) US3772627A (it)
BR (1) BR7305634D0 (it)
ES (1) ES417173A1 (it)
FR (1) FR2198234B1 (it)
IT (1) IT993653B (it)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1991019304A1 (de) * 1990-06-08 1991-12-12 Elin Energieversorgung Gesellschaft M.B.H. Transformator
US20080211617A1 (en) * 2004-12-27 2008-09-04 Abb Technology Ag Electrical Induction Device for High-Voltage Applications
US8235351B1 (en) * 2009-08-27 2012-08-07 Lockheed Martin Corporation Shock load isolation mounting
WO2018046618A1 (en) * 2016-09-09 2018-03-15 Abb Schweiz Ag Transformer assembly with shrinkage compensation
DE102016221114A1 (de) * 2016-10-26 2018-04-26 Siemens Aktiengesellschaft Elektrisches Gerät mit dynamischer Wicklungspressung
DE102016225414A1 (de) * 2016-12-19 2018-06-21 Siemens Aktiengesellschaft Vorrichtung zum Erzeugen einer Klemmkraft für eine Wicklung innerhalb eines mit einer Isolierflüssigkeit befüllten Kessels eines elektrischen Geräts
DE102017200673A1 (de) 2017-01-17 2018-07-19 Siemens Aktiengesellschaft Aktivteil mit Arretierungsmittel zum Einstellen des Wicklungsdruckes

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1311507A (en) * 1919-07-29 Vania
US1539670A (en) * 1920-02-24 1925-05-26 Gen Electric Stationary induction apparatus
US3156885A (en) * 1959-11-18 1964-11-10 Gen Electric Electrical apparatus and method of making same
US3172064A (en) * 1962-02-28 1965-03-02 Bbc Brown Boveri & Cie Spring-pressed arrangement for transformer and choke coil windings
US3467932A (en) * 1967-07-28 1969-09-16 Westinghouse Electric Corp Transformer construction

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE700453C (de) * 1938-03-24 1940-12-20 Siemens Schuckertwerke Akt Ges en
FR1273720A (fr) * 1960-11-16 1961-10-13 Thomson Houston Comp Francaise Perfectionnements à la fabrication des transformateurs
US3366907A (en) * 1965-10-22 1968-01-30 Westinghouse Electric Corp Core-form transformer pressure ring wound from magnetic material

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1311507A (en) * 1919-07-29 Vania
US1539670A (en) * 1920-02-24 1925-05-26 Gen Electric Stationary induction apparatus
US3156885A (en) * 1959-11-18 1964-11-10 Gen Electric Electrical apparatus and method of making same
US3172064A (en) * 1962-02-28 1965-03-02 Bbc Brown Boveri & Cie Spring-pressed arrangement for transformer and choke coil windings
US3467932A (en) * 1967-07-28 1969-09-16 Westinghouse Electric Corp Transformer construction

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1991019304A1 (de) * 1990-06-08 1991-12-12 Elin Energieversorgung Gesellschaft M.B.H. Transformator
US5327113A (en) * 1990-06-08 1994-07-05 Elin Energieversorgung Gmbh Transformer with coil compression
AT43U1 (de) * 1990-06-08 1994-11-25 Elin Energieversorgung Transformator
US20080211617A1 (en) * 2004-12-27 2008-09-04 Abb Technology Ag Electrical Induction Device for High-Voltage Applications
US7830233B2 (en) * 2004-12-27 2010-11-09 Abb Technology Ag Electrical induction device for high-voltage applications
US8235351B1 (en) * 2009-08-27 2012-08-07 Lockheed Martin Corporation Shock load isolation mounting
WO2018046618A1 (en) * 2016-09-09 2018-03-15 Abb Schweiz Ag Transformer assembly with shrinkage compensation
CN109906494A (zh) * 2016-09-09 2019-06-18 Abb瑞士股份有限公司 具有收缩补偿的变压器组件
US11456104B2 (en) * 2016-09-09 2022-09-27 Hitachi Energy Switzerland Ag Transformer assembly with shrinkage compensation
DE102016221114A1 (de) * 2016-10-26 2018-04-26 Siemens Aktiengesellschaft Elektrisches Gerät mit dynamischer Wicklungspressung
US10269483B2 (en) 2016-10-26 2019-04-23 Siemens Aktiengesellschaft Electrical device with dynamic winding pressing
DE102016225414A1 (de) * 2016-12-19 2018-06-21 Siemens Aktiengesellschaft Vorrichtung zum Erzeugen einer Klemmkraft für eine Wicklung innerhalb eines mit einer Isolierflüssigkeit befüllten Kessels eines elektrischen Geräts
DE102017200673A1 (de) 2017-01-17 2018-07-19 Siemens Aktiengesellschaft Aktivteil mit Arretierungsmittel zum Einstellen des Wicklungsdruckes

Also Published As

Publication number Publication date
FR2198234B1 (it) 1977-05-13
FR2198234A1 (it) 1974-03-29
IT993653B (it) 1975-09-30
ES417173A1 (es) 1976-03-16
BR7305634D0 (pt) 1974-08-22

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