CN1011840B - Mold transformer - Google Patents

Abstract

To enable the upper and lower ends of an swollen part of resin to be notched without any cracks apt to be generated at the corners and to economize the amount of used resin, by winding a ribbon of organic fibers having high impregnating ability to the resin on the outer periphery of coils constituting an external winding. A plurality of coils 41-45 are aligned along the axial direction of windings, each of these coils being formed by winding conductor plates together with an insulating foil interposed therebetween, from the inside to the outside. The coils are totally resin molded to form an external winding 1. Terminal fittings 21, 22 are buried in the swollen part 5 of the molding resin. Ribbon of inorganic fibers presenting high impregnating ability to the mold on the outside of the coils 41 45, and notches 71, 72 are provided at the upper and lower ends of the swollen part 5, respectively. The fittings 21, 22 are buried vertically in the horizontal section of these notches 71, 72. Thus, the inorganic fiber ribbon bears internal stress created in the molding resin during the molding process. Accordingly, the upper and lower ends of the swollen part 5 can be notched without causing any cracks apt to be generated from the corners and hence the amount of used resin can be economized.

Description

Mold transformer

The present invention relates to as user's user side transformer and the mold transformer that is used in a large number.

In recent years, people begin to be extensive use of the mold transformer with molded windings such as epoxy resin.This mold transformer is compared with oil-immersed type transformer, has low etc. the characteristics of nonflammable, small-sized light weight, noise.

The prior art of this mold transformer such as Fig. 6～shown in Figure 11, wherein, Fig. 6 is that outside winding is the front view of the existing mold transformer of Y connection, and Fig. 7 is its end view, and Fig. 8 is that outside winding is the front view of the existing mold transformer of △ connection.In these figure, 9A unshakable in one's determination is the three-phase iron core, disposes inboard winding and outside winding 1A on the pin unshakable in one's determination of each phase.Because inboard winding is hidden in the winding 1A of the outside, in these figure, do not mark.The support 10A that the securing member of using for these windings of fixed bearing is assembled up and use in the middle of being arranged in upper and lower two places clips the loop iron core.Outside winding draw with terminal fittings 21A, 22A and the equal horizontal direction of tap terminal accessory 3A imbed outside the side of winding 1A, tap terminal accessory 3A divides 2 row up and down, and each 3 arranged side by side, by utilizing tap-change plate 63A to connect in following one selectively, carry out tap-change.Among Fig. 6, Fig. 7, on the terminal fittings 21A of upper end, with screw fastening draw the connector 61A that lead is used for connecting to what drew the outside, and on the terminal fittings 22A of bottom, with screw fastening neutral point connect lead 65A.

Among Fig. 8, connect, the terminal fittings 21A of each phase upper end is connected with the terminal fittings 22A of another bottom mutually with the alternate lead 81A in position, 82A, 83A for outside winding being carried out △.This connection lead is made of flat conductor, and itself has rigidity, by making it in the supported mechanical strength that keeps of some suitable positions.

Fig. 9 is the stereogram of one of outside winding 1A, Figure 10 is the profile of Fig. 6, the section of outside winding 1A is the section that is arranged in along the A-A line of Fig. 9, profile along the A-A line among Fig. 9, in Figure 10, reach the dielectric strength between the terminal fittings between the lead in order to ensure the tap lead extension that is connected usefulness with tap terminal accessory 3A of drawing, between the coil from coil 43A, 44A, carried out molded with resin to this part, so, the resin thickness of this part is higher than other parts, forms protuberance 5A.

Among Figure 10, connector 61A is crooked laterally, thereby guarantees the aerial insulation distance of it and carriage 10A.And forming the insulation breakdown road in order to prevent along resin surface, the creeping discharge beeline must be greater than aerial insulation distance, so, the insulation distance L between connector 61A and the tap-change plate 63A ₁, and tap-change plate 63A is connected the insulation distance L between the reed 65A with neutral point ₂Sufficient length must be arranged, so that the unlikely path that makes this along formation insulation breakdown on the face.

Figure 11 has provided the terminal fittings 21A of upper end and has been anchored on this part detailed structure of wire connector 61A on the 21A with screw, among Figure 11, on the terminal fittings 21A in being embedded in resin protuberance 5A, be screwed connector 61A, when the operations such as installation of the terminal wire that carries out being connected with this connector, connector 61A just can be subjected to active force, and terminal fittings is subjected to turning power, thereby the resin of damage terminal fittings inlet part, prevent revolving member 211A in order not damage the resin of this part, to be provided with, still, in order to ensure the space that this member is set, the position of imbedding of terminal fittings 21A has descended downwards.The situation of the terminal fittings 22A of bottom is also identical therewith.

The protuberance 5A of Fig. 9 as mentioned above, be between the extension in order to ensure the tap lead of drawing from coil 43A and 44A that is connected with tap terminal accessory 3A, reach the dielectric strength that waits between the tap terminal accessory between the coil, molded together and be provided with them, but in fact, except that the middle body of this protuberance 5A, upper part and end portion there is no the necessity that protuberance is set, upper part for example, overlapping laterally coiling forms from the inboard because coil 41A is plate-shaped conductors, so its outside is in same current potential, this outside and terminal fittings 21A, and the current potential of drawing lead of drawing from coil 41A that they are coupled together is all identical, thus needn't insulate with moulded resin, therefore, can consider to remove this part, reduce the thickness of resin so that save resin.But in molding process, from making the resin heat hardening to cooling, moulded resin can produce internal stress because of thermal contraction takes place, and the interior angle part that concentrates on breach because of this stress cracks sometimes, so can not adopt this breach structure.

Again, in Figure 10, L ₁Be the insulation distance between upper connector 61A and the tap-change plate 63A, L ₂Be the insulation distance between tap-change plate 63A and the neutral point connecting line 65A, L ₃Be the insulation distance between upper bracket 10A and connector 61A, the insulation breakdown of this three part directly causes the destruction of mold transformer easily, so the essential insulation distance that fully guarantees them.Insulation distance L ₁, L ₂Be by the decision of the class of insulation of outside winding, so the minimum winding height of outside winding is also determined by their insulation distance.On the one hand, be that capacity with transformer changes as its best winding height of transformer, but under the high-tension situation of low capacity, the height dimension of winding is in fact by this insulation distance L ₁And L ₂Limit, so can only depart from best design of transformer, consequently cause the increase of transformer weight, size, loss and cost etc.Again, because the connector of the terminal of upper end is near support, so in order to obtain required insulation distance, connector is crooked laterally to guarantee insulation distance L ₃, therefore but produced the lateral dimension L of transformer again ₄The shortcoming that increases.

The objective of the invention is to, by crackle does not take place removing the unnecessary resin part of protuberance upper and lower side, obtaining a kind of resin use amount that makes reduces, even under the situation that the insulation distance between, connector high at the capacity small voltage etc. is difficult to guarantee, also can guarantee the transformer device structure of insulation distance with comparalive ease.

In order to address the above problem, for following a kind of mold transformer, promptly, tabular conductor is clipped paper tinsel shape insulating material, the overlapping laterally coil that is wound into from the inboard, it is resin molded that a plurality of such coils are carried out integral body again along the axially-aligned of winding, and in the protuberance of the moulded resin portion of the outside of molded formation winding, imbed the mold transformer that terminal fittings forms, characteristics of the present invention are, the good inorfil band of resin impregnability in the outside package of above-mentioned coil, and the horizontal component of the barbed portion that stays behind the resin perpendicular to the upper and lower end parts of removing above-mentioned protuberance of the terminal fittings of above-mentioned outside winding is imbedded.

In the formation of the present invention, in order to ensure imbedding the tap terminal accessory, tap lead extension from coil, dielectric strength between coil and the tap terminal accessory etc., it is molded to utilize resin to carry out to this part, thereby form the resin protuberance, for save protuberance on, the resin of bottom, remove on this, the projection of bottom, and it is molded by carrying out under the situation of the inorfil band in the outside package of the coil that constitutes outside winding, can make in molding process, the internal stress of the moulded resin that produces when cooling off after the heat hardening is born by the inorfil band, to alleviate the stress concentration phenomenon at breach interior angle place, so can prevent to crack from this interior angle.Also have, utilization is in idiostatic respectively because of coil outer surface, terminal fittings and the lead-out wire of upper and lower side, even so near insulation aspect problem this point can not take place yet, terminal fittings is imbedded from the horizontal plane perpendicular to this breach, thereby strengthened creepage distance between terminal fittings and the tap terminal accessory.

The drawing brief introduction

Fig. 1 is the stereogram of the outside according to an embodiment of the invention winding, Fig. 2 is the winding profile of embodiment, Fig. 3 is the terminal part enlarged drawing of embodiment, Fig. 4 is arrow P direction (bowing) view of Fig. 3, Fig. 5 is that outside winding is the front view according to a kind of three-phase mold transformer of the present invention that △ connects, Fig. 6 is that existing outside winding is the front view of the three-phase mold transformer of Y when connecting, Fig. 7 is the end view of Fig. 6, Fig. 8 is that existing outside winding is the front view of the three-phase mold transformer of △ when connecting, Fig. 9 is the stereogram of existing outside winding, Figure 10 is the profile of Fig. 9, and Figure 11 is the terminal part enlarged drawing of prior art.

Among the figure, 1 ... outside winding, 21,22 ... terminal fittings, 3 ... the tap terminal accessory, 41,42,43,44,45 ... coil, 46,46A ... inboard winding, 5 ... protuberance, 61 ... connector, 63 ... the tap-change plate, 65 ... neutral point connects reed, 71,72 ... barbed portion, 73 ... the interior angle part, 9 ... unshakable in one's determination.

Followingly the present invention is described according to embodiment.The protuberance 5 of outside winding 1 as shown in Figure 1, the end is provided with the barbed portion 71 of doing excision from the resin upper end of the winding of outside winding 1 thereon, is provided with the barbed portion 72 of doing excision from the resin bottom of winding in its bottom.

Fig. 2 constitutes according to the present invention, the out conductor group is the profile of the mold transformer of Y connection, and the cross-section illustration of its outside winding 1 comprises the section along B-B line among Fig. 1 of the protuberance 5 of Fig. 1.As shown in the drawing, on the coil 41～45, package has the glass fabric 11 as the well behaved inorfil band of resin impregnated, and this glass fabric 11 works to strengthen the mechanical strength of coil 41～45 simultaneously.Resin molded by carrying out under the state of this glass fabric 11 in package, the internal stress that the thermal contraction that takes place when making because of the cooling after heat hardening produces is born by this glass fabric 11, the phenomenon that stress concentrates on interior angle part 73 is alleviated, thereby can prevent to produce the crackle that causes because of this interior angle part 73.Terminal fittings 21 is imbedded from the horizontal plane direction perpendicular to barbed portion 71, again connector 61 usefulness screws are fastenedly connected on terminal fittings 21, terminal fittings 22 is imbedded from the horizontal plane direction perpendicular to barbed portion 72, again neutral point is connected lead 65 usefulness screws and be fastenedly connected on terminal fittings 22.

When connector 61 screws when fastening, because the part of the force of connector 61 is horizontal, so fastening direction is the direction away from support 10, therefore, being guaranteed space insulation distance essential between them more simply by terminal fittings 21.Again as shown in Figure 3, Figure 4, be close to by end one side and the vertical plane of barbed portion that makes connector 61 relative, the effect that this part is played prevent connector 61 from rotating, thus can save as shown in figure 11 prevent to rotate accessory 211A.In addition, be eased, preferably the interior angle part 73 of Fig. 3 be processed into the shape on curved surface or inclined plane for stress is concentrated.

Prior art prevents to rotate accessory 211A in order to be provided with, the position of terminal fittings 21A structurally is restricted, this is a shortcoming, but according to the present invention, the installation position of terminal fittings 21 is the distance of the upper end resin face of the face of breach 71 and coil 41 among Fig. 2, can after considering and being positioned at the relative position relation of the terminal fittings 21 of 63 of support 10 and tap-change plates and connector 61, select the optimum size of insulation aspect.More than be the explanation about the upper end, the structure and the upper end of bottom are similar.

When outside winding is the △ connection, as shown in Figure 5, the alternate lead in position that the terminal fittings of the bottom of the upper end of each phase winding and another phase winding is coupled together adopts the covered wire energy free bend, that the process insulation coats, by this covered wire is contacted with the evagination angle part of barbed portion, and carry out alternate connection under the tension force situation having, can fix its position just supporting that can need not be other as this alternate covered wire 81,82 is fixing.Just, connect the alternate covered wire 83 of two phases in two outsides, because the winding of phase is provided with in the middle of must avoiding, so must fix at 2 positions with supporting member 801,802.

The present invention can obtain following effect: as previously mentioned, by the good inorfil matter band of resin impregnability in the outside package of the coil that consists of outside winding, can cut partial tree fat section not producing in the situation of the interior angle crackle partly of the upper and lower end of protuberance, so can save the resin of this part. Again because by terminal fittings is imbedded in the horizontal plane of this barbed portion, insulation distance between support or tap-change plate and the connector can be guaranteed, so, especially concerning the mold transformer of low capacity, because it is bigger that the insulation distance between these accessories can be obtained, so the winding height dimension that this insulation distance of reason determines causes the situation of the increases such as transformer weight, size and loss with rare greater than the optimal design size of transformer. In addition, when outside winding is △ when connecting, the alternate lead by alternate connection usefulness adopts the covered wire that bendability is arranged and carried out insulating wrapped, the variable convenience of the making of lead and assembling work, etc.

Claims (1)

1, a kind of mold transformer, be to accompany the tabular conductor of paper tinsel shape insulating material along the axially-aligned of the winding coil that overlapping laterally coiling forms from the inboard in the outside by using by coil with a plurality of, the inorfil band good on the coiling of the outside of this coil to the resin wettability, it is resin molded that it is all carried out, and embed the metal terminal member at resin molded projection, it is characterized in that respectively forming notch part, the metal terminal member of outside winding is vertically embedded in the horizontal component of this notch part in the upper and lower end of resin molded protuberance.

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