Ac welder is also called arc welding transformer. It is a special kind of step-down transformer. It is composed of step-down transformer, impedance regulator, handle and welding arc.In order to make the welding smooth, the transformer power supply can be made according to the welding process.
1. Ac welder has the characteristic of high voltage drop
Generally, the voltage of the power supply shall not vary with the load, and its voltage is constant, such as 380V (single phase) or 220V.While connected to the welding transformer voltage is certain, such as 380 v or 220 v, but after the transformer output voltage can change along with the change of output current (load), and increases with the load voltage and reduce rapidly, this is called a steep fall or decline characteristics.This ADAPTS to the various voltage requirements required for welding:
(1) primary voltage: the external voltage connected to the welder.Because the voltage of the primary coil of the arc welding transformer is single item 380V, the voltage of ac welder connected to the power grid is 380V.
(2) zero voltage: in order to ensure the frequent short circuit welding process, welding rod and welding pieces of contact, the required voltage automatically dropped to near zero, to limit the short circuit current is not infinite and burned the power supply.
(3) no-load voltage: in order to meet the need of arc and safety, the no-load voltage is about 60 ~ 80V, which can both smooth the arc and be safe for the person.
(4) working voltage: after welding the arc, the required voltage can be automatically reduced to the voltage required for the normal work of the arc, which is the working voltage, which is about
20 ~ 40V, this voltage is also safe voltage.
(5) arc voltage: the voltage at both ends of the arc, which is within the working voltage range.When welding, the length of arc will change: the arc length is long and the arc voltage should be higher;Arc length is short, the arc voltage should be lower.Therefore, arc welding transformer should adapt to the change of arc length and ensure the stability of arc.
2. Ac arc welder with welding current can be accommodative in order to adapt to different material and thickness of the welding requirement, the welding current to from dozens of ampere several hundred amperes, and according to the thickness of the workpiece and the electrode diameter is adjusted for the size of the current value.The adjustment of the current generally divided into two levels: level 1 is coarse, commonly used to change the output of thread method (Ⅰ connection or Ⅱ location connection), so as to change the internal coil turns to realize a wide range of current regulation, coarse adjustment shall be carried out under the condition of the cut off power supply, in order to prevent electric shock damage;Another level is fine tuning, commonly used changes "movable core" of the welding machine (dynamic core type) or "moving coil" (position of the moving coil) to achieve the required current value, the operation of the fine adjustment is accomplished by rotating the handle, current value increases, when the handle is counterclockwise current decreases when the handle clockwise, fine adjustment should be performed under no-load condition.The range of coarse adjustment and fine tuning of various types of welder can be used to check the instructions on the sign.