What is the voltage of the welding machine? What is the current? What is the working principle?

Voltage and current of welding machine:

Ordinary welding machines have current regulators, which are about 50 to 600 amps. The output voltage is divided into no-load voltage and working voltage. No-load voltage refers to the voltage when the welding machine is not working, which is about 50 V-70 V High voltage is convenient for arc striking. The working voltage refers to the voltage during normal welding after igniting the arc, which is about 30 V ...?

The magnitude of the current is related to the workpiece to be welded. The greater the thickness of the workpiece, the greater the required current, and vice versa. At the same time, if the current is large, it is easy to ignite the arc. If the thickness of the workpiece is small and the regulated current is large, the workpiece is easy to penetrate.

Working principle of electric welding machine:

The working principle of ordinary welding machine is similar to that of transformer, which is a step-down transformer. The two ends of the secondary coil are the workpiece to be welded and the coated electrode, which ignite the arc and generate a heat source at the high temperature of the arc to weld the gap between the workpiece and the coated electrode.

Welding transformer has its own characteristics, that is, the voltage drops sharply. Covered electrode voltage drops after ignition; When the covered electrode is short-circuited due to adhesion, the voltage also drops sharply. The reason for this phenomenon is the iron core characteristics of welding transformer.

The working voltage of the welding machine can be adjusted not only by a 220/380 voltage conversion, but also by the tap of the secondary coil. At the same time, it can be adjusted by iron core. The more the iron core enters, the smaller the welding voltage will be.

Electric welding principle

In fact, the principle of electric welding is to reduce the voltage of the commonly used 220V or 380V industrial power supply through the voltage reducer in the electric welding machine, enhance the current, and use the huge heat generated by electric energy to melt steel. The integration of coating and covered electrode makes the fusion between steel higher, and the coating on the outer layer of covered electrode plays a very important role.

The covered electrode used in manual arc welding consists of two parts: the coating and the flux core. When welding, the electrode, as an electrode, on the one hand plays the role of conducting current and initiating arc, so that a continuous and stable arc is generated between the electrode and the base metal, providing necessary heat for melting welding.

On the other hand, covered electrode, as a filler metal, is added to the weld and becomes the main component of the weld metal. Therefore, the composition and quality of covered electrode will directly affect the chemical composition, mechanical properties and physical properties of weld metal. In addition, covered electrode has a great influence on the stability of welding process, the appearance quality of weld and welding productivity.

The welding core is the metal core of covered electrode. In order to ensure the weld quality, there are strict regulations on the content of various metal elements in the weld core. In particular, there are strict restrictions on harmful impurities (such as sulfur and phosphorus). ), and the quality of core metal is better than that of base metal.

Without coating, the polished rod covered electrode cannot be arc welded. This is because of poor arc stability, large spatter and poor weld formation. After long-term practice, it is gradually found that coating some mineral raw materials (i.e. coated covered electrode coated) on the core can greatly improve the performance of coated covered electrode.

Electric welding machine is to use the high-temperature arc generated when the positive and negative electrodes are short-circuited, to melt the solder on the electrode and the material to be welded, so as to combine the contacted materials. Its structure is very simple, it is a high-power transformer.

Welding machines can be generally divided into two types according to the types of output power, one is AC power supply and the other is DC power supply. They use the principle of inductance, which will produce a huge voltage change when it is turned on and off, and use the high-voltage arc generated when the positive and negative electrodes are short-circuited instantly to melt the solder on the electrode, thus achieving the purpose of atomic bonding.

Voltage, also called potential difference or potential difference, is a physical quantity to measure the energy difference of unit charge in electrostatic field due to different potentials. Its magnitude is equal to the work done by the unit positive charge moving from point A to point B under the action of electric field force, and the direction of voltage is defined as the direction from high potential to low potential.

The international unit system of voltage is volts (V for short), and commonly used units are millivolts (mV), microvolts (μV) and kilovolts (kV). This concept is similar to the "water pressure" caused by the high and low water level. It should be pointed out that the word "voltage" is generally only used for circuits, while "potential difference" and "potential difference" are generally used for all electrical phenomena.

Divide by size

Voltage can be divided into high voltage, low voltage and safe voltage.

The difference between high voltage and low voltage is based on the voltage value of electrical equipment to ground. The voltage to ground is higher than or equal to 1000 volts. The voltage to ground is lower than 1000 volts.

Among them, safe voltage refers to the voltage that the human body contacts for a long time without the danger of electric shock. According to the national standard "GB3805-83", safe voltage stipulated the voltage series provided by specific power sources to prevent electric shock accidents. China has stipulated the following five grades for power frequency safe voltage, namely, 42V, 36V, 24V, 12V and 6V.