JPH023614Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a magnetic shielding device installed in a tank of an induction electric device such as a transformer reactor.

For example, in transformers and the like, when the capacity increases, leakage magnetic flux from the windings increases, which increases eddy current loss in the tank wall, so a structure with a magnetic shield as shown in FIG. 1 is adopted. That is, magnetic shield plates 11, which are made of laminated thin magnetic plates such as electric iron plates, are attached to the inner wall surface of a tank 3 containing an iron core 1 and a winding 2, arranged horizontally with their longitudinal directions perpendicular to each other. This forms a magnetic path for the leakage magnetic flux as shown by the arrow, and prevents the magnetic flux from entering the tank wall.

However, as shown in the right half of the figure, if the tank has a large pocket hole 5 through which the lead wire 4 is passed, the second
As shown in the figure, short magnetic shield plates 12 cut along the holes are installed horizontally in the upper and lower parts, and long magnetic shield plates 11 extending upward and downward from the pocket holes are installed at the ends of the arrangement.
are arranged horizontally.

In such a structure, when leakage magnetic flux with the distribution shown in FIG. 3 enters the short magnetic shield 12 cut at the top and bottom of the pocket hole, the magnetic flux passing through the shield plate passes through the tank wall near the cut part and is transferred to the adjacent magnetic shield. It flows into the plate or along pocket holes in the tank wall and into the cut magnetic shield underneath. Therefore, eddy current flows in the tank wall near the pocket hole, and overheating of the tank wall is unavoidable due to the eddy current loss.

The present invention has been developed in view of the above points, and an object of the present invention is to provide an induction electric magnetic shielding device that can effectively prevent leakage magnetic flux from entering the tank wall near the pocket hole.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 4 shows a magnetic shielding device of the present invention corresponding to FIG. 2, and its structure is the same as that shown in FIG. A plurality of strip-shaped magnetic shielding plates 112 formed by stacking the magnetic shielding plates 112 are arranged horizontally in a plurality of rows with their longitudinal directions perpendicular, and a long strip-shaped magnetic shielding plate is attached at each end of the arrangement of the upper and lower magnetic shielding plates 112. 111 are arranged in multiple rows in the lateral direction, and as shown in FIG. 5, each of the magnetic shield plates 111 and 112 has a stepped portion 113 formed in two step-like steps on both sides in the plate width direction.
The point superimposed and magnetically coupled to the step of the magnetic shield plate adjacent to this step 113 is the second point.
It is different from the one shown.

With this configuration, the magnetic shield plate 11
1 and 112 have much higher magnetic permeability than the tank wall, and the magnetic shield plates are magnetically coupled in the upper arrangement direction, so even if the magnetic shield plates are interrupted at the pocket hole 5, leakage magnetic flux will invade the tank wall. It flows in the direction of the arrow (shown) through the magnetic shield plates that are connected without any interference. Therefore, leakage magnetic flux does not enter the tank wall 3, eddy current loss is prevented, and there is no fear of local overheating.

In the embodiment shown in FIG. 5, magnetic shields 111 and 112 are arranged on a flat tank wall, but as shown in FIG. 112 may also be provided. In this case, the connection between the stepped portions 113 is a line contact, and the connection performance is somewhat reduced, but practically the effect is substantially the same as that of the above embodiment.

In addition, as shown in FIG. 7, the magnetic shield plate 11
The 1,112 step portions 113 may each be made into three or more steps to further improve the connectivity.

As described above, according to the present invention, by magnetically coupling the arranged magnetic shield plates with each other through the stepped portions, leakage magnetic flux is prevented from entering the tank wall at the pocket hole portion, and the leakage magnetic flux is prevented from entering the tank wall at the pocket hole portion. A magnetic shielding device that is free from overheating can be provided.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional induction electric appliance with a magnetic shielding device installed on the tank, Fig. 2 is a view taken from Fig. 1 along the line, and Fig. 3 is a distribution diagram of leakage magnetic flux incident on the magnetic shield plate. FIG. 4 is a magnetic shield plate arrangement diagram showing one embodiment of the magnetic shielding device of the inventive induction appliance corresponding to FIG. 2, FIG. 5 is a sectional view taken along the line of FIG. 4, and FIG. FIG. 7 is a sectional view showing still another embodiment of the present invention. 3...Tank, 5...Pocket hole, 111,1
12...Magnetic shield plate, 113...Stepped portion.

Claims (1)

[Scope of utility model registration request] A plurality of strip-shaped magnetic shield plates are provided horizontally in multiple rows extending perpendicularly to the upper and lower parts of the pocket hole on the inner surface of the tank side wall in which the lead wire pocket hole is provided, and vertical strips are provided following the array ends of the upper and lower magnetic shield plates. In a device in which a plurality of long strip-shaped magnetic shielding plates that are continuous in the horizontal direction are provided in a plurality of rows in the horizontal direction, each of the magnetic shielding plates has a stepped portion formed in at least two step-like steps at both ends in the width direction of the plate. 1. A magnetic shielding device for an induction electric appliance, characterized in that the stepped portion is overlapped with the stepped portion of an adjacent magnetic shielding plate and magnetically coupled to the stepped portion.