JPH0349806Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention relates to a two-stage remote control device for an engine-driven DC welding machine, and in particular, it enables fine adjustment of welding output in all current ranges, and This invention relates to a two-stage remote control device that improves welding work in the current range.

[Conventional technology]

Conventionally, a welding machine has a circuit shown in FIG.
In other words, 21 is the output of the AC auxiliary generator (110V
AC output), 22 is a single-layer full-wave rectifier, and is applied to the excitation coil 25 by changing the resistance value of the variable resistor 24a in the current remote fine adjuster 24 by switching the changeover switch 23. The welding output is obtained by controlling the amplitude of the voltage and switching the DC output via the rectifier 27 of the generator 26 with the welding current switch 28. FIG. 5 shows the static characteristics of the welding machine, and in the same figure, by switching the welding current switch 28,
For example, when tap T ₁ is set, a strong current range between A ₄ and _{B 4} can be selected by adjusting the variable resistor 24a, and when tap T ₄ is set, a strong current range between A ₁ and B ₁ can be selected. Welding current in the weak current range can be selected.

As mentioned above, when welding work is performed at a location away from the welding machine, the variable resistor that adjusts the excitation current of the welding generator is extended to the hand via a cable and controlled remotely.

In this case, the following inconveniences occurred.

Since the excitation current of the generator is directly controlled, the capacity of the variable resistor becomes large, resulting in large size and heat problems.

Since the excitation current of the generator is directly controlled, the relationship between the rotation angle of the variable resistor and the welding current forms a saturation curve in proportion to the excitation characteristics of the generator, as shown in FIG. Therefore, fine adjustment can only be made in a certain range, and the welding current changes greatly in the linear part of the characteristic curve in response to a change in slide resistance, but the change is small as it approaches the saturated part of the characteristic curve, so the variable resistor is used. Even if the welding current is moved even slightly, the welding current changes significantly, which is very inconvenient when performing advanced welding work such as pipe work.

In all ranges of welding output, it is difficult to finely adjust the current from strong to weak just by operating the variable resistor included in the remote control device. operated and operated remotely. Therefore, each time the welding conditions change, it is necessary to return to the main body of the machine and operate the welding current switch, which is inefficient.

The following techniques have been implemented as a method to solve the above drawbacks.

As a solution to this problem, the variable resistor can be made smaller by adopting a thyristor control method.

As a solution, a variable resistor for fine current adjustment is connected in series with a variable resistor for current adjustment, and the welding current is finely adjusted in front of the second stage.

As a solution to this problem, as in the thyristor control method proposed in Japanese Patent Application No. 58-230509, a rotary switch has a plurality of variable resistors connected in a uniaxial structure, and further has a multistage circuit that selects the variable resistors according to welding conditions. When a remote control box is equipped with a welding current switch for remote control, the welding current switch included in the welding machine is set to the high tap, allowing remote control of all welding conditions from the strong current to the weak current range.

[Problem that the invention attempts to solve]

However, the prior art remote control device with the above-mentioned solution has the following drawbacks and is not suitable for the actual situation. That is, it is very expensive because it includes a plurality of variable resistors and a rotary switch. Also,
The biggest drawback is that in welding work with small currents, the maximum current characteristics of the welding machine, that is, the strong tap characteristics shown in Figure 7, can be translated in parallel to the characteristics of the small current range (as shown in VR to VR). characteristics). As a result, the no-load voltage in the small current range becomes extremely low, causing problems in small current operations (less than 50V). In addition, the characteristics shown in the same figure
VR to VR indicate the adjustment range of each variable resistor selected by the rotary switch.

The present invention has been devised in view of the above points, and an object of the present invention is to provide a two-stage remote control device that can increase the no-load voltage in a small current range and is relatively inexpensive.

[Means for solving problems]

The present invention is a two-stage remote control device that controls a DC voltage applied to an excitation coil through a single-phase mixed bridge rectifier in which a thyristor and a diode are bridge-connected. The single-axis dual variable resistor that adjusts the thyristor conduction angle by changing the phase and the switch that switches the resistor to two stages are separated from the welding machine main body to enable remote control, and the welding output can be controlled by a strong tap. It is characterized by being equipped with a welding current switch that can be set in two stages, including a middle tap and a welding current switch.

[Effect]

This invention is equipped with a single-shaft dual variable resistor and a welding current strong/weak switching switch.During welding work, the welding current switching switch can be used to select either a strong tap or a medium tap depending on the welding conditions. It is designed to enable fine current adjustment, especially in the small current range, and to improve the rise of the welding voltage.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an electrical circuit diagram of an embodiment of the present invention. In the figure, 1 is the output of the AC auxiliary generator (110v
(AC output), 2 indicates two thyristors 3
A, 3b and two diodes 4a, 4b are bridge-connected to form a single-phase mixed bridge rectifier, 5 is a pulse generator that outputs pulses to be applied to thyristors 3a, 3b, 6 is an excitation coil of a generator 7, and a single-phase mixed bridge rectifier It is connected to the output of bridge rectifier 2. 8 is a rectifier circuit of the welding generator 7, and the output of the rectifier circuit is a tap T ₁ which takes out the welding output of strong current and medium current.
_T2 is provided, and the output of the welding current is switched by operating a switch 9.

Reference numeral 10 includes a variable resistor 12 connected in series with a variable resistor 11 and a fixed resistor 15, a single-shaft double variable resistor 13 having a predetermined rotation angle, and a variable resistor 11 of the single-shaft double variable resistor 13. , 12 is a remote regulator having a changeover switch 14 having a terminal connected to one end of each of the switches.

The single-axis dual variable resistor 13 is connected to each variable resistor 1.
By changing the resistance values of thyristors 1 and 12 and applying pulses from the pulse generator 5 to the thyristors 3a and 3b, the conduction angles of the thyristors 3a and 3b are finely adjusted. The changeover switch 14 selects one of the single-axis dual variable resistors 11 and 12 and selects the thyristor 3.
The conduction phase width of a and 3b is selected.

Next, the action will be explained.

In this embodiment, the magnitude of the welding current is selected by a welding current switch 9 provided on the welding current output side. In addition, in Fig. 2 a and b, β ₁ and β ₂ are thyristors 3a,
3b indicates the firing setting position, and α ₁ and α ₂ indicate the firing end position. The ignition end positions α ₁ and α ₂ are determined by the resistance values of the resistors 11 and 12 shown in FIG. Also, the amount of change in the resistance value of the variable resistor 11 is determined by the amount of change in the resistance value of the variable resistor 11.
The conduction phase width of the thyristors 3a and 3b is determined between α ₁ and β ₁ in FIG. 2a, and the conduction phase width of the variable resistor 12 is similarly determined for the thyristors 3a and 3b.
Therefore, by switching the changeover switch 14 to select each of the variable resistors 11 and 12, it is possible to perform the same function as the welding current switch 28 installed in the conventional generator shown in FIG. can. Therefore, the straight line 31 in the characteristic curve shown in FIG. 3 represents the characteristic when the welding current switch 9 is set to the strong tap _T1 . Regarding the welding current adjustment range, since either the variable resistor 11 or 12 is selected from the single-axis dual variable resistor 13 by operating the changeover switch 14, when the strong tap _T1 of the welding current switch 9 is selected, When the MAX terminal of the changeover switch 14 is selected, it is possible to adjust the welding current between the straight line 31 and the straight line 32 shown in FIG.
The welding current is strong between _T1 and straight line 34.
This is the welding current adjustment width when the changeover switch 14 is at the MIN terminal, and since there is a fixed resistor 15, it overlaps with the straight line 32. The range from straight line 35 to straight line 36 is the welding current adjustment width when the welding current is at tap _T2 and the changeover switch 14 is at the MAX terminal. Also, from straight line 37 to straight line 3
8 shows the welding current adjustment width when the welding current is at tap _T2 and the selector switch 14 is at the MIN terminal.

As shown in the above experimental data, in this example, by using the medium tap T ₂ of the welding current switch provided in the machine body, the slope of the welding characteristics is changed from that when using the strong tap T ₁ . By making it larger, it was possible to significantly increase the no-load voltage especially in welding work in a small current range, and it was possible to obtain excellent welding characteristics.

[Effect of idea]

As explained above, the present invention controls the phase of the voltage applied to the excitation coil of the welding generator by operating a single-axis dual variable resistor and a two-circuit changeover switch, making it easy to switch the current width at the welder's hand. It is possible to precisely and finely adjust the welding current. In addition, since the pulse for controlling the phase of the thyristor is controlled by a variable resistor and a changeover switch, it is small, lightweight, inexpensive, and convenient to carry as a remote control device. Furthermore, in welding work in a small current range, which was considered to be the biggest drawback of conventional technology, the no-load voltage can be significantly increased in welding work in a small current range by switching the welding current switch in the main body of the machine in two steps. , welding performance can be improved, welding work efficiency is good, and workability and economical efficiency are dramatically improved compared to conventional equipment.

[Brief explanation of the drawing]

Fig. 1 is an electric circuit diagram of the embodiment of the present invention, Fig. 2 is an explanatory diagram of the operation of welding current width adjustment of the embodiment of the invention, Fig. 3 is a static characteristic diagram of the embodiment of the invention, and Fig. 4 is a diagram of the conventional An electrical circuit diagram of a remote control device for an engine-driven welding machine, Fig. 5 is a static characteristic diagram of the conventional method shown in Fig. 4, and Fig. 6 is a characteristic diagram of the rotation angle and welding current of a variable resistor of the conventional method. FIG. 7 is a static characteristic diagram of one method used conventionally. 1... Output of AC auxiliary generator, 2... Single-phase mixed bridge rectifier, 3a, 3b... Thyristor, 4
a, 4b...diode, 5...pulse generator,
6... Excitation coil, 7... Welding generator, 8...
Rectifier circuit, 9...Switcher, 10...Remote adjuster, 11, 12...Variable resistor, 13...Single axis dual variable resistor, 14...Switching switch.

Claims (1)

[Scope of utility model registration request] A two-stage remote control device that controls a DC voltage applied to an excitation coil via a single-phase mixed bridge rectifier in which a thyristor and a diode are bridge-connected, the device comprising: a pulse generator that controls the phase of the thyristor; and a pulse generator that controls the phase of the thyristor. A single-shaft double variable resistor that adjusts the thyristor conduction angle by changing the pulse phase of the generator, a switch that switches the single-shaft double variable resistor into two stages, and a switch that changes the welding output to a strong tap and a medium tap. and a welding current switching device that is set in two stages, and the single-axis dual variable resistor and a switch that switches the resistor to two stages are separated from the welding machine main body and configured to be remotely controllable. Staged remote control device.