JPS5997781A - Power source device for welding - Google Patents

Abstract

PURPOSE:To make a welding interval suitable for a high speed welding line by installing the 1st and 2nd capacitors, and using the electric charge in the 1st capacitor for charging the 2nd capacitor when the 2nd capacitor is put in the discharging state. CONSTITUTION:When the timing signal of a timing control circuit 38 shifts from a low to high level upon opening of a switch 42 by the rotation of a cam 44, a switching control circuit 32 generates a high level output and a switching transistor 6 shifts to a conducting state. As a result, the 1st capacitor 28 and the 2nd capacitor 30 are short circuited, then the charge charged in the capacitor 28 migrates to the 2nd capacitor 30, and the capacitor 30 is charged. The charging in the 1st capacitor 28, and the discharging and charging of the 2nd capacitor 30 accompanied with welding are thus completed in response with the rotation of the cam 44 in one round period and since the charging in the capacitor 30 is instantaneously completed, the time from the welding to the succeeding welding is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a welding power source, and particularly to one suitable for a welding power source in a high-speed welding line.

FIG. 1 shows a welding power supply device installed in a welding device of a high-speed welding line. A rectifier circuit 4 is connected to the AC power supply 2, and a capacitor 8 is connected to the output side of the rectifier circuit 4 via a switching transistor 6. At the base and emitter of the switching transistor 6,
A welding control circuit 10 is installed to control the welding timing and the charging timing of the capacitor 8, and a welding command pulse is applied to a command input terminal 12 of the welding control circuit 10 from a switch or the like. That is, when charging the capacitor 8, the switching transistor 6 is controlled to be in a conductive state, and during welding, that is, when the capacitor +8 is being made to be in a discharging state, the switching transistor 6 is controlled to be in a non-conductive state.

A welding transformer 16 is connected between the terminals of this capacitor 8 via a SIRISK (SCR) 14 which is a switching element.
The 11th coil 18P is connected. A welding electrode is connected between terminals 20 and 22 of the secondary coil 18S of the welding transformer 16.

Pulse transformer 2 is installed between the gate and cathode of 5CR14.
A trigger circuit 26 is connected to the welding control circuit 26 through the welding control circuit 10, and a trigger pulse for controlling the 5CR 14 to be conductive during welding is applied to the trigger circuit 26 from the welding control circuit 10.

In such a welding power supply device, welding is performed with the capacitor 8 in a discharged state, and the next welding is performed after waiting for the capacitor 8 to rise to a predetermined charging voltage. Therefore, the charging speed of the capacitor 8 affects the welding speed.
Such a welding power supply device cannot be used in a high-speed welding line because the charging speed of the capacitor 8 is slow.

In the present invention, first and second capacitors are installed, and when the second capacitor is placed in a discharge state during welding, the first capacitor is charged and the charged charge is used to charge the second capacitor. The purpose of the present invention is to provide a welding power supply device which uses a welding device to shorten charging time and has a welding interval suitable for a high-speed welding line.

Embodiments of the invention will be described in detail with reference to the drawings. FIG. 2 shows an embodiment of the welding power supply device of the present invention.
The same parts as those in the figure are given the same reference numerals. In the figure,
A first capacitor 28 is connected to the output side of the rectifier circuit 4, and a second capacitor 30 is connected to the first capacitor 28 via a switching transistor 6. The function of the second capacitor 30 corresponds to the capacitor 8 in FIG. 1, and the first capacitor 28 is installed to charge the second capacitor 30. The first capacitor 28 has a larger capacity than the second capacitor 30.

A switching control circuit 32 for controlling switching is connected to the base and emitter of the switching transistor 6, and a power supply 36 is connected to a voltage setting terminal 34 of the switching control circuit 32 to set a reference voltage. That is, this switching control circuit 32 is configured to control the switching transistor 6 to be non-conductive when the charging voltage of the second capacitor 30 reaches this reference voltage.

Then, the switching control circuit 32 and the trigger circuit 26
A timing control circuit 38 is connected to the capacitor 30, and the timing control circuit 38 generates a charging timing for placing the switching transistor 6 in a conductive state and a discharging timing for controlling the capacitor 30 in a discharging state. A switch 42 that generates a command signal is connected to the command input terminal 40 of this timing control circuit 3rd.
The notch 42 is a cam 44 that is linked to the drive system of the welding line.
It is designed to open and close with.

The operation of the above configuration will be explained with reference to the operation timing shown in FIG. It is now assumed that the first and second capacitors 28 and 30 are both charged and held at a predetermined voltage. In this state, when the switch 42 is closed by the rotation of the cam 44 as shown in FIG. Shifts the base current to a lower level. As a result, the switching transistor 6 becomes non-conductive as shown in FIG. 3B.

Further, when the timing control circuit 38 generates a timing signal that changes from a high level to a low level to the trigger circuit 26 as shown in FIG. A trigger pulse shown in Figure 3 is generated. This trigger pulse is applied to the gate of 5CRI4 via the pulse transformer 24, and at this time, 5C
R14 becomes conductive. As a result, the second capacitor 30 is short-circuited via the primary coil 18P of the welding transformer 16, and due to the discharge of the second capacitor 30, a high voltage AC waveform shown in FIG. 3E is generated in the welding transformer 16. . This AC voltage is applied to the primary coil 18P, secondary coil 1
83, a large current is generated at a low voltage in the secondary coil 183, and this generated current is transferred to the terminal 20.2.
It flows to the electrode between the two, and welding occurs instantly. At this time,
When the discharge waveform ends, the 5CR14 becomes non-conductive and waits until the arrival of the next trigger pulse.

FIG. 3F shows the transition of the terminal voltage of the second capacitor 30, and the charging voltage of the second capacitor 30 becomes a low voltage due to conduction of 5CR14.

Further, when the switch 42 is opened by the rotation of the cam 44 and the timing signal of the timing control circuit 38 changes from a low level to a high level as shown in FIG. 3A, the switching control circuit 32 generates a high level output. Sui 7
The switching transistor 6 becomes conductive as shown in FIG. 3C.

As a result, the first capacitor 28 and the second capacitor 30 are short-circuited due to conduction of the switching transistor 6, and the charge in the first capacitor 28 is transferred to the second capacitor 30. is charged as shown in FIG. 3F.

The charging voltage Vc2 of the second capacitor 30 is Sui.

When the reference voltage Vref (=Vc2) detected by the switching control circuit 32 and set by the power supply 36 is reached, the switching transistor 6 is controlled to be non-conductive.

FIG. 3G shows the discharge waveform of the first capacitor 28 that occurs when the second capacitor 3° charges, and Vcl is its terminal voltage.

In this way, in response to the rotation of the cam 44, the first
Since the charging of the capacitor 28 and the discharging and charging of the second capacitor 30 accompanying welding are completed, and the charging of the second capacitor 30 is completed instantly, the time from one welding to the next welding can be shortened. Therefore, welding work can be performed efficiently on a high-speed welding line.

In addition, in the example, the case where the switch inserted between the first and second capacitors is configured with a switching transistor has been explained, but similar results can be expected even if a mechanical switch other than an electronic device is used. . Further, although the case where an SCR is used as the switching element has been described, the same effect can be expected even if a switching transistor or a mechanical switch is used as the switching element.

As explained above, according to the present invention, the first and second capacitors are installed, and when the second capacitor is placed in a discharged state during welding, the first capacitor is charged and placed, and the charged charge is Since the charging time can be shortened by using the second capacitor to charge the second capacitor, the welding interval can be shortened, and efficient welding work can be performed on a high-speed welding line.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a conventional welding power supply device, FIG. 2 is a circuit diagram showing an embodiment of the welding power supply device of the present invention, and FIG.
The figure is an explanatory diagram showing the operation timing. 6... Switch-notching transistor as a switching element, 14... Sairisk as a switching element, 28... First capacitor, 30... Second
capacitor. Figure 2 Figure 3

Claims (1)

[Claims] a first capacitor that is charged by applying a DC voltage;
a second capacitor installed on the primary side of the welding transformer via a switching element that controls conduction during welding;
The first capacitor is inserted between the first capacitor and the second capacitor, and is controlled to be in a non-conducting state when the second capacitor is placed in a discharging state, and is controlled to be in a conducting state when charging the second capacitor. The second charge of the capacitor is
A power supply device for welding, comprising a switch for charging a capacitor.