JPS63192565A - Welding machine - Google Patents

Abstract

PURPOSE:To simply use a household plug socket as a power source by detecting an output current at the time of welding and providing a current relay to close the output current to a contact point inserted between the capacitor winding and a capacitor. CONSTITUTION:The titled welding machine is provided with a leakage magnetic path 3 between the winding P of AC input terminals 1 and 1' and the winding S of output terminals 2 and 2'. Further, the output contact point 4 to act by the current relay CRY through a current transformer CT is provided between the capacitor winding T of a transformer TR for welding and a capacitor C for improving the power factor. At the time of welding, when the output current is detected by the current transformer CT, the contact point 4 is immediately turned on by an action of the relay CRT and the capacitor C is connected with the winding T. At this time, an AC input current is remarkably reduced by setting the capacitor C to a proper value. In this way, the welding machine which can simply use the household 100V plug socket as the power source is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field This invention belongs to the technical field of providing a welding machine that can be easily used with a household 100V outlet as a power source.

(B) Prior Art FIG. 3 is a circuit diagram showing the configuration of a conventional welding machine, and FIG. 4 shows its output voltage and current characteristics.

(c) Problems to be solved by the invention In the conventional welding machine, 1 and 1' are AC input terminals, 2.2
' is an output terminal, 3 is a one-cage magnetic path inserted between the primary winding P and the secondary winding S, and Figure 4 shows the rated input voltage applied to the input terminal of the welding machine shown in Figure 3. Output voltage V when
o Shows the relationship between the output current Io and Voo is the no-load output voltage,
Ios is the short circuit output current. Therefore, in conventional welding machines, in order to maintain good arc characteristics during welding machine operation by inserting a leakage magnetic path 3, the output voltage and current characteristics are specified as shown in Figure 4, and the no-load Output voltage V
oo is approximately 60V, and short circuit output current Ios is approximately 60A.

Therefore, if the input power when operating the welding machine exceeds 3KVA and the AC input is 100V, the input current will be 30A or more, which is about twice the allowable current of 15A for a household 100V outlet, and the household outlet will be used as a power source. It had problems such as being unsuitable as a welding machine. Therefore, especially in order to use a welding machine at home, it is usually necessary to add a special 200V power source.

(d) Means for solving the problems The purpose of the present invention is to solve the above problems and provide a welding machine that can be easily used with a household 100V outlet as a power source. The configuration is a welding machine that includes an AC input terminal and input winding, a welding machine output terminal and output winding, a leakage magnetic path provided between the input winding and the output winding, a capacitor winding, and a capacitor. , the AC input current during welding machine operation is significantly reduced by providing a current relay in the circuit to detect the output current during welding and close the contact inserted between the capacitor winding and the capacitor. This will be explained with reference to FIG. 1, which is an embodiment of the present invention. Since the same symbols as those in the configuration diagram of FIG. 3 described above indicate the same components, they will be omitted, and only components unique to the present invention will be explained here.

In Figure 1, T is the tertiary winding (capacitor winding) of the welding transformer TR, C is the power factor correction capacitor, CT
4 is a current transformer for detecting the welding machine output current I, CRY is a current relay operated by the current transformer CT, and 4 is an output contact that is turned ON by the operation of the current relay CRY.

(E) Function Next, the function of the welding machine of the present invention will be explained. When the welding machine is in a rest state, output terminal 2.2' is in an open state, the output current ■0 is zero, and the current relay CRY is OFF.
Since the power factor correction capacitor C is disconnected from the tertiary winding (capacitor winding) T, a small amount of the no-load excitation current of the welding transformer TR flows through the primary winding P. Only. However, when electric welding is started by output terminal 2.2', the output becomes almost short-circuited, and the output current IO also shows a value close to the short-circuited output current 1os, the current relay CRY operates through the current transformer CT, and the contact 4 Turn on immediately
Therefore, the power factor improving capacitor C is connected to the tertiary winding (capacitor winding) T.

(F) Embodiment The transformer used in the conventional welding machine shown in FIG. 3 shows a significant lag in input power factor during operation due to the insertion of the leakage magnetic path 3. In the example shown in FIG. 1, the power factor is significantly improved by the function of the power factor improving capacitor C during operation of the welding machine. −
Since the relationship between the force output voltage VO and the output current 1o is determined by the leakage magnetic path 3, it is exactly the same as the characteristics shown in FIG. 4, and the welding characteristics do not change.

According to experiments, by selecting the most appropriate value for the power factor correction capacitor C, the AC input current during operation of the welding machine can be reduced to 13 to 14 A even when using a household 100 V outlet as the power source. It has been proven that it is possible to limit the power consumption, and it has become technically possible to create a welding machine powered by a household 100V outlet.

Next, FIG. 2 is a circuit diagram showing the configuration of another embodiment of the present invention. To explain the difference from the previous embodiment, 4' is a semiconductor switch operated by the output signal of the current relay CRY, and its operation is as follows. The semiconductor switch 4' is turned on by the output signal of the current relay CRY, which is activated by the output current 0 flowing when welding is started, and the power factor correction capacitor C is connected to the tertiary winding. Therefore, in the embodiment shown in FIG. 2 as well, as in FIG. 1, the power factor of the input power source is significantly improved, and a household 100V outlet can be used as a power source welding machine.

(G) Effects of the Invention The welding machine of the present invention configured with the above circuit requires special wiring when using a conventional household outlet (maximum allowable current 15A), but this additional work is unnecessary. This makes stable welding possible, and its industrial value is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of the welding machine of the present invention, FIG. 2 is a circuit diagram of another embodiment of the present invention, FIG. 3 is a circuit diagram of a conventional product, and FIG. 4 is an output voltage of the conventional product. Shows the characteristics of output current. 1.1' - Input terminal 2.2' - - - Output terminal 3 - - - - - - Leakage magnetic path 4 - -
---1-------- Output contact 4 of current relay CRY
' ---1--- Semiconductor switching element CRY operated by the output signal of current relay CRY --- Current relay T R--------- Transformer P---1 --- −・−Manual winding s −−−−−
---・-------One output winding T--Capacitor winding C--------One--Capacitor CT--One--Current transformer

Claims (2)

[Claims] (1) In a welding machine equipped with an AC input terminal and input winding, a welding machine output terminal and output winding, a leakage magnetic path provided between the input winding and the output winding, a capacitor winding, and a capacitor. By installing a current relay to detect the output current during welding and close the contact at the contact inserted between the capacitor winding and the capacitor, the AC input current during welding machine operation can be reduced. Characteristic welding machine. (2) The welding machine according to claim 1, in which a semiconductor element is used as a contact point inserted between a capacitor winding and a capacitor winding to detect an output current during welding.