Welding power supply

A welding power source used to generate the required for the high electric arc welding current. The simplest welding power source is a welding transformer in the form of a short-circuit proof leakage transformer which supplies alternating current. When welding power sources which supply direct current, this transformer is supplemented with a rectifier.

Electronic welding power sources, these are special forms of inverters which are also referred to as welding inverters, do not need a high-reactance transformers but use technical procedures as in a switching power supply.

Welding transformer

The welding transformer the alternating current of the network is converted by high voltage and low current into an alternating current at low voltage and high current as required for welding. The control of the welding current are controlled by taps on the primary of the power transformer. Often a movable yoke between the secondary and the primary coil is mounted, whereby a stepless regulation. Its current output is similar to a constant current source, which holds the set current with varying load almost constant.

Welding rectifier

A welding rectifier converts the three-phase alternating current ( phase current) to DC power for welding.

It consists of a power transformer and a downstream rectifier block. The rectifier block converts the alternating current into direct current. The ripple is mainly determined by the rectifier type. Through the use of three-phase ( three-phase arrangement ) ripple ( single-phase arrangement ) can be reduced to about 4 % compared to almost 50 % in alternating current. The downstream smoothing reactor is used to reduce the ripple and decisively determines the welding properties, eg the ignition of the arc and spatter.

Welding converter

Welding converter comprised of an electric motor, typically operated by a three phase alternating current which drives a controllable direct-current generator through a shaft. These devices were built mainly in the time, was not yet available as a high-performance electronics. Converters were characterized by a low harmonic content, but they are prone to failures and maintenance- intensive than welding rectifier by the mechanical components. With emerging power electronics, these devices disappeared from the market. However, they talked for some time on the top power or current class. Welding converter are used almost exclusively with decreasing U / I characteristic of the electrode manual welding. By rotating components, these devices are louder than modern welding rectifier. In addition, their efficiency is relatively low ( max 60%).

In addition to pure converters, there are combination devices where either the generator is driven by an electric motor or an internal combustion engine. They are designed for use on construction sites and can be operated IC engine with inadequately sized power supply. Here, however, they are louder than in electric mode.

Not to Schweißumformern devices are those in which the generator is operated solely IC engine, as this violates the definition of a transformer. However, they are often referred to colloquially as converters.

Combustion power driven welding power sources

For use on construction sites, in which there is no or insufficient power supply, there is a combustion engine -driven welders. For them, an internal combustion engine, for bulky appliances drives almost always on a diesel, a generator. Almost always a DC generator is used, which is by its falling characteristic for MMA welding. Due to the internal combustion engine, the devices are very noisy.

In addition, generators are on the market, which are not only the mains voltage of 230 /400 V connection even with lower voltage and adjustable current for welding.

Welding Inverter

The welding inverter is an electronic welding power source. Inverter welding machines are built for all arc welding processes such as electrodes, GMAW, Plasma and WIG / TIG welding. The devices are connected to one or three phase depending on the power to the power grid. The basic principle of an inverter corresponds to a switching power supply. The mains voltage is first rectified, chopped with the aid of power semiconductors with a frequency between 20 kHz and 150 kHz, and a relatively small transformer is transformed to a lower voltage. Then the welding current with the aid of suitable diode must be rectified. The size of transformers same power is approximately inversely proportional to their working frequency, ie, the transformer and the entire welding machine, the higher the frequency, the smaller and lighter can be built. The efficiency of inverter welding equipment is better than other power sources. Due to the higher operating frequency strong dynamic welding processes can be much better controlled. In addition, several convenience functions are implemented:

• Arc welding
• Welding tool
• Electric machine