JPH0519178Y2 - - Google Patents

Description

[Detailed description of the invention] "Industrial application field" This invention controls the output current by switching the output winding when welding in the weak current region and welding in the strong current region, and thereby controls the output current under various welding conditions. The present invention relates to an output control device for a welding generator that can adjust the output current over a wide range to suit various purposes and can be used for a variety of purposes.

``Problems to be solved by conventional techniques and inventions'' Traditionally, welding generators maintain the current supplied to the field winding constant, and use a saturable reactor or thyristor on the output side to generate one output winding. There is one that adjusts the output current output from the line.

However, in this type of output current control method, the entire range from the weak current region to the strong current region is adjusted using the saturable reactor or thyristor. If the output current is adjusted using a thyristor, a large one corresponding to the maximum adjustable output current value must be used. When used as a welding machine, the value of the welding current, which is a short circuit current, is extremely large, so a thyristor with a capacity that can withstand the large current must be used, making it extremely expensive. Moreover, when the output current output from one output winding is adjusted over the entire range from the weak current region to the strong current region using the saturable reactor or thyristor, the output characteristic curve becomes particularly strong in the weak current region. Since the current is moved in parallel from the current region to the direction of small current and small voltage, the no-load voltage is also extremely reduced, and as a result, the recovery voltage during welding drops and arc breakage is likely to occur, making it impossible to expect good welding. Ta.

On the other hand, in recent years, there has been a demand for a single welding generator with multiple functions. For example, it is possible to perform not only gouging work that requires large currents, but also cutting, and when performing other work outdoors at night, the number of working machines used is minimized to reduce noise generation. Therefore, in addition to the above-mentioned functions such as welding, there is a need for a built-in AC auxiliary power source that exhibits constant voltage characteristics and can be used as a power source for lighting and grinders. However, the above-mentioned conventional welding generators have not been able to fully satisfy such demands.

Therefore, the present invention uses two types of output windings, one for weak current and one for strong current, and when performing work such as welding in the weak current region, only one output winding, that is, the first welding winding, is used. The output current of the first welding winding is adjusted and used, and when working in a strong current region, the output of the first welding winding is superimposed on the output of the second welding winding, and the output of the first welding winding is By adjusting the output current, not only can a small-capacity, compact, and inexpensive device be used as a device for adjusting the output current of thyristors, etc., but also there is a difference between welding in the weak current region and welding in the strong current region. As a result of switching and selectively using the respective outputs of the first welding winding and the second welding winding, it is possible to eliminate the drop in no-load voltage that can cause arc breakage when welding in the weak current range, and moreover, it is possible to eliminate the drop in no-load voltage that can cause arc breakage. It is an object of the present invention to provide an output control device for a welding generator that has convenient characteristics and gouging characteristics for use in various power sources such as tools, and is useful for use.

"Means to be Solved by the Invention" In order to achieve the above object, the present invention provides that the output windings of a welding generator are first welding windings for a weak current region that are electrically independent from each other. and a second welding winding for use in a strong current region with a small number of turns in order to set the maximum output lower than the first welding winding, and the first welding winding is full-wave rectified and welded. An output current adjustment device consisting of a thyristor and a diode for adjusting the current is connected, and the output current adjustment device is connected to the second welding winding via a rectifier for full-wave rectification and an open/close type strength changeover switch. The present invention is characterized by an output control device for a welding generator, which is connected to the output end and has an outlet for an AC auxiliary power source connected to the second welding winding.

Embodiment An embodiment of the output control device for a welding generator according to the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a first welded winding, and 2 is a second welded winding. The first welded winding 1 has a larger number of turns than the second welded winding 2, which results in an output characteristic curve 1 of the second welded winding 2 as shown in FIG.
The output characteristic curve 10 of the first welded winding 1 is set to be higher than that of the first welded winding 1 by a predetermined value. The first welded winding 1 and the second welded winding 2 each have a three-phase star connection. First welding winding 1
is connected to the output terminals 4 and 5 via the output current adjustment device 3. The output current adjustment device 3 is composed of a rectifier using a normal silicon diode and a thyristor whose firing angle is controlled by a phase control device 6. Therefore, the output current adjusting device 3 is capable of performing full-wave rectification of the output of the first welding winding 1 using the rectifier and the thyristor, and also adjusting the output value using the thyristor. On the other hand, the second welded winding 2 is
It is connected to the output terminals 4 and 5 through a rectifier 7 made of a normal silicon diode or the like and a low current changeover switch 8. The rectifier 7 performs full-wave rectification of the output of the second welding winding 2. Furthermore, an outlet 9 for taking out an AC auxiliary power source is connected to one phase winding 2a of the three phases of the second welding winding 2.

Incidentally, the output characteristics of the first welded winding 1 and the second welded winding 2 are as shown in FIG. 2. That is, the output characteristic of the first welding winding 1 exhibits a substantially constant voltage characteristic within a certain range A, as is clear from the maximum adjustable characteristic curve 10 in particular. Also in the output characteristics of the second welded winding 2, the characteristic curve 11 shown in FIG.
As shown, within the above range A, substantially constant voltage characteristics are exhibited.

Next, the operation of the output control device for the welding generator will be explained.

First, when welding in a weak current region, the strength changeover switch 8 is opened, and the firing angle of the thyristor of the output current adjustment device 3 is controlled by the phase control device 6, as shown in FIGS. 2 and 3. The output current can be freely adjusted to obtain a desired output current within the range up to the minimum characteristic curve 10 in the weak current region. At this time, the AC auxiliary power source can be used from the outlet 9 regardless of whether the welding current is taken out. This AC auxiliary power source is not affected by armature reaction so much as long as the current supplied to the field winding of the welding generator is constant and within a certain range of weak current. As shown in Figure 4, the output characteristic curve 13
It exhibits approximately constant voltage characteristics without drooping, and exhibits optimal characteristics as an AC auxiliary power source.

When welding in a strong current region, the strength changeover switch 8 is turned on. As a result, the output of the first welding winding 1 and the output of the second welding winding 2 are superimposed,
It is supplied to the outside from output terminals 4 and 5 as DC welding output. As mentioned above, the output of the first welding winding 1 is made to be higher overall due to the output of the second welding winding 2, and when switched to the strong current region by the strength changeover switch 8, Curve 15 in figure 3
As shown, the minimum value that can be adjusted by the thyristor of the output current adjustment device 3 is set to be slightly lower than the maximum value that can be adjusted in the weak current region (maximum characteristic curve 10). As a result, an overlapping region 14 is created between the maximum value of the weak current region and the minimum value of the strong current region, so that when switching from the weak current region to the strong current region, an unadjustable air space does not occur and it continues without interruption. You can adjust it by In this strong current region, it goes without saying that the thyristor of the output current adjustment device 3 can freely adjust between the minimum characteristic curve 15 and the maximum characteristic curve 16. In addition, in the strong current region, the output of the first welding winding 1 and the output of the second welding winding 2 are combined, so that a range exhibiting approximately constant voltage characteristics is created in a range where the current value is small; In addition to welding, it can be used as a power source for things that require DC constant voltage characteristics. Furthermore, in the strong current region, it exhibits characteristics suitable for performing gouging work that requires a large current, and is extremely convenient. Furthermore, when used in a strong current region, when the capacity taken out from the output terminals 4 and 5 is small, a small capacity AC auxiliary power output can also be taken out from the outlet 9 at the same time.

"Effects of the Invention" As described above, according to the output control device for a welding generator according to the present invention, the output winding of the welding generator has a first welding winding for weak current and a first welding winding for strong current. an output current adjusting device is connected to the first welding winding, and a second welding winding is connected to the output end of the output current adjusting device via a strength changeover switch, In addition, since the windings of the first welding winding and the second welding winding are different to provide a difference in the maximum output of each, the output from the first welding winding in the weak current region is When switching between welding and welding in a strong current region by the first welding winding and the second welding winding, a part of the weak current region and a part of the strong current region overlap, There is no gap where the output current cannot be adjusted by the output current adjustment device, and the output current can be adjusted continuously from the minimum value in the weak current region to the maximum value in the strong current region without interruption, which is convenient. Further, the output current can be adjusted in both the weak current region and the strong current region by connecting the output current adjusting device only to one side of the first welding winding. Not only the operation but also the configuration is simplified, and it is also convenient for promoting miniaturization. Furthermore, it is convenient because it can also be used as an AC power source for power tools and the like. Moreover, not only can a small-capacity, compact, and inexpensive device be used as a device for adjusting the output current of a thyristor, but also the first welding winding and the second As a result of switching and selectively using each output of the welding winding, when welding in a weak current region, the no-load voltage can be preset to a high value that does not drop much by the first welding winding,
It is advantageous in terms of use because it can eliminate the drop in no-load voltage, which is a cause of arc breakage as in the prior art, and has convenient characteristics for use in various power sources such as lighting tools.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the output control device for a welding generator according to the present invention, and FIG.
Figure 3 shows the external output characteristic curves of the welded winding and the second welded winding, Figure 3 shows the external output characteristic curves of the weak current region and the strong current region, and Figure 4 shows the external output characteristics of the AC auxiliary power supply. It is a curve diagram. DESCRIPTION OF SYMBOLS 1... First welding winding, 2... Second welding winding, 3... Output current adjustment device, 4, 5... Output terminal, 6... Phase control device, 7... Rectifier, 8... …
Strength/weakness switch, 9...Outlet, 10...
...Maximum characteristic curve in the weak current region, 11... Characteristic curve of the second welded winding, 12... Minimum characteristic curve in the weak current region, 13... Characteristic curve of the AC auxiliary power supply,
14... Overlapping region, 15... Minimum characteristic curve in the strong current region, 16... Maximum characteristic curve in the strong current region.

Claims (1)

[Scope of utility model registration request] The output windings of the welding generator include a first welding winding for a weak current region that is electrically independent from each other, and a strong welding winding having a smaller number of turns to set the maximum output lower than the first welding winding. and a second welding winding for the current region, and an output current adjustment device comprising a thyristor and a diode that performs full-wave rectification and adjusts the welding current is connected to the first welding winding, and the The second welding winding is connected to the output end of the output current adjustment device via a rectifier that performs full-wave rectification and an open/close type strength changeover switch, and the second welding winding is connected to the output end of the output current adjusting device. An output control device for a welding generator, characterized in that it is connected to a power outlet.