JPS61181113A - Manufacture of transformer - Google Patents

Abstract

PURPOSE:To realize the annealing to an inner iron type iron core consisting of amorphous magnetic alloy thin belt under the condition that a transformer coil is loaded by dividing a rolled iron core or laminated iron core into two sections, loading a transformer coil in common to respective magnetic paths, loading individually a temporarily wound coil and applying a high frequency current. CONSTITUTION:Width of rolled iron core formed by winding an amorphous magnetic alloy thin belt 1 is divided into two sections in order to form a rolled iron core 2, a transformer coil 3 is wound to each leg part bridging over the respective rolled iron core 2, a temporary coil 4 is wound individually to the upper yoke and is con nected in the reverse polarity and a frequency current is applied in the direction of arrow mark from a high frequency AC power supply 5 for excitation. Thereby, mag netic flux of a current flowing into the rolled core 2 is inversed as indicated in the figure. Therefore, the magnetic fluxes crossing the transformer coil 2 are inversed, cancelling each other, but not generating induced voltage due to the high frequency magnetic flux. The rolled core 2 is held through temperature rise by the heat generated therefrom with a high frequency excitation. Thereafter, a temporary coil 4 is then connected to the DC power supply and the iron core is cooled while a DC magnetic field is being applied.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a transformer in which an iron core made of an amorphous magnetic alloy ribbon is annealed.

[Technical background of the invention and its problems] Recently, it has been considered to form an iron core used in a transformer using an amorphous magnetic alloy ribbon. This material is manufactured by rapidly cooling magnetic alloy WJ hot water, so it has excellent magnetic properties with very low iron loss. When manufacturing a transformer using an iron core made of this amorphous magnetic alloy ribbon, it has been considered to use a one-piece cut-shaped wound core, since this makes it easier to assemble the transformer coils attached to the iron core. ing.

This is a method of forming a wound core by inserting amorphous magnetic alloy ribbons for each turn into a transformer coil.

On the other hand, amorphous magnetic alloy ribbons are highly sensitive to stress and their magnetic properties are degraded by the strain that occurs during production, so when producing the wound core, they are subjected to strain relief annealing to restore their magnetic properties. Further, since the amorphous magnetic alloy ribbon becomes brittle and easily damaged after annealing, it is necessary to avoid processing after annealing to prevent damage. Recently, a method has been devised in which a temporary coil is attached to an iron core made of an amorphous magnetic alloy ribbon along with a transformer coil, and the temporary winding coil is used to excite the iron core at high frequency to generate self-heating and perform annealing. ing. According to this method, there is little thermal influence on the transformer coil, and C annealing can be performed with the core made of amorphous magnetic alloy ribbon incorporated into the transformer coil, thereby avoiding post-annealing processing. It becomes possible to use a one-turn cut type wound core. However, in such a high-frequency excitation annealing method, when a high-frequency current is passed through the pre-wound coil, the voltage E induced in the winding is EO': fB (f...frequency,
B...magnetic flux density), and if it is 1 at the commercial frequency
゜For a transformer designed with 3T, 50Hz, 5KH2,
When excited at 1.0K, this occurs, resulting in dielectric breakdown in the transformer coil.

Therefore, in the case of an outer iron core structure, two wound cores 2 and 2 are formed by winding amorphous magnetic alloy ribbon 1, as shown in Part 2.
A transformer coil 3 is arranged on the central leg of the coil 2.2, a temporary winding coil 4.4 is connected to the upper yoke of each winding core 2.2 with opposite polarity, and a high frequency power source 5 is connected to the temporary winding coil 4.4. If a high frequency current is sent in the direction of the arrow to excite the wound core 2.2,
The directions of the magnetic fluxes in the central leg of 2.2 are opposite to each other, and no induced voltage is generated by the high-frequency magnetic flux in the transformer coil 3 wound in advance across the central leg.

However, since the inner iron core has only one magnetic path, there is a problem in that it is not possible to arrange temporary winding coils of opposite polarity.

[Object of the Invention] The present invention has been made based on the above circumstances, and is capable of annealing an inner iron core made of an amorphous magnetic alloy ribbon with a transformer coil attached. It is an object of the present invention to provide a method for manufacturing a transformer that can reduce the number of subsequent post-processes.

[Summary of the Invention] The method for manufacturing a transformer of the present invention involves forming a magnetic path in a core made of amorphous magnetic alloy ribbon in the width direction in the case of a wound core structure and in the thickness direction in the case of a stacked core structure. It is divided into two parts, a common transformer coil is attached to each magnetic path, and a pre-wound coil is attached to each individual, and the pre-wound coils are connected with opposite polarity so that the total magnetic flux of the core is zero, and the current for high-frequency excitation is generated. The iron core is energized by energizing it, and the loss that occurs in the iron core due to this excitation causes the core itself to generate heat and heat up, thereby annealing it.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to drawings. As shown in FIG. 1, the width of the wound core around which the amorphous magnetic alloy ribbon 1 is wound is divided into two to form a wound core 2.2, and each wound core 2.2 is divided into two.
2, a transformer coil 3.3 is wound around each leg, and falsely wound coils 4.4 are individually wound around the upper yoke and connected to each other in opposite polarity. If a high frequency current is applied from the high frequency AC power source 5 in the direction of the arrow to excite the core 2.2, the direction of the magnetic flux flowing through the wound core 2.2 will be as shown in the figure @0.
The direction is the opposite, as in Therefore, the magnetic fluxes interlinking with the transformer coil 4, which has been previously wound across the wound core 2.2, are in opposite directions and cancel each other out, so that no induced voltage is generated due to the high-frequency magnetic flux. In this case, the number of turns or high-frequency current value of the temporary winding coil 4.4 is adjusted so that the amount of magnetic flux flowing through each wound core 2.2 is the same.

Then, by high-frequency excitation, the temperature of the wound core 2.2 is raised to about 400° C. by its own heat generation, and this temperature is maintained for about 1 hour. Then, the temporarily wound coil 4.4 is switched to a DC power source (not shown), and the wound core 2.2 is cooled while applying a DC magnetic field.

In this way, the inner iron core can be used in the same way as the outer iron core.
High-frequency excitation annealing is possible with the transformer coil wound, and the iron core can be annealed without damaging the insulation of the transformer coil.

In addition, even if the amorphous magnetic alloy is in a embrittled state after annealing, the process of assembling the transformer coil into the iron core can be carried out, reducing the stress applied to the iron core after annealing, and making the amorphous magnetic alloy thinner. Damage such as cracking and splintering of the belt can be prevented.

Although FIG. 1 shows a wound core, the same effect can be obtained with a laminated core structure by dividing the core into two in the stacking thickness direction and placing a pre-wound coil in each magnetic path based on the same principle.

[Effects of the Invention] As explained above, according to the transformer manufacturing method of the present invention, even in the case of an inner iron core, the number of assembly steps after core annealing can be reduced, and damage due to embrittlement of the amorphous magnetic alloy ribbon can be reduced. It can be manufactured using an iron core with excellent magnetic properties that can prevent

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a method of manufacturing a transformer according to the present invention;
FIG. 2 is a front view showing the previously proposed method for manufacturing a transformer. 1...Amorphous magnetic alloy ribbon, 2...Wound iron core, 3...
・Transformer coil, 4... temporary winding coil, 5... high frequency AC power supply. (7317) Agent Patent Attorney Kensuke Norichika (and 1 other person) Figure 1 Figure 2121

Claims (1)

[Claims] A wound core made of amorphous magnetic alloy ribbon is divided into two in the width direction or the thickness direction to form two magnetic paths, and a transformer coil is commonly attached to each magnetic path, and a transformer coil is installed individually in each magnetic path. Manufacture of a transformer by attaching a pre-wound coil to the coil, and applying a high-frequency current to the pre-wound coil while connecting the pre-wound coils with opposite polarities to generate heat in the iron core itself due to the loss generated in each of the magnetic paths and annealing it. Method.