JPS6410845B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention is an arc generation power supply device that generates an arc in a load consisting of a xenon lamp or a non-consumable electrode of a TIG arc welding machine. The present invention relates to a power supply device for arc generation.

Conventionally, a power supply device that generates an arc in a xenon lamp or a non-consumable electrode of a TIG arc welding machine, which is a light source load of a projection power supply device, generally has a configuration as shown in FIG. That is, a main DC power supply circuit 2 for supplying arc voltage to a load (not shown) is connected to the AC power supply 1, and the DC output of the main DC power supply circuit 2 is connected to a smoothing reactor 3 and a smoothing capacitor 4. , is applied to the non-consumable electrode of the load from the output terminal 7 via the reverse current prevention diode 5 and the voltage superimposition capacitor 6, and the DC output is smoothed by the smoothing reactor 3 and the smoothing capacitor 4 to reduce ripple. , to prevent arc breakage in the load. Also,
In order to generate an arc in a load such as a non-consumable electrode, it is necessary to apply a high voltage to break the gap between the electrodes at startup. A superimposing DC power supply circuit 8 and a superimposition capacitor 6, which are connected in parallel to the power supply circuit 2 and have the characteristic of drooping with a small current, supply the output voltage of the main DC power supply circuit 2 to the load, thereby generating an arc. It's becoming like that. At this time, the backflow prevention diode 5 prevents a high no-load voltage from being applied to the smoothing capacitor 4, thereby preventing the withstand voltage of the smoothing capacitor 4 from becoming high.

However, the above-mentioned power supply device is provided with a superimposing DC power supply circuit 8 separately from the main DC power supply circuit 2, which is the main circuit, and in order to configure this superposition DC power supply circuit 8, a transformer, Impedance elements such as diodes and resistors for dropping the no-load voltage are essential components, which makes the configuration complicated and the device large, and requires a lot of man-hours and is expensive to manufacture. There are various drawbacks.

This invention takes into consideration the drawbacks of the conventional art and attempts to simplify the structure to reduce size and cost. Next, the present invention will be described with reference to FIGS. 2 and 3, which show embodiments thereof. This will be explained in detail.

First, the basic structure of the present invention will be explained with reference to FIG. 2 showing one embodiment. In the same figure, the same symbols as in FIG. In addition, both ends of the first winding of the transformer are connected to the DC power supply circuit 2' through a rectifying and smoothing circuit (not shown) configured in the DC power supply circuit 2'. This is because it is led out and connected to both ends of the backflow prevention diode 5.

Next, the operation of the embodiment will be explained.

When AC power supply 1 is applied to DC power supply circuit 2',
Due to the DC output of the DC power supply circuit 2, a voltage indicated by [V ₁ ] is generated across the smoothing capacitor 4, and a voltage of [V 1 ] is generated across the reverse current prevention diode 5 at both ends of the first winding of the transformer of the DC power supply circuit 2'. A rectified and smoothed voltage is applied, and these two voltages [V ₁ ], [V ₂ ]
is added by the superposition capacitor 6, and a high voltage shown as [V ₁ +V ₂ ] is generated across the superposition capacitor 6. This high voltage [V ₁ +V ₂ ] is applied to the load from the output terminal 7, and the load An arc occurs between the electrodes. And when an arc occurs in the load,
The impedance of the load decreases, a large current flows from the DC power supply circuit 2' to the load via the smoothing reactor 3 and the reverse current prevention diode 5, and the voltage [V ₂ ] applied to the aforementioned reverse current prevention diode 5 decreases. becomes only a forward voltage (approximately 1.5 V) and drops, and the voltage [V ₁ ] from the half-wave rectifier circuit of the DC power supply circuit 2' is supplied to the load.

Next, FIG. 3 shows another embodiment when applied to an arc welding machine having a non-consumable electrode, in which the same symbols as in FIGS. 1 and 2 indicate the same things, The primary winding Ta of the transformer T is triangularly connected and connected to the input terminal I of the three-phase AC power supply, and the secondary winding Tb is connected in a double star shape and one end of each of the six phases is connected. The point is connected to the positive side output terminal 7' via the backflow prevention diode 5, and further,
Each cathode of the first to sixth thyristors TH ₁ to _{TH 6} is connected to each other end of the six-phase secondary winding Tb, and the connection point of each anode of the first to third thyristors TH ₁ to _{TH 3} is connected to the other end of the 6-phase secondary winding Tb. 4th to 6th thyristor TH ₄ ~
Connect both ends of the interphase reactor L that protects each thyristor _{TH 1 to} TH ₆ by balancing the current between both secondary windings Tb of the 3-phase star-connected to the connection point of each anode of TH 6. to configure a double star-shaped six-phase half-wave rectifier circuit RC with an interphase reactor, and connect the intermediate tap of the interphase reactor L to the negative output terminal 7'' via the smoothing reactor 3.
In addition, a rectifying diode D, a drooping resistor R, and a no-load voltage smoothing capacitor C are connected in series between both ends of the first winding n of the secondary winding Tb of the transformer T. C is connected in parallel to the reverse current prevention diode 5, and a DC power supply circuit 2'' is constituted by the transformer T, half-wave rectifier circuit RC, rectifier diode D, drooping resistor R, and no-load voltage smoothing capacitor C. .

Next, the operation of the embodiment will be explained.

When 3-phase AC power is applied to input terminal I at startup, this 3-phase AC input is boosted or stepped down by transformer T, and then controlled by a double star-shaped 6-phase half-wave rectifier circuit RC with an interphase reactor. It is rectified and further smoothed by a smoothing reactor 3 and a smoothing capacitor 4. On the other hand, the first winding n of the secondary winding Tb of the transformer T
The voltage generated across the backflow prevention diode 5 is half-wave rectified by the rectifier diode D, smoothed by the no-load voltage smoothing capacitor C, and applied to both ends of the backflow prevention diode 5. Therefore, a large voltage, which is the sum of the voltage across the smoothing capacitor 4 and the voltage across the backflow prevention diode 5, is generated across the superimposing capacitor 6, and this large voltage is generated at both ends of the superimposing capacitor 6. An arc is generated by applying an electric current between the consumable electrode and the base metal. When an arc occurs in the load, the impedance of the load becomes low, and a large current flows from the transformer T to the load via the double star-shaped 6-phase half-wave rectifier circuit RC with an interphase reactor and the backflow prevention diode 5. Backflow prevention diode 5
The voltage becomes only the forward voltage (approximately 1.5V). Therefore, the voltage of the series circuit of the rectifier diode D, the drooping resistor R, and the no-load voltage smoothing capacitor C drops, and the load is supplied with the DC power supply circuit 2'' consisting of the transformer T and the half-wave rectifier circuit RC. Arc voltage is supplied only from the main circuit.

Note that if the voltage of the first winding n of the secondary winding Tb of the transformer T is insufficient for the superimposed voltage generated across the backflow prevention diode 5 to generate an arc, the voltage of the first winding n An additional winding tap may be provided to boost the voltage for superimposition. Also,
In the embodiment shown in FIG. 3, the DC power supply circuit 2'' is configured with a double star-shaped six-phase half-wave rectifier circuit RC with an interphase reactor, but it may also be configured with a three-phase half-wave rectifier circuit, a six-phase half-wave rectifier circuit, or a two-phase half-wave rectifier circuit. The DC power supply circuit may be configured by a half-wave rectifier circuit such as a wave rectifier circuit.

Furthermore, the transformer T may be provided with a tertiary winding, and the voltage of the tertiary winding may be rectified and smoothed to be applied to the backflow prevention diode 5. In that case, the DC power supply circuit may be connected to all three phases. It can also be configured by a wave rectifier circuit.

As described above, the arc generating power supply device of the present invention includes a DC power supply circuit constituted by a transformer connected to an AC power supply and a half-wave rectifier circuit connected to the secondary side of the transformer, and A backflow prevention diode connected between the DC output end of the power supply circuit and a load that generates an arc consisting of a xenon lamp or a non-consumable electrode of a TIG arc welding machine; A rectifying and smoothing circuit is provided between both ends of the backflow prevention diode, and rectifies and smoothes the voltage generated in one winding of the transformer, and applies the rectified and smoothed voltage to the backflow prevention diode.

Therefore, according to the present invention, the superimposing DC power supply circuit provided in the conventional power supply device is not required, the configuration can be greatly simplified, the device can be made smaller, and the manufacturing process can be reduced. Man-hours can be reduced and the cost is low.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a conventional arc generating power supply device, Fig. 2 is a block diagram of one embodiment of the arc generating power supply device of the present invention, and Fig. 3 is a wiring diagram of another embodiment of the present invention. be. 1...AC power supply, 2', 2''...DC power supply circuit,
5...Reverse current prevention diode, T...Transformer,
RC...half-wave rectifier circuit, D...rectifier diode,
C...Smoothing capacitor.

Claims (1)

[Claims] 1. A DC power supply circuit consisting of a transformer connected to an AC power supply and a half-wave rectifier circuit connected to the secondary side of the transformer, and a DC output end of the DC power supply circuit and a xenon lamp or TIG arc welding machine. a backflow prevention diode comprising a non-consumable electrode connected between the load that generates an arc; and a backflow prevention diode connected between both ends of the first winding of the transformer and both ends of the backflow prevention diode, the transformer 1. A power supply device for arc generation, comprising a rectification and smoothing circuit that rectifies and smoothes the voltage generated in one winding of the arc generator and applies the rectified and smoothed voltage to the backflow prevention diode.