What is DC reverse connection and forward connection, the difference between DC forward connection a

1. The positive connection method refers to a wiring method used to measure the dielectric loss factor in the loop test of Xilin bridge. The positive connection method measures the dielectric loss due to a small value, and the reverse connection method measures the dielectric loss due to a large value.

2. In tungsten argon arc welding, DC reverse connection has the effect of removing the oxide film, which is called "cathodic crushing" or "cathodic atomization". The effect of removing the oxide film also exists in the reverse polarity half-wave of AC welding, which is an important factor in the successful welding of aluminum, magnesium and their alloys.

Practice has proved that when DC is reversed, the oxide film on the surface of the workpiece can be removed under the action of the arc to obtain a bright and beautiful weld with a well-formed appearance. This is because the work of metal oxide escape is small and it is easy to emit electrons, so it is easy to form cathode spots and produce arcs on the oxide film, and cathode spots have the property of automatically looking for metal oxides.

When operated with a DC welder, there are fixed positive and negative electrodes at the output end of the power supply. The wiring method of connecting the weldment to the positive electrode of the power supply and the electrode to the negative electrode of the power supply is called positive connection; The wiring method in which the weldment is connected to the negative electrode of the power supply and the electrode is connected to the positive electrode of the power supply is called reverse connection.

# p/ h.A Q B9 E7 Y AC welding power supply does not have polarity problems due to the continuous alternation of positive and negative poles.

4 a( t: b3 `1 y"Q8 g z% y ( c* y when the forward connection and the reverse connection, the shape of the welding arc is different. Principle of selection of polarity of weldments:

h+ f3 t! j+ n"H W8 x0 A8 x 1, when alkaline low-hydrogen electrode is used for electrode arc welding, reverse connection is used. If the positive connection is used, the arc combustion is unstable, the arc sound is very violent, it emits a strong hissing sound, the splash is large, and it is very easy to produce pores.

When using acid electrodes, the polarity has little effect on the stable combustion of the arc r8 m3 b& w% e- q! s# n

In the same way, if the submerged arc welding is welded with a DC power supply, reverse connection is generally used. ( 1 ~1 x; y" x. [

2. When tungsten argon arc welding steel and brass, positive connection is used. Because the heat generation of the cathode is much smaller than that of the anode, when the DC positive connection power supply is used, the tungsten electrode is connected to the negative electrode, the heat generation is small, it is not easy to overheat, the tungsten electrode has a long life, and the tungsten electrode of the same diameter can use a larger welding current. At the same time, when the weldment is connected, the heat of the anode is large, so the penetration depth is large and the productivity is high.

What are DC Forward and DC Reverse Connection? What are the 4 benefits of their connection? 1 trick to teach you to remember forever.

The difference between DC forward and reverse DC is as follows:

1. The heat distribution of the direct disturbance current is 70% of the workpiece and 30% of the electrode; The heat distribution of DC reverse connection is 30% of the workpiece and 70% of the electrode.

2. The weld bead of DC forward connection is deep and narrow, and the weld bead of DC reverse connection is shallow and wide, which can remove oxides.

3. The heat generated by DC positive connection is high, which is convenient for welding thick components, and is often used for steel welding; DC reverse coupling is usually suitable for oxide welding.

The principle of reverse DC connection:

When DC is reversed, the oxide film on the surface of the workpiece can be removed under the action of the arc to obtain a bright and beautiful weld with a well-formed appearance.

This is because the metal oxide has a small escape work and is easy to emit electrons, so it is easy to form cathode spots and produce arcs on the oxide film, and the cathode spots have the property of automatically looking for metal oxides.

The cathode spot has a high energy density and is hit by a very massive positive ion, which breaks the oxide film.

1. Positive connection: DC means that the workpiece is connected to the positive electrode, and the welding rod is connected to the negative electrode. The temperature of the workpiece at the positive electrode is high, the penetration depth is deep, the pressure of the droplet spot is large, the possibility of spatter is large, and the arc is unstable, so the positive connection is rarely used.

2. Reverse connection: DC reverse connection means that the workpiece is connected to the negative electrode, and the welding rod is connected to the positive electrode. In this way, the welding machine is connected, the arc is stable, the spatter is less, and the forming is beautiful, and this access method is generally used.

It depends on the specific situation.

DC reverse connection: the welding handle is connected to the positive pole +, and the ground wire is connected to the negative pole -.

DC positive connection: solder handle to the negative pole - ground wire to positive pole +.

DC reverse connection, the characteristics are as follows:

The spatter is minimal and the arc is stable.

Suitable for all acid and alkaline electrode welding.

The penetration depth is shallow, suitable for welding thin parts.

Less slag inclusion and less porosity.

It depends on the specific situation.

DC reverse connection: the welding handle is connected to the positive pole +, and the ground wire is connected to the negative pole -.

DC positive connection: solder handle to the negative pole - ground wire to positive pole +.

DC reverse connection, the characteristics are as follows:

The spatter is minimal and the arc is stable.

Suitable for all acid and alkaline electrode welding.

The penetration depth is shallow, suitable for welding thin parts.

Less slag inclusion and less porosity.

The main differences are in the applicable situations, different welding methods, and different characteristics. 1. The applicable situations are different: the reverse connection of DC welding machine is usually used to weld thin plates, non-ferrous metals, and stainless steel; Positive bonding is usually used to weld thick plates to achieve maximum penetration.

2. Different welding methods: when DC is positively connected, the workpiece is connected to the positive electrode; When using reverse DC connection, the electrode is connected to the anode. <

1. The applicable situation is different: the reverse connection of the DC welding machine is generally used to weld thin plates, non-ferrous metals and stainless steel. The DC welding machine is connected to the general welding thick plate to obtain a large penetration depth.

Of course, DC reverse connection is also possible, but for thick plate root welding with grooves, DC reverse connection is still better. Alkaline electrodes are generally reversed DC to reduce porosity and spatter.

2. Different welding methods: when DC is positively connected, the workpiece is connected to the positive electrode; When using reverse DC connection, the electrode is connected to the anode.

3. The characteristics are different: when DC is used, the temperature of the anode area is higher than that of the cathode area, so the workpiece has a large penetration depth and the welding rod melts slowly. When DC reverse connection is used, the electrode is connected to the anode, and the electrode melts faster, while the workpiece has a smaller penetration depth, and the arc is relatively stable, and it is not easy to produce hydrogen porosity.

1. In the welding process, the two poles of the arc welding machine are connected to the welding rod and the weldment respectively, forming a complete welding circuit.

2. For DC welding machines, one is extremely positive, and the other is extremely negative. When the weldment is connected to the positive electrode and the welding tong (electrode) is connected to the negative electrode, it is called the positive connection method (referred to as the positive connection), and the reverse connection method is called the reverse connection method (referred to as the reverse connection).

3. For AC welding machine, because the polarity of the power supply is alternating, there is no problem of forward connection and reverse connection.

4. Forward connection is + grounding wire, - welding handle. Reverse connection is - grounding wire, + welding handle.

What are DC Forward and DC Reverse Connection? What are the 4 benefits of their connection? 1 trick to teach you to remember forever.