Welding Machines
Welding Machines
Welding is a way of heating pieces of metal using electricity or a flame so that they melt and stick together. There are many kinds of welding, such as arc welding, resistance welding and gas welding. Welding device or welding power supply is a device that provides an electric device to provide power. Welding generally requires high current and it can need about 12,000 amps in case of spot welding. Low current can also be used for welding two razor blades together at 5 amps with gas tungsten arc wielding. A welding power supply can be as simple as a car battery and as sophisticated as a modern silicon controlled rectifier technology with additional logic to assist in the wielding process.
Classification
Welding machines are basically classified as constant current (CC) or constant (CV). The difference between the two is that a constant current machine will vary its output voltage to maintain a steady current while a constant voltage machine will fluctuate its output current to maintain a set voltage. For instance, shielded metal arc welding will use a constant current source and gas metal and gas metal arc welding and flux-cored arc welding typically use constant voltage sources. Constant current is also possible with a voltage sensing wire feeder.
The nature of the CV machine is the above two mentioned as the welder is not able to control the arc length manually. In case an attempt to use a CV machine to weld with shielded metal arc welding then small fluctuation in the arc would cause wide fluctuations in the machines output. With a CC machine the welder can count on a fixed number of amps reaching the material to be welded regardless of the arc distance. Too much distance will cause poor welding and thus proper care should be taken.
Machine designs
Most of the welding devices are of the following form:
Transformer
A transformer style welding machine converts high voltage and low current electricity from the utility into a high current and low voltage, typically between 17 to 45 volts and 190 to 590 amps. This type of machine typically allows the welder to select the output current. It is done by either moving the core of the transformer in and out of the magnetic field or by allowing the welder to select from a set of taps on the transformer. These machines are cheap and can be purchased for hobbyist use.
Generator and alternator
Welding machines may also use generators and alternators for converting mechanical energy into electric energy. These modern machines are usually driven by an internal combustion engine but some machines may also use an electric motor to drive the generator or alternator.
Invertor
Invertor units generally convert utility power to high voltage and store this energy in a capacitor bank. A microprocessor controller then switches this energy into a second transformer as it is needed to produce the required amount of welding current. An inverter-based welding power source is light weight portable and has a superior control pulsed welding process.
These machines are used in various industries for performing various tasks and conveniently stick two metal objects together.