JPH0222976Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to an improved structure of an external iron type transformer, particularly its winding tightening device.

[Conventional technology]

When a ground fault or short circuit occurs in a power system, an overcurrent flows through the transformer windings, generating electromagnetic force in the windings. This situation in a conventional transformer is shown in FIGS. 4a and 4b. FIG. 4a shows a longitudinal section of the external iron type transformer, and FIG. 1b shows its cross section. In the figure, 1 is a tank, 2 is an iron core, 31 to 34 are low-voltage windings, 41 and 42 are high-voltage windings, 5 is an insulator inserted between each winding, and 61 and 62 are tightened and fixed insulators. It is a wedge. 71 and 72 are the currents flowing in the low voltage windings 31 to 34 and the high voltage windings 41 and 42, respectively, and their directions; 81 is the magnetic field generated by the winding currents and its direction; 91 and 92 are the winding currents and the field shows the electromagnetic force and direction generated by the action of

FIG. 5 shows the winding current flowing during an accident and the time waveform of the electromagnetic force generated. When the electromagnetic forces shown at 91 and 92 in FIG. 4 are generated by the electromagnetic force shown in FIG.
2 may collide with the insulator 5, causing damage to both. Therefore, it was necessary to firmly tighten the winding and the insulator to prevent movement. For this reason, conventionally, devices having the above-mentioned structure were assembled using the following procedure.

First, 31 to 3 were sufficiently dried and shrunk.
A coil group consisting of 4, 41, 42 and 5 is erected in the lower tank 11 as shown in FIG.
Drive in wedge 61. Next, as shown in Figure 7, the iron core 2
Stack up. At this time, the coil group is stacked while being tightened with the iron core 2. Next, as shown in FIG. 8, the middle tank 12 is attached and a wedge 62 is driven in.

[Problem that the invention attempts to solve]

Although the coil group can be firmly tightened using the conventional means and procedures described above, the above procedure not only stacks the iron core, but also has the disadvantage that it takes a lot of time because the iron core is stacked while tightening the coil group.

This invention was made to eliminate these drawbacks, and aims to improve workability and strengthen the tightening force in the axial direction of the winding.

[Means for solving problems]

In this invention, a wedge made of an insulating material is provided between the coils of the coil group in a transformer that uses one or more unit coils on an outer iron core to form a coil group. It is.

[Effect]

In this way, by driving a wedge made of an insulating material between the coils, it is possible to tighten the coils in the axial direction, so there is no need to tighten the coils with the iron core during core stacking work, which facilitates the work.

〔Example〕

1 to 3 show the structure and assembly procedure of one embodiment of this invention. In the figure, 63, 64, and 65 are wedges used in this invention, and the other configurations are the same as those of the conventional one, so the same reference numerals are given and the explanation will be omitted.

In assembling, first, as shown in Figure 1, 3
A coil group consisting of 1 to 34, 41, 42, and 5 is erected in the lower tank 11, and a wedge 61 similar to the conventional one is driven in. At the same time, a wedge 63 according to this invention is inserted.
is inserted between the coils 41 and 32. Next, as shown in FIG. 2, a wedge 64 is driven in after the core has been laid. In this case, the part surrounded by the iron core 2 is tightened using the wedge 64.
, so the iron cores 2 only need to be piled up. Next, as shown in FIG. 3, the middle tank 12 is installed, and the conventional wedge 62 is driven in, as well as the wedge 65 of this invention.

In this way, this invention not only greatly improves the core stacking work, but also enables stronger tightening of the coil group. Furthermore, wedge 6 of this idea
Since 3, 64, and 65 are made of an insulator, they form part of the insulation originally required between the high voltage coil and the low voltage coil. Therefore, no additional dimensions are required by providing these wedges.

[Effect of idea]

As described above, according to this invention, it is possible to facilitate the work of assembling the core of an external iron transformer, increase the axial tightening force of the coil group, and improve the strength of the coil against short-circuit electromagnetic force.

[Brief explanation of the drawing]

1 to 3 are front sectional views showing the structure and assembly procedure of an embodiment of this invention, FIG. 4 shows a conventional outside iron type transformer, and a is a front sectional view;
b is a sectional view taken along line A-A in Fig. 4a, Fig. 5 is a diagram explaining the relationship between the coil current and electromagnetic force of the transformer, and Figs. 6 to 8 are the same as shown in Fig. 4. It is a figure which shows an assembly procedure. In the figure, 1 is a tank, 1a is a lower tank, 1b is a middle tank, 2 is an iron core, 31 to 34 are low voltage coils, 41 and 42 are high voltage coils, 5 is an insulator, 61
65 are wedges. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] A transformer comprising a combination of coil groups formed by using one or more unit coils in an outer iron core, characterized in that a wedge made of an insulating material is provided between the coils of the coil group. Outside iron transformer.