ES2336585T3 - YOKE STRUCTURE THAT IS FOR THE LAMINATION NUCLEUS OF A STATIC ELECTRICAL MACHINE AND THIS COMPOSITE OF UNBELTED MEMBERS CUT TO MEASURE. - Google Patents

Abstract

A yoke structure for supporting and compressing the magnetic lamination core (32) of a static electrical machine, comprises at least four stress traverses (1-2, 3­4) tightened in pairs over the top branch and over the bottom branch of a lamination pack (32). Each stress traverse (1, 2, 3, 4) is composed of at least two tubular members (9) of rectangular cross section, parallel and spaced from one another and joined together by a plurality of brackets (11) having side wings with apertures to slidely receive there through the tubular members (9). At least two pairs of brackets (11) constitute supporting and blocking brackets for the resin body (29) encapsulating the windings of the electrical machine. The two outermost brackets (11) of each stress traverses (1, 2, 3,4) receive their said wings stress washers (12) for tie rods (5, 6, 7, 8) used to tighten the stress traverses.

Description

Yoke structure that is for the core of lamination of a static electric machine and is composed of non-soldier members cut to size.

The present invention relates generally to static electric machines having a laminated ferromagnetic core composed of sheets packed with high permeability material and windings encapsulated in resin.
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The structural architecture of the inductors, transformers, autotransformers and similar machines static electric, for nominal powers ranging from about few tens of kVA up to approximately 2000 kVA, includes yoke structures designed with dimensions and properties suitable mechanics to keep the core attached to pressure magnetic laminate and to withstand the weight of the machine electric

The yoke structures are practically load structures that typically use bolts or braces threaded and whose main purpose is to compress the core of lamination of the machine, after its final recomposition after having installed the resin body or bodies it contains (n) the windings of the machine, provide a means to sustain and immobilize the encapsulated resin coils in position, as well how to hold the entire machine with stability and provide a support for electrical connection terminals, eyelets lifting, fixings for suspension with cables, leaves teachers and similar accessories.

US 5 267 393 discloses a yoke structure of this type that has the characteristics of preamble of claim 1.

Typically, these yoke structures are carpentry products that are commonly manufactured in workshops specialized using custom cut and joined steel members by welding according to a workshop plan provided by the Electrical machine designer.

These welded steel load structures must be provided with holes in precisely defined sites in order to allow a correct assembly and assembly of the elements functional of the electric machine, the braces and the accessories.

Very often the construction of these Cargo structures are entrusted to external suppliers, and even when they are built inside the factory of manufacturer of electrical machinery, its construction, transportation and assembly are heavy operations due to the weight and large size of these structures, for machines of relatively great power. Such structures can hardly be moved by hand, that is, without the help of hoists and / or without the intervention of a suitable number of workers.

In addition, the predominant practice of commissioning external suppliers manufacturing these steel structures soldier involves supply problems out of control and dimensional inaccuracies that may compromise the ability to meet the contractual delivery deadlines established for the electric machine.

These relatively heavy welded structures provided with a multitude of holes located precisely for the passage of the braces and bolts for the mechanical union of the components during the final assembly phase of the machine must be pretreated and coated according to customer specifications  in order to impart corrosion resistance. Even these surface treatments of relatively heavy and burdensome welded steel metal structures can be quite laborious and expensive both in terms of treatment times As for the costs.

Finally, apart from certain resources handcrafted to simplify construction by complying with it time with geometric design tolerances, these structures They are intrinsically hard to normalize.

In light of the above, it is evident the need and / or utility of allowing an accomplishment economically favorable of these yoke structures with appropriate mechanical characteristics, even for machines of relatively great power, directly from the machine manufacturer electrical, using a limited number of components easily standardized of a size and weight such that it is still possible that a single person manipulate them manually, and that they can be together with simple operations without the need to perform welds or drill holes located precisely and that finally they can be put in place and pressed easily to complete the assembly of the machine, without devices elevators or an intervention of a plurality of workers.

These important goals, as well as a Remarkable design simplification and significant weight reduction of these charging structures of a static electric machine, they are achieved by a yoke structure of this invention according to the distinctive features of claim 1.

In practice, a yoke structure for press the lamination core and to hold a machine static electricity is composed, according to the present invention, of tubular members that have a cross section in general rectangular or square and are cut to size according to the needs, and a plurality of fixing brackets special scrolls of virtually identical structure that are displaced by at least one pair of tubular members identical, keeping them parallel and spaced apart.

The intermediate gap between two tubular members of rectangular cross section or square running parallel to the openings respectively aligned that are present on two parallel side wings of each fixing support allows the passage through braces threaded to press the magnetic core and other bolts of clamping, while the planar bases of origin of the supports of fixation coupled in a sliding way along the couple of parallel tubular members constitute support jaws and / or immobilization of a body or resin bodies that encapsulate the windings or coils of the electric machine.

Even the mechanical attachment to the structure of machine support feet, optionally equipped with wheels fixed or orientable, it can be conveniently established by cooperating couples of the same movable fixing brackets standardized, one of which can be fixed to a support foot and the another can move over the tubular members of a bottom sleeper of the yoke structure that squeezes the part or lower branch of the machine lamination core, with its respective parallel side wings interspersed on purpose.

The invention overcomes the drawbacks and the cost factor mentioned above, satisfying the needs and / or utility that have been commented previously.

The invention is defined in the attached claims.

Figure 1 is a three-dimensional view of a yoke structure made according to the present invention.

Figure 2 is a three-dimensional view in Exploded view of the yoke structure of Figure 1.

Figures 3, 4 and 5 are plan views, in elevation and side of the yoke structure of the figures precedents

Figures 6 and 7 are two views three-dimensional of a transformer that employs a structure of yoke of the rolling core and support of the resin bodies in which the windings of the transformer.

Figure 8 is a plan view of the transformer of Figures 6 and 7.

A sample embodiment of a structure of yoke of this invention is represented in Figures 1 to 5, in which is use the same numerical references for the same parts and the same details of the structure.

According to this embodiment, the yoke structure is It consists of four loading sleepers 1, 2, 3 and 4, which can be tightened in pairs by threaded braces 5, 6, 7 and 8, respectively from one to the other side of the top (the couple of sleepers 1 and 2) and from one to the other side of the bottom (the pair of sleepers 3 and 4) of the rolling core of the transformer not shown in this first series of figures which illustrate exclusively the components of the yoke structure in its coordinated function. Those other functional elements of the Electric machine are shown in a successive series of figures.

Each of the four loading sleepers 1, 2, 3 and 4 is composed of two tubular members 9 that have a section rectangular or square transverse and are parallel and are spaced from each other, to the cut ends of whose members tubular caps or caps 10 of pressure can be applied plastic to cover the sharp edges generated when cut to size the tubular members 9 from a stock of tubes rectangular or square of commercial length that can be had stored.

The two tubular members 9 are joined and held in a position where they are parallel and spaced apart each other by a plurality of fixing brackets 11 which are structurally identical and whose number is six in the realization of illustrated sample, each of them having a part that constitutes a planar base and two parallel lateral wings spaced from each other, each of said lateral wings having parallel two spaced openings of adequate size and shape for admit the two members in a scrollable way tubular 9, which are introduced through the respective aligned openings of the two parallel side wings of the fixing brackets 11.

Accordingly, the fixing brackets 11 are freely scrollable to an appropriate site along the pair of tubular members over which they are displaced

Those of the central pair of fixing brackets 11 and (for the realization of an illustrated sample of a three-phase transformer) those of the other two pairs of supports fixing 11 of each loading crossbeam constitute structures of cantilever jaws to support and / or immobilize the body of resin containing the resin encapsulated coils (the primary and secondary windings of the coil phase), as best will be described later with reference to the other sequence of Figures 6, 7 and 8.

The two fixing brackets 11 on the sides ends of each loading sleeper accommodate between their respective lateral wings that are in engagement with the tubular members to load washers 12 for two threaded braces 5, 6, 7 and 8 that cross the intermediate gap between the two tubular members 9 that make up the loading sleeper and are finally tightened by tightening the respective nuts 13, in order to compress the laminated core of the transformer along the upper and lower parts of the lamination core.

The fixing brackets 11 are practically identical and interchangeable, and can be used to compose the top pair of load sleepers 1 and 2 and to compose the lower pair of sleepers 3 and 4.

This aspect, together with the fact that the supports fixing 11 can be displaced by sliding to the correct site along the two tubular members 9 that they constitute the corresponding crossbeam and that fixing brackets can finally be fixed on site correct by means of simple fixing screws, it allows a remarkable normalization level

In practice, with two or few more sizes of 9 tubes used to compose the loading sleepers and with two or few more standard sizes of fixing brackets 11 movable such that they provide the appropriate characteristics mechanical and appropriate sizes of aligned openings practiced through the spaced parallel side wings for different sizes and different characteristics mechanics of the different tubes 9 that can be cut to the length required according to the design needs of the machine, it is possible to compose yoke structures for a wide range of electric machines designed for nominal powers that can be generally between 50 and 2000 kVA, which is minimized the inventory of components to manage.

The necessary mechanical connection between upper sleepers 1 and 2 and the lower sleepers of Load 3 and 4 is also done without requiring welding and using in instead, even for this purpose, components that can be easily standardized, without requiring precise drilling of the loading sleepers to be joined.

In the sample embodiment illustrated, the mechanical connection between a top loading sleeper and the lower crossbar load (on the same side of the machine) is established by three rising columns of steel plate 14 whose constitution can best be seen in the exploded view of Figure 2.

The hole 15 at the lower end of the ascending columns 14 can be threaded to accept the screw of clamping 16 passing through the intermediate space of separation between the two tubular members that constitute the lower crossbar load 3 and 4, using a washer 17.

The hole 18 at the upper end of the ascending column 14 admits a bolt 19 that joins it to the end of a lifting eye 20 or a connecting member 20 'which can be preinstalled on the inside surface of the crossbar upper load by tightening the screw 21 that passes through the intermediate gap between the two tubular members 9 that make up the upper naughty of load 1 and 2, which press the lifting eye 20 or the connecting member 20 'against the inner surface of the two tubular members 9 that make up the Naughty cargo.

According to the preferred embodiment shown in The figures, the core lamination tightening machine takes place by means of elastic distribution spacers 22 and load transmission that can be made of corrugated sheet of steel. The profile and height of the undulations and mechanical and elastic properties of these corrugated spacers 22 are designed in a way that virtually prevents contact direct from the flat ascending connection columns 14 and from the rear of the fixing brackets 11 with the core of lamination.

Another positive effect of using these elastic wavy spacers 22 is to determine a space intermediate separation between the loading crossbar and the surface planar of the first lamination of the core of the magnetic core. This favors heat dissipation by avoiding impeding or disturb the natural convective circulation of ambient air to through the intermediate separation space and through the undulations of elastic spacers 22.

The peculiar design of the fixing bracket 11 facilitates the realization of support feet 23 and 24, if required. Although these support feet can be composed using the same tubular members of rectangular cross section that are used to constitute the four sleepers of the structure of yoke, other steel profiles can be used as in the sample embodiment illustrated in the figures, where Support feet are made using pairs of steel profiles in U, respectively 23 'and 24'.

The 23 'and 24' U profiles of each pair are mechanically joined by a plurality of connecting U-pieces common 25 that have a series of pre-drilled holes or prints 26.

Even in this case, the mechanical union of two feet 23 and 24 to the lower pair of cargo sleepers 3 and 4 of the yoke structure is done remarkably simply, without requiring any welding or precise drilling operations, using four additional fixing brackets for this purpose  11 'inserted upside down over the tubular members 9 of the bottom sleepers 3 and 4 together with the fixing brackets more interiors of the two lateral pairs of fixing brackets, interspersing their respective lateral wings, as can be seen Easily in the figures.

Feet 23 and 24 are positioned in such a way that a pre-drilled hole 26 of the connecting U-pieces 25 of the feet are in alignment with one of the pre-drilled holes that are present through the flat base of the support 11 'fixing, which is installed on purpose upside down, thus allowing the mechanical joint tightening bolt 27 that passes through the hole 26 of the bridge type junction piece 25 and through the hole 28 of the base of the additional fixing bracket 11 'mounted upside down.

According to the preferred embodiment illustrated, fixing brackets 11 and 11 ', and in particular the profile of the two parallel side wings of the fixing brackets, have (has) a trapezoidal shape. This facilitates access and assembly and immobilization operations of the resin bodies of the windings and the necessary recomposition of the upper branch of the machine lamination core, together with the characteristic of that both the lifting eyelet 20 and the connecting members 20 ' can be turned down by loosening bolts 19, in order to remove "obstructions" during the recomposition of the lamination of the upper arm of the magnetic core.

Figures 6 and 7 are three-dimensional views from different observation points and Figure 8 is a view in plant of a fully assembled three-phase transformer that has a yoke structure that can be composed and assembled with uniquely lightweight components without requiring welds or precise hole drilling operations according to the present invention.

As can be seen in the figures, the Resin bodies 29 of the resin encapsulated windings for the three phases of the transformer are held and immobilized from stable way in position using for each resin body of the corresponding primary and secondary windings of a phase of the machine four gaskets or covers radially plastic 30 preinstalled in the parts that constitute the planar bases of the respective fixing brackets 11.

After positioning the resin bodies 29 on the respective four fixing brackets 11 provided with plastic covers 30 suitably coupled along the lower sleepers 3 and 4 of the yoke, the resin bodies 29 they are immobilized by positioning the four fixing brackets 11 of retention also provided with plastic covers 30, and screwing and tightening the locking screws 31.

Naturally, after completing the installation of the resin bodies 29 of the windings of the three-phase transformer, the upper branch of the core is recomposed lamination constituting the magnetic core 32 of the machine.

Finally it can also be tightened last place the pair of top sleepers 1 and 2 of the yoke structure acting on the respective braces 5 and 6.

None of the four clamping straps 5, 6, 7 and 8 crosses the magnetic lamination core, thus avoiding electrical isolation problems of stray currents induced in the ferromagnetic core. The braces act on the ends of the load sleepers that are beyond the profile of the rolling core 32.

It has been proven that the tightening, interposing the elastic elements 22 described above, which is effected tightening the two braces at the respective ends of the composite load sleepers, is significantly more effective at be carried out against an elastic reaction force of the slightly curved load members, which is determined pre-sealing the tubular members 9 cut to size. Through A dedicated mechanical testing campaign has verified that imparting to tubular members 9 of cross section rectangular cut to size certain curvature to determine, in the absence of loading, a maximum arrow at the center point of the member length included, in terms of the relationship arrow / length, between 0.005 and 0.015 (between 0.5 and 1.5%) and mounting the curved members with the convex surface facing to the lamination core to be compressed, the tightening is more efficient and the Tubular limb size can be reduced without risk to minimize your weight

All the components of the yoke structure of the invention are preferably of good steel mechanical characteristics, and preferably of a steel having a relatively high elastic limit.

The remarkable level of standardization that is made possible by the constitution of the yoke structure of the present invention makes it economical to maintain adequate inventories of prefabricated components, already treated against corrosion, thus avoiding delayed situations that often occur with The traditional state-of-the-art welded carpentry technique for final coating treatments of ad hoc structures.

The sample realization shown in the Figures 6, 7 and 8 correspond to a three-phase transformer for electric power distribution that has the capacity to handle a maximum nominal power of 630 kVA, with an insulation of 20,000 V.

The profile of the rolling core 32 had a height of 1,235 mm and a width of 1,170 mm, and the core had a 210 mm diameter.

Tubular members 9 of cross section square were of steel F 360, with dimensions of 30 mm x 30 mm and a wall thickness of 3 mm. These tubular members were pre-sealed to produce a maximum arrow in the center 15 mm, which corresponds to an arrow / length ratio of the tubular members of 0.01 (1%).

The fixing brackets 11, 11 'were made of sheet steel that had a thickness of 3 mm, the height of the lateral wings was 105 mm, and the separation distance between two side wings was 60 mm.

The threaded braces 5, 6, 7 and 8 were 20 mm distance from the core of rolling.

Load washers 12 were made by welded with welded steel plate that had a width of 75 mm and a thickness of 8 mm.

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References cited in the description

This list of references cited by the applicant is provided only as information for the reader and is not part of the European patent document. Although the references were compiled with great care, the possibility of errors or omissions cannot be excluded, and the EPO disclaims any responsibility in this regard .

Patent documents cited in the description

US 5267393 A [0004]

Claims (7)

1. Yoke structure that is to support and compress the rolling magnetic yoke (32) of a machine static electric and comprises at least four charging sleepers (1-2, 3-4) that are tight in pairs by threaded braces (5, 6, 7, 8), respectively of one on the other side of the upper branch and from one on the other side of the lower branch of a rolling package constituting said magnetic core (32), and at least four fixing brackets of support and immobilization of at least one resin body that It contains windings of the electric machine, protruding said cantilever fixing brackets of the pair of load sleepers pressed from one to the other side of said lower branch of the core of lamination and the pair of tight load sleepers from each other other side of the upper branch of the nucleus; characterized by the fact that each of said loading sleepers (1, 2, 3, 4) consists of at least two tubular members (9) of section rectangular or square transverse that are parallel and are spaced from each other and are joined by a plurality of supports fixing (11) having at least two parallel side wings that each have at least two spaced openings and one proper way to admit scrolling through it to said tubular members (9) that are introduced parallel to through the aligned openings of the parallel side wings of the fixing brackets (11) which are positionally positioned movable along the length of said tubular members (9); constituting at least two pairs of said fixing brackets (11) displaceably coupled over said spaced and parallel tubular members of each of said pairs of cargo sleepers (1-2, 3-4) said support fixing brackets e immobilization of said resin body (29); admitting the two fixing brackets (11) more exteriors of each of said loading sleepers (1, 2, 3, 4) between said parallel side wings coupled above said tubular members (9) to load washers (12) for two braces (5, 6, 7, 8) that pass through the intermediate space of separation between the two parallel tubular members (9) of two facing sleepers (1-2, 3-4), said braces being tensioned for compress the lamination core along said branches top and bottom of the magnetic lamination package (32). 2. Yoke structure according to claim 1, characterized in that the ends of said load beams (1-2, 3-4) carrying said fixing supports (11) which are the outermost protrude beyond of the profile of said rolling core (32) and said threaded braces (5, 6, 7, 8) are located externally with respect to said magnetic core (32). 3. Yoke structure according to claim 1, characterized in that said tubular members (9) parallel and spaced apart from each other constituting said load sleepers (1, 2, 3, 4) are curved so as to have in the center a maximum arrow between 0.5% and 1.5% of its length. 4. Yoke structure according to claim 1, characterized in that each loading cross member (1, 2, 3, 4) which is composed of said spaced and parallel tubular members (9) comprises at least six of said support brackets fixing (11) with openings of the aligned lateral wings that are introduced by displacement over the tubular members (9); being at least two of said supports of fixing (11) of the loading sleepers (3, 4) that are tightened one on the other side of the lower branch of the rolling core (32) fixed at a specific site by means of a fixing screw or an equivalent fixing element and respectively attached to one and to the other two feet (23, 24) of the yoke structure. 5. Yoke structure according to claim 4, characterized in that each of said feet (23, 24) is composed of a pair of parallel and spaced U members (23 ', 24') that are joined by a plurality of connecting U-pieces (25), those of the innermost pair of connecting U-pieces (25 ') being mechanically attached to said two fixing brackets (11) of said sleepers (3, 4) pressed together on the other side of the lower arm of the rolling core (32). 6. Yoke structure according to claim 1, characterized in that said lateral wings of said fixing brackets (11) have a trapezoidal profile with the maximum width in correspondence with the right-angled bending edge of said wings with respect to to the part that constitutes the flat base of the fixing brackets, and said fixing brackets (11) are introduced over the respective tubular members with the part constituting the flat base facing the mid-plane of the height of the magnetic core (32 ). 7. Yoke structure according to claim 5, characterized in that said mechanical joints are established by means of four additional fixing brackets (11 ') which are introduced by sliding in pairs and vice versa along the tubular members (9 ) of one (3) and the other (4) loading crossbar, respectively, and interspersing its parallel lateral wings with the lateral wings of said two fixing brackets (11) fixed in position.