JPS60263413A - Arc welder - Google Patents

Abstract

PURPOSE:To reduce weight of an iron core by using an amorphous metal magnetic mateial for the iron core of an insulating transformer for welding, determining the value of frequency (f) satisfying the specific relation, and the weight of the iron core to be less than a half of a rated input. CONSTITUTION:A frequency conversion circuit 6 is provided at linear side of the insulating transformer 2 for welding, which is supplied with a power source of a cycle (f)Hz higher than a commercial cycle (f0)Hz. The amorphous metal magnetic material can be used for the iron core in this kind of the arc welder. In case of setting an iron loss (w/kg) value at frequency (f0) and (f) to be Pio and Pi when a flux density of the amorphous metal magnetic material is fixed, the value of frequency (f) is determined to be (Pi/Pio)/(f/f0)<=1. Besides, the relation between a weight Akg of the iron core of the insulating transformer 2 for welding and a rated input capacity BkVA becomes A<=B/2.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an arc welding machine that can be economically designed and manufactured with the aim of reducing size and weight.

(Configuration of conventional example and its problems) As shown in FIG. 1, a conventional arc welding machine is equipped with a commercial frequency power input terminal 11, a welding isolation transformer 2, a rectifier 3, a reactor 4, an output terminal 5, etc. In most cases, a commercial frequency power source is applied to the welding isolation transformer 2, and therefore, in this case, the welding isolation transformer 2
The one designed at the commercial frequency r 9 ) is used.

By the way, recently, as shown in Fig. 2, a frequency conversion circuit 6 has been connected to the primary side of the welding insulation transformer 2, and a power source with a frequency higher than the commercial frequency is supplied to the primary side of the welding insulation transformer 2. Arc welding machines with this type of technology have begun to be manufactured.

When a high frequency power source is supplied to the primary side of the welding isolation transformer 2 through the frequency conversion circuit 6 as shown in FIG.
The electromotive force E of the transformer 2 is determined by the following theoretical formula (% formula % (1)). Assuming that the number of turns N and the magnetic flux density Bm are constant, the cross-sectional area S of the iron core can be reduced in proportion to the frequency f. can. Therefore, by supplying high-frequency power to the primary side of the welding isolation transformer 2 using a frequency conversion circuit, there is an advantage that the welding isolation transformer 2 can be made smaller and lighter. This method has also come to be used in arc welding machines.

However, most of the magnetic materials for the iron cores used in such welding transformers have conventionally been made from silicon steel plates.

Therefore, magnetic materials made of silicon steel plates have problems with iron loss, and there are limits to how small and lightweight welding insulating transformers can be made.

That is, generally, the iron loss of a silicon steel plate is calculated by the following formula.

P, = Ph+ P8 (w/kg) ・・・・・・(
2) f 1゛6 ・・・・・・(3) Ph=σ5・■・Bm(W/kg) p, =σe(t' 100 ”f・Bm)2(WAg
)...(4) (Pl: iron loss, ph: hysteresis loss, P8: eddy current product, σ5・σ. is a constant depending on the material, f
;frequency.

t: Thickness of the iron core, kf: Waveform ratio 'Bm: Maximum magnetic flux density) From the above equation (4), the eddy current product Pe is proportional to the square of the frequency, so the higher the frequency, the smaller the eddy current product Pe. increases. In addition, since the hysteresis loss is proportional to the frequency, the higher the frequency, the hysteresis loss P,
Therefore, from equation (2), the iron loss Pi increases as the frequency becomes higher. For this reason, with conventional magnetic materials made of silicon steel plates, even if the frequency is increased, the cross-sectional area of the iron core cannot be reduced based on equation (1). Therefore, in the circuit configuration shown in FIG. 2, the advantage of the method of supplying a high power frequency to the welding isolation transformer using the frequency converter cannot be utilized. In addition, if the number of turns is increased in order to lower the magnetic flux density, the amount of winding wire used will increase, which will increase costs and increase the number of winding man-hours.
There was a drawback that inexpensive insulating transformers for welding could not be supplied.

(Object of the Invention) The present invention solves the above-mentioned conventional drawbacks, and provides an arc welding insulation transformer that is small, lightweight, efficient, and economical without increasing the cross-sectional area of the iron core more than necessary. The company aims to provide welding machines.

(Structure of the Invention) A first aspect of the present invention is that on the primary side of an insulating transformer for welding,
It has a frequency conversion circuit, and the commercial frequency f.

(5) In an arc welding machine configured to supply a power source with a frequency higher than (Hz) to the welding insulating transformer, an amorphous metal magnetic material is provided in the iron core of the welding insulating transformer. The frequency f when the magnetic flux density of the amorphous metal magnetic material is constant.

The value of f is determined, and the relationship between the weight A (kg) of the iron core of the welding insulating transformer and the rated input capacity B (KVA) is such that A≦1. .

The present invention is characterized in that the iron core weight A (kg) and rated input capacity B of the welding insulating transformer are set so as to be 2.

(6) (Description of Examples) As a magnetic material with low core loss even in a high frequency range, a magnetic material made of amorphous metal can be mentioned. A comparison of the core loss characteristics of a conventional silicon steel plate and an amorphous metal magnetic material is shown in FIGS. 3 and 4. As can be seen from FIGS. 3 and 4, the core loss of the amorphous metal magnetic material is smaller than that of the silicon steel plate. Therefore, if the magnetic material is an amorphous metal, the iron loss will be small even if the frequency is increased, so there is no need to increase the cross-sectional area of the iron core more than necessary, and the insulating transformer for welding can be made smaller and lighter. As a result, an arc welding machine having a frequency conversion circuit having the configuration shown in FIG. 2 can be provided in a smaller size and lighter weight. That is, from FIG. 3 and FIG. 4, the iron loss of amorphous metal magnetic material is about 1/4 or less of silicon steel plate, and if other conditions are the same, the iron core weight is also about 1/4 It is possible to do the following.

8 FIG. 5 is an example showing the relationship between the input KVA and the iron core weight of a conventional welding insulation transformer using a silicon steel plate as the magnetic material. As shown in Figure 5, if the 1g value of the weight of the iron core made of silicon steel plate is A1 manual KKVA value B, then A
is approximately twice as large as B (A≧2B). Therefore, from FIGS. 3 and 4, if the weight of the iron core made of amorphous metal magnetic material is A', Δ'uni 10091111. (5) 4 Therefore, by substituting A≧2B into equation (5), we get A', that is, A'≧tan... (6) 2B-42, and the iron core weight A' is the input KVA value B. It will be about 1/2.

By the way, the weight of the iron core can be reduced by increasing the frequency according to equation (1), but as shown in Figure 6,
As the frequency increases, the iron loss also increases, so (1
) It is not possible to reduce the cross-sectional area of the iron core in martial arts.

Therefore, it becomes necessary to set the frequency within a range in which the rate at which the iron loss increases is small relative to the rate at which the frequency is increased.

In other words, the iron loss of the iron core at commercial frequency fo (CWA9)
If the value is Plo, and Pi is the iron loss (w/k17) value of the iron core when the frequency of the power supply supplied by the frequency conversion circuit 6 in Fig. 2 is 1, then when the magnetic flux density of the iron core is constant, It is possible to reduce the cross-sectional area of the iron core only when the formula holds true. Furthermore, the frequency f can be increased to the point where the equation holds if the cross-sectional areas of the iron cores are the same.

be. From FIG. 7, it can be seen that the equation holds true when the frequency f is 15 kHz or less.

(9) Therefore, from equation (7), if the magnetic flux density of the iron core is constant, the frequency f is 15 kHz'! If it is within the range of
As shown in FIGS. 3 and 4, by using an amorphous metal magnetic material, it is possible to secure the weight of the iron core to be approximately 174 mm or less compared to when a silicon steel plate is used. In other words, from equation (6), it is possible to manufacture an insulating transformer for welding where A'≦tan holds, and 1/2 of the input KVA value.
It is possible to reduce the size and weight with the following iron core weight (kl?) value.

Furthermore, when the frequency f is set to 15 kHz or higher, within the range where the equation holds true, the iron core type -X 2.74=
0.68, and it is possible to manufacture the iron core with a weight of 68 mm compared to silicon steel plate. Therefore, here, in equation (7), (6
) If the formula holds true, it is possible to make the core smaller and lighter than the core weight of a conventional welding insulating transformer that uses a silicon steel plate for the core, and therefore arc welding This allows the machine to be made smaller and lighter.

(Effects of the Invention) As detailed above, the present invention determines the value of the frequency f so that the welding insulation quality≦1, and the weight A of the iron core and the rated human power B so that A≦− is satisfied. By determining this, the weight of the iron core can be significantly reduced, especially when the frequency
The effect is particularly remarkable in a region where the frequency is relatively low, for example, below 15 kHz.

By setting the iron core weight A and the rated manpower B, the iron core weight can be reduced, especially in a relatively high frequency range, e.g.
It is more effective at frequencies above kHz.

In addition, as described above, if the welding insulation transformer becomes smaller and lighter, the amount of winding wire used will be reduced, which will reduce the winding cost and reduce loss, resulting in power savings and economical. It is possible to provide an arc welding machine with rich characteristics.

[Brief explanation of the drawing]

FIG. 1 shows an example of the configuration of a conventional arc welding machine. FIG. 2 shows an example of the configuration of an arc welding machine having a frequency conversion circuit. FIGS. 3 and 4 show comparative examples of iron loss between silicon steel and amorphous metal magnetic material. Figure 5 shows the iron core weight and rated input capacity (KVA) of a welding insulation transformer for a conventional arc welding machine that uses silicon steel for the iron core.
) is shown below. FIG. 6 shows an example of the relationship between core loss and frequency of an amorphous metallic magnetic material. FIG. 7 shows a schematic diagram of the amorphous metal magnetic material shown in FIG. 6. (13) Figure 1 Figure 2 Figure 5 Input VAB (to VA) - Figure 6 Magnetic tree density (Tesla) - (-Weber/m2)

Claims (2)

[Claims] (1) The primary side of the welding isolation transformer has a frequency conversion circuit, which converts the frequency f (Hz) higher than the commercial frequency f (H2).
) in an arc welding machine configured to supply a power source to the welding insulating transformer, an amorphous metal magnetic material is used for the iron core of the welding insulating transformer, and the amorphous metal magnetic material is The value of f is determined so that the magnetic flux density is constant,
and the weight A (ky) of the iron core of the welding insulation transformer.
and rated input capacity B (KVA) such that A≦7. (2) A frequency conversion circuit is provided on the primary side of the welding isolation transformer, and a frequency f (Hz) higher than the commercial frequency f (Hz) is provided.
) is supplied to the welding insulating transformer (1), in which an amorphous metal magnetic material is used for the iron core of the welding insulating transformer, An arc welding machine characterized in that the value of f is determined so that the magnetic flux density of the magnetic material is constant, and the arc welding machine is configured to be used for welding.