JPS639355B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotating magnetic field type electromagnetic stirring device, and particularly to an improvement in the induction coil housing portion thereof.

2. Description of the Related Art It is generally known that the quality of a casting can be improved by stirring the molten metal in the mold when producing a casting.

Since the mold to be stirred is usually square or rectangular in shape, an electromagnetic induction coil is placed around the mold in a rectangular shape along the shape of the mold, and three-phase alternating current is applied to it. This generates a rotating magnetic field and stirs the molten metal through electromagnetic induction between the molten metal and the molten metal.

FIG. 1 shows the configuration of an iron core of a conventional device for performing such stirring. That is, in this figure, 1 is an iron core for constructing an electromagnetic device for stirring molten metal, and 2 is a rectangular hole formed in the center of the iron core, which is inserted into a mold (not shown). This forms an electromagnetic stirring device around the mold.

3 to 8 are slots for mounting an electromagnetic induction coil formed in the iron core along the square hole;
Six slots of the same shape and width and depth are formed on each side.

Note that 3 and 4 of the 6 slots on each side are U
Phases 5 and 6 are V-phase coils, and 7 and 8 are W-phase coils.

FIG. 2 shows the state of the coil ends when the coils of each phase are installed in such slots, and is a view of the iron core 1 of FIG. 1 viewed from a direction parallel to the plane of the paper. In this figure, 9 is the U-phase coil,
One coil side 9A is attached to the above slot 3, and the other coil side 9B is attached to the above slot 4. 10 is a V-phase coil, and one coil side 10A is installed in the slot 5, and the other coil side 10B is installed in the slot 6. Also,
11 is a W-phase coil, one coil side 11A is installed in the slot 7, and the other coil side 11B is installed in the slot 8.

In such a configuration, the leftmost coil side 9A in the figure among the coils 9 and 11 located at both ends of each side has the rightmost coil side 11B of the W phase on the other side, and the right side Since the distance from the coil side 9B located at the coil end is different, the leakage reactance at the coil end (portion located outside the core) is smaller than that at the other coil sides.

In addition, the coil side 11 located on the rightmost side of each side
The same applies to B. Other coil sides are
Since the distances to the coil sides located on both sides of each coil are equal, the leakage reactance at the coil end is larger than that at the endmost coil side.

As a result, the leakage reactance of the U-phase and W-phase coils 9 and 11 becomes smaller than that of the V-phase coil 10, creating an impedance imbalance, which has the disadvantage that the power supply capacity must be increased accordingly. be.

This invention has been made to eliminate these drawbacks, and provides an electromagnetic stirring device in which the shape of slots formed on each side of a square hole formed in the center of an iron core is changed. be.

An embodiment of the present invention shown in FIGS. 3 and 4 will be described below.

FIG. 3 shows the configuration of the iron core and corresponds to FIG. 1 of the conventional device. In this figure, 1
2 and 13 are slots for installing the U-phase coil, 1
4 and 15 are also for the V phase, and 16 and 17 are for the W phase, and as is clear from the figure, the slots 12, 13 and 16, 17 located at both ends are longer and narrower than the slots 14, 15 located at the center. It is characterized by the point where it is formed. FIG. 4 is an enlarged view showing the state in which the coils are installed in the slots on each side, and 18 indicates the wedge of the slot. With such a configuration, the coils 9A and 9B located at both ends of each side
Since the leakage reactance of coils 11A and 11B is larger than that of coils 10A and 10B located in the center, it is possible to balance the leakage reactance of each phase of the three-phase coil, and therefore the impedance of each phase, by that much. This makes it possible to reduce the power supply capacity.

In addition, in the above embodiment, an example was shown in which the coils were concentrated windings and one coil was arranged for each phase, but each phase coil was formed from several coils, and phase coil groups located at both ends were used. A similar effect can be expected when the slots are made longer and narrower than the slots of the phase coil group located at the center. moreover,
Even if the square shape of the central part of the core is a rectangle and the numbers of poles arranged on the long and short sides are different, the same implementation is possible.

[Brief explanation of the drawing]

1 and 2 show a conventional device, with FIG. 1 showing the structure of the iron core, and FIG. 2 showing the structure of the coil end portion of the coil installed in each slot. Figures 3 and 4 show an embodiment of the present invention. Figure 3 is a diagram showing the configuration of the iron core, and Figure 4 is an enlarged view showing the state in which the coils are installed in the slots on each side. . In the figure, 1 is the iron core, 2 is a square hole, 12-1
7 is a slot, and 9 to 11 are coils. In addition,
The same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1. An electromagnetic induction coil is arranged in a rectangular shape around the mold, and this coil is energized by a multiphase AC power source to form a rotating magnetic field, and the molten metal in the mold is Of the multiple slots for storing electromagnetic induction coils arranged on each side of a rectangular shape in a stirring device, the slots located at both ends are made longer and narrower than the slots located in the middle. Characteristic rotating magnetic field type electromagnetic stirring device. 2. The rotating magnetic field type electromagnetic stirring device according to claim 1, wherein the multiphase AC power source is a three-phase AC power source. 3. The rotating magnetic field type electromagnetic stirring device according to claim 1 or 2, wherein the rectangular shape is a square. 4. The rotating magnetic field type electromagnetic stirring device according to claim 1 or 2, wherein the square shape is a rectangle.