JPS5820376A - High frequency pulse arc welding machine - Google Patents

Abstract

PURPOSE:To provide a titled welding machine which is decreased of the losses generated by wiring inductance and uses a low voltage circuit for a DC power source part by creating high frequency pulses with an LC resonance circuit consisting of a resonance capacitor and a resonance coil and switching means. CONSTITUTION:In a circuit for a high frequency pulse arc welding machine, 3-phase AC voltage of about 50V is applied to input terminals U, V, W, and a DC power source part 60 is constituted of a 3-phase bridge rectifier circuit 27, a smoothing capacitor 28, a chopper transistor 29 and a control circuit 30 thereof, a diode 31, a chock coil 32, etc. One terminal of a capacitor 33 for resonance connects to the work 36a of arc load 36 via a shunt 35, and the other terminal connects in series to a thyristor 34 for switching means, a saturable reactor 37 for resonance coil, and an electrode 36b. A DC power source 39 of small capacity and an arc starter 40 are connected to the work 36a and the electrode 36b.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-frequency pulsed arc lIMIkK that performs arc melting using a high-frequency pulsed current.

In a DC arc S textile machine, when a high frequency pulse current component with a frequency of 10KIlz-100m is applied to the s1 electrical current flL, regardless of whether it is a non-consumable electrode type or a consumable electrode type,
Excellent straightness and stability of the arc, allowing high-speed melting
D. It is well known that the bead will become jealous and the 1111 characteristics will change with modification from a metallurgical point of view.

FIGS. 1(A) to 1(C) are a circuit diagram and an arc current waveform diagram, respectively, showing an outline of the configuration of a conventional Ill printing machine of this type. In FIG. 1(A), when the switch 1 is turned on, the positive voltage of the DC power source 2 is supplied to the Sm object 3 through the wiring inductance L.

The negative voltage of the DC power source 2 is supplied to the electric current 3b via the switch 1, and the Puke electric current tILx, which gradually rises between the proboscis 3a and the electrode 3b, flows between the fins and the proboscis 3a (period ' in the waveform diagram). l't). Hereinafter, the S contact object 3m and the electrode 3b will be referred to as an arc load 3.

Next, when the switch l is turned off when the arc current I reaches a certain value, the energy stored in the wiring inductance L creates a path of wiring inductance L → arc load 3 → diode 4 → wiring inductance L → Then, when the arc current I decreases to a certain value and is good, the switch I is turned on again, and the above operation is repeated to generate a pulse. An arc current I of tIl is applied to the arc load 3.

In addition, when switches 5 and 6 are both turned on in FIG. 2 (b), arc current X flows to arc load 3 through switches 5 and 6 (period Zs in the waveform diagram).
. When this arc electric RI reaches a certain value, the switch 5
．． 6 are both off.

, due to the energy stored in the wiring inductance L, an arc current rlLx flows through the path of wiring inductance L → diode 7 → DC power supply 2 → diode 8 → arc load 3 → wiring inductance L T4), the above operation is repeated thereafter.

When the first Eri scent switch 11 is turned on, arc electricity ILx flows to the arc load 3 through this switch 111 (period 114TI in the waveform diagram).

When the switch 11 is turned off next time, the energy stored in the wiring inductance L causes the wiring inductance L. → arc load 3 → diode 12 → gongden t.
13→DC power supply 2→Wiring inductance L
), and at this time, the energy stored in the wiring inductance is transferred to the capacitor 13. Condan? 1
The energy stored in switch 14j?3 is turned on and off at a longer cycle than switch 11. and coil 1B
is regenerated to the DC power supply 2 through the

The above is an example of the configuration of a conventional high-frequency pulse arc machine.
As mentioned above, these complimentary rice products have the following drawbacks:
Wow.

■ A circuit that absorbs energy stored in the wiring inductance L (diode 4 in Figure 1,
7, 8, 12all) are required.

■ At the peak point of arc current, switch 1, 5, 6°11
Rounding off, these switches 1,5 need to be turned off.
, 6.11, it is not possible to use Irista,
A transistor must be used. As is well known,
A thyristor has an overcurrent withstand capacity 20 times greater than a transistor with the same rating, and therefore, a thyristor is much more advantageous as a switching element.

This invention has been made in view of the above-mentioned nine circumstances, and the wiring inductance L
・Provides a high-frequency pulse arc welding machine that does not require an absorption circuit for the energy stored in the LO and uses a thyristor as a switching element. It is a feature.

An embodiment of the present invention will be explained below with reference to one drawing.

FIG. 112 is a circuit diagram showing the configuration of a high frequency pulse arc welding machine manufactured by Jin's vAIlc. In this figure.

The input terminals u, v, and w are terminals to which a three-phase AC voltage of about 50V is applied, and the three-phase AC voltage applied to the input terminals υ, V, and W is connected to three terminals consisting of diodes 21 to 26.
It is rectified by the phase bridge rectifier circuit 27 and supplied to the smoothing filter t2s.

Then, the voltage obtained at the e terminal of the smoothing capacitor 28 is supplied to the two transistors. The transistor 29 is a wire transistor that is turned on/or by the output of the control circuit 30 supplied to its base, and its emitter is connected to the cathode IIcjI! of the flywheel diode 31. At the same time as being tied up,
It is connected to one terminal of a resonance conductor 933 via a coil 32. e of the smoothing capacitor 28
The terminals are closely connected to the anode of the flywheel diode 30 and the other terminal of the resonant capacitor 33. Each of the above-mentioned @Z'l~32 is the DC power supply section 6.
It constitutes 0. One terminal of the resonant capacitor 33 is connected to the S* object 36avcii of the arc load 36 via a shunt 35 for current detection, and the other terminal of the resonant capacitor 33 is connected to the cathode of the thyristor 34 (#lI closed hand a). In addition, the anode of the thyristor 34 is connected to the arc load ≦6 through the saturable reactor 37 (resonant coil #).
The electrodes of s s b vctams are &, -tL”
c, Q/'(n) 3 The voltage across B is 1llll#lI
, and is supplied to route 30. A DC power supply 39 and an arc starter 40 are connected between both ends of the series circuit of the first shunt 3B and the arc load 36, respectively. The DC power supply 39 always supplies a small current in to the arc load 36 (for example,
A power source with relatively little ripple is used, with a round power source that flows through the power source (S person). The reason why this small current in is constantly passed through the arc load 36 is to prevent the arc from breaking even during a period when no pulse current is applied to the arc load 36F. Before starting, the arc starter 40 is exposed to S at the time of startup.
*It is a rounded thing that destroys the insulation of the air gap between the thing 36 and the electrode 86b, and it is about IM 30 at the time of startup.
A picture frequency AC voltage of 0.00 V is applied to the arc load 36 for a short time. Note that the gate of the thyristor 34 is triggered by a pulse signal GP of a constant period (this period can be changed) output from a pulse generation circuit (not shown).

Next, the operation of the enclosure having the above configuration will be explained with reference to the waveform diagram shown in FIG. I will clarify.

In this embodiment, in the DC power supply section 5o6c, the w*m path 30 controls the on/off of the transistor 29 so that the average value of the current flowing through the circuit 33 is kept constant. As a result, the voltage across the smoothing capacitor 928 is turned ON/OR 111 by the transistor 29, and is applied to both ends of the resonance capacitor f'4B via the chiroke coil 32, thereby charging the resonance capacitor 33. It will be done.

Next, at 1, for example, the time "tel" shown in FIG.
tWhen the iris tacho 4 is turned on, the resonance conductor 9
4B, the shunt 35, the arc load 36°, and the saturable reactor 37 form a series resonant circuit, and a resonant current [it] flows due to the charged charge of the resonant capacitor 33. By the way, the saturable reactor 37 is in an unsaturated state when the current is small.

It has a large inductance. Shut up.

The amount of resonant current gradually increases as shown in FIG. ~is).

And the amount of current! When reaches a certain value i@(time t
s), the saturable reactor 37 is saturated.

The electric current Kit rapidly increases according to the resonance characteristics determined by the saturation inductance of the saturable reactor 37 and the capacitance of the resonance capacitor 330.

Further, along with this, the charges in the resonance conductor 33 are discharged, and the voltage Pc across it rapidly decreases as shown in FIG. 3, 11.

Due to the nature of the I1wA path, the electric current Rit rises at the point where the electric voltage Ec becomes zero. Then, after time t3 when it becomes zero, it rapidly decreases, and at this time, the resonance capacitor 33 is charged to a negative voltage. Current l! falls and reaches ill@ (time t4), the saturable reactor 37 becomes unsaturated again and the amount of current is %! will gradually decrease thereafter. After time t4, the resonance capacitor 33 continues to be charged by the current it, but this charging current is small, and the direct output coil 32 is unaffected by the voltage change of the power supply 133. A certain ninth time t4
Thereafter, the electric current ale across the resonance capacitor 33 gradually rises due to the charging current imK from the DC power source gso.

Current i! decreases and becomes zero at time is, and at this point, the inverse z(ias) is applied between the anode and cathode of the SIRIS/34 by the resonant condenser 93B&IC, so the iriscopter 4 enters the cut-off state. , l!The shaded area shown in Figure 3 h iVc is thyristor 3.
This corresponds to the inverse p<Ias time of 4. Thereafter, the resonance conductor 933 is self-charged by the electric fiim,
Voltage Bc increases successively. Then, at time t4, I
(When the pulse signal GP is applied to the gate of the iris taco 4 again.

The thyristor 34 is turned on, and the nine operations described above are repeated again.

Therefore, the above-mentioned current 11 and electric current t are applied to the arc load 36.
(See Figure 3)
This current causes a pulse arc 11! Ika row
t be beaten.

In the above-described embodiment, the saturable reactor 37 is used as the resonant coil, but the pulse arc welding machine using the oscillating INK can also use an ordinary coil as the resonant coil. However, if a normal coil is used, the disadvantages described below occur, and therefore it is desirable to use a saturable reactor.

In other words, when a coil with a convoluted structure is used, a smooth fall between time 14 and i1 in Fig. 3 (-) cannot be obtained;
The current 1t rapidly drops to zero. As a result, a negative recovery current indicated by the symbol M flows through the thyristor 34 at the fourth wA, and this current causes the electrical arc to break or become unstable. This recovery current is determined by the current decreasing slope −d i
t / d In proportion to t
At a current decreasing slope of pm/pm, a recovery current of @l0AQ is generated.

(In addition, in the case of a high-frequency pulse arc** machine, if a saturable reactor is not used, the current decrease slope after 30 μm/μsg described above will occur.) This recovery electric current 11. In order to maintain the arc current normally in response to the ii* due to current becomes impossible, which is extremely undesirable.

However, in the embodiment described above, only the saturable reactor 37 is used as the resonant filter.

Since the impedance of the saturable reactor 37 at saturation is usually very small, another resonant filter (common rt coil with relatively small inductance) may be inserted in series with the saturable reactor 37.

Further, the rectifier circuit 27 in the above-described embodiment may be formed of a thyristor and the eye-flange transistor 29 may be removed, but the circuit shown in the embodiment is more advantageous in terms of ripple.

As explained above, according to the present invention, a high frequency pulse is generated by the LO resonance circuit and the switching means.
The following advantages are obtained:

■ Because the switching means turns off when the current is zero.

The loss caused by the energy absorbing circuit with wiring inductance (10mHQ degree) can be made extremely small (compared to the conventional 1750 to 100m).

■ Cyrisk can be used as the opening/closing means.

■ The DC power supply section can be a low voltage circuit, which is advantageous in terms of parts, etc.

(2) The control of the DC power supply section (in the second E embodiment, the front control) can be controlled at a low frequency, and the configuration of the control circuit of the DC power supply section can be simplified.

In addition, when a saturable reactor is used as a resonant coil, the negative influence of arc current -1 can be removed, and the i4
An advantage is obtained that the switching loss of the M means can be made extremely small.

[Brief explanation of drawings]

ts1 diagram) - el are a circuit diagram and an arc current waveform diagram showing the configuration of a conventional high frequency/(Russ arc welding machine), respectively;
FIG. 2 is a circuit diagram showing the configuration of an embodiment of the present invention, and FIG.
(Figures) are aE for explaining the operation of the same embodiment.
llIrjA, Figure 4 shows the sirisk glue coverage current i
1! FIG. 33... Pundenna for resonance, 34... Thyristor (
opening/closing means), 36... arc load, 37... saturable reactor (resonant filter), 60... tim power supply section. Origin: Shinko Electric Co., Ltd. 1st L. figure

Claims (2)

[Claims] (1) A DC power source, a resonant conditioner to which the DC current output from the DC power source is applied, and a switching means;
A high-frequency pulse ater S* machine comprising a resonant quill, and the opening/closing means, common @* quill, and arc load are inserted in series at both ends of the resonant quill. (2) The high-frequency pulsed arc S fiber machine according to claim 1g4, wherein the resonant coil is a saturable reactor or a series circuit of a saturable reactor and a filter.