JPH0134334Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to multiple cylindrical windings with improved end reinforcement insulation.

[Technical background of the invention and its problems]

In recent years, multiple cylindrical windings have been increasingly used in windings ranging from small capacity to relatively large capacity transformers. Multiple cylindrical windings are constructed by arranging cylindrical windings in which conductive wire is wound into a cylindrical shape in multiple layers in the radial direction, and end reinforcing insulators are inserted into both axial ends of each cylindrical winding to strengthen the electric field. We are trying to reduce concentration and reduce insulation dimensions.

That is, as shown in FIG. 1, a cylindrical winding 2 is constructed by winding a conductor 2a in a cylindrical shape on an insulating cylinder 1, and several turns of the conductor 2a are formed at both axial ends of each cylindrical winding 2. An end reinforcing insulator 4 is placed across the end. Note that the cooling duct 3 is formed by inserting duct pieces at intervals in the circumferential direction. Further, an end filling 5 is provided on the axially outer side of the end reinforcing insulator 4.

The end reinforcing insulator 4 is inserted along the circumferential direction of the cylindrical winding 2, and the outer circumferential side thereof is longer in the circumferential direction than the inner circumferential side, so that at least the outer circumferential side has elasticity. There is a need. In addition, when winding the wire, the end reinforcing insulator 4 is placed with its opening side open, and after the conductor 2a is wound, it is returned to the U-shape. It is also necessary to provide elasticity on the outer circumferential side.

Therefore, this edge reinforcing insulator 4 is made by stacking multiple sheets of stretchable crepe paper and bonding them together under pressure with an adhesive that does not impair the stretchability of the crepe paper to form a U-shape. I am using it.

However, in this case, the end reinforcing insulator 4 also has elasticity on the inner circumferential side, so if there is a cooling duct 3 inside the cylindrical winding 2 as shown in FIG. The inner circumferential side of the end reinforcing insulator 4 swells in the portions that are not covered, and enters the cooling duct 3, which significantly obstructs the flow of insulating oil rising inside the cooling duct 3, thereby deteriorating the cooling effect.

[Purpose of invention]

The present invention has been made in order to eliminate the above-mentioned drawbacks, and it is an object of the present invention to provide a multiple cylindrical winding having end reinforcing insulation that does not impair the cooling effect of the insulating oil.

[Summary of the idea]

In order to achieve this object, the present invention covers both axial ends of the cylindrical winding wire in an end insulator formed by press-bonding multiple sheets of crepe paper and having a U-shaped cross section. By attaching relatively hard insulating paper such as pressboard or parchment paper to crepe paper and bonding it together with pressure only on the axial portion located on the inner circumferential side, the axial portion is prevented from swelling and deforming. This prevents the flow of insulating oil rising inside the cooling duct from being obstructed.

[Example of idea]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 2, cylindrical windings 2 in which a conductor 2a is wound in a cylindrical shape are arranged in multiple layers in the radial direction on an insulating cylinder 1 via a cooling duct 3, and both axial ends of each cylindrical winding 2 ( In the figure, only the upper end is shown), multiple sheets of crepe paper are bonded under pressure, and an end reinforcing insulator 6 formed into a U-shape in cross section is placed over several turns of the conductor 2a, and the outer side in the axial direction is An end filling 5 is provided at the end. As shown in FIG. 3, the end reinforcing insulator 6 has an axial portion 6a located on the inner periphery, which is made by interposing a relatively hard insulating paper 8 such as pressboard or parchment paper inside a plurality of stacked crepe papers 7. The other parts are formed only from a plurality of stacked crepe papers 7, each of which is bonded under pressure so that the overall thickness is almost uniform. In this case, the length of the hard insulating paper 8 is made slightly shorter than the total length of the axial portion 6a, and the upper end (or lower end) is not located at the bend (corner) from the axial portion 6a to another portion. The crepe paper 7 is prevented from being damaged by bending. Further, the axial portion 6a in which the hard insulating paper 9 is interposed is pressed with a particularly large pressure to be bonded and integrated, thereby increasing the rigidity. Note that the pressure bonding of the plurality of sheets of crepe paper 7 and the like is performed using an adhesive that does not impair the elasticity of the crepe paper 7. The end insulator 6 is attached by winding a pressure-bonded flat crepe paper 7 on the insulating tube 1 or the duct piece, and winding the conductor 2a on the axial portion 6a of the pressure-bonded crepe paper 7. This is done by bending the portion located above the axial portion 6a toward the outer periphery.

In this way, since the axial portion 6a of the end reinforcing insulator 6 has high rigidity, the portion that does not come into contact with a duct piece (not shown) will not bulge and deform, and will not enter the cooling duct 3.
Therefore, the end reinforcing insulator 6 no longer obstructs the flow of the insulating oil rising inside the cooling duct 3, and the cooling effect of the insulating oil is not impaired. In addition, the hard insulating paper 8 is provided only in the axial portion 6a, and even if it is bent at the upper end of the axial portion 6a, the multiple sheets of crepe paper 7 will not be damaged by tearing. without impairing insulation reliability. Moreover, even when inserting the end reinforcing insulator 6 during winding work, the end reinforcing insulator 6 is stretchable except for the axial portion 6a, so the opening side is held in an expanded state. Since the winding work can be carried out using the wire and then the wire can be bent into a U-shape, the winding workability is not impaired. In this case, since the outer circumferential portion of the end reinforcing insulator 6 is provided under tension, there is no outward bulge deformation and there is no need to provide hard insulating paper on this portion.

Although the above embodiment describes the case where the hard insulating paper 8 is interposed in the crepe paper 7, the same effect can be obtained even if it is provided only on the inner circumference side or the outer circumference side of the crepe paper 7 in the axial portion 6a. .

[Effect of idea]

As explained above, according to the present invention, the axial part of the end reinforcement insulator is formed by combining crepe paper and hard insulating paper, and the other part is formed only by crepe paper, so that the end reinforcement It is possible to provide a multi-layered cylindrical winding that can prevent the insulating material from expanding and deforming, thereby preventing the cooling effect of the insulating oil from deteriorating.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the upper part of a conventional multiple cylindrical winding, FIG. 2 is a sectional view showing the upper part of a multiple cylindrical winding according to an embodiment of the present invention, and FIG. 3 is a sectional view showing the upper part of a multiple cylindrical winding according to the present invention. FIG. 2 is a partially cross-sectional perspective view of an end-reinforcing insulator used in the present invention. 2... Cylindrical winding, 2a... Conductor, 3... Cooling duct, 5... End filling, 6... End reinforcing insulator,
6a... Axial portion, 7... Crepe paper, 8...
hard insulating paper.

Claims (1)

[Scope of utility model registration request] Cylindrical windings are arranged in multiple layers in the radial direction, and end reinforcing insulators are placed on both ends of each cylindrical winding in the axial direction by overlapping and bonding multiple sheets of crepe paper under pressure to form a U-shaped cross section. In the multi-layered cylindrical winding, the end reinforcement reinforcing insulator has a hard insulating paper only in the axial portion located on the inner peripheral side of the cylindrical winding.