Contenido

Las fuentes de alimentación de soldadura que se ven con más frecuencia se pueden clasificar dentro de los siguientes tipos:.

Transformer

A transformer-type welding power supply converts moderate voltage and moderate current electricity from the utility grid (typically 230 or 115 VAC) into a high current, low voltage supply, typically between 17 and 45 (open circuit) volts and 55 to 590 amps. A rectifier converts AC to DC in more expensive machines.

This design typically allows the welder to select the output current by variously moving a primary winding closer or further away from a secondary winding, moving a magnetic shunt in and out of the transformer core, using a series saturation reactor with a variable saturation technique in series with the secondary current output, or simply allowing the welder to select the output voltage from a set of taps on the secondary winding of the transformer. These transformer style machines are usually the least expensive.

The trade-off for reduced cost is that pure transformer designs are often bulky and massive because they operate at the mains frequency of 50 or 60 Hz. These low-frequency transformers must have high magnetizing inductance to avoid wasteful shunt currents. The transformer may also have significant leakage inductance for short circuit protection in case a welding rod sticks to the workpiece. The leakage inductance can be variable so that the operator can set the output current.

Generator and alternator

Welding power supplies may also use generators or alternators to convert mechanical energy into electrical energy. Modern designs are usually powered by an internal combustion engine, but older machines may use an electric motor to drive an alternator or generator. In this configuration, utility power is first converted to mechanical energy and then back to electrical energy to achieve the transformer-like step-down effect. Because the generator output can be direct current, or even higher frequency AC, these older machines can produce DC from AC without the need for rectifiers of any kind, or can also be used to implement variations previously used in so-called Heliarc welders (more often now called TIG), where the alternator avoids the need for an additional higher frequency module box by simply producing higher frequency AC current directly.

Investor

Since the advent of high power semiconductors such as the insulated gate bipolar transistor (IGBT), it is now possible to build a switched mode power supply capable of coping with the high loads of arc welding. These designs are known as inverter welding units. They usually first rectify the AC power from the utility grid to DC; They then switch (invert) the DC power in a step-down transformer to produce the desired welding voltage or current. The switching frequency is typically 10 kHz or higher. Although high switching frequency requires sophisticated components and circuitry, it dramatically reduces the volume of the step-down transformer, as the mass of magnetic components (transformers and inductors) required to achieve a given power level decreases rapidly as the operating (switching) frequency increases. Inverter circuits can also provide functions such as power control and overload protection.

The IGBTs in an inverter machine are controlled by a microcontroller, so the electrical characteristics of the welding power can be changed by software in real time, even cycle by cycle, rather than making changes slowly over hundreds, if not thousands of cycles. Typically, the controller software will implement features such as welding current pulses, providing variable current ratios and densities throughout a welding cycle, allowing variable sweep or stepping frequencies, and providing the time needed to implement automatic spot welding; All of these features would be prohibitively expensive to design on a transformer-based machine, but only require program memory space on a software-controlled inverter machine. Similarly, it is possible to add new functions to a software-controlled inverter machine if necessary, through a software upgrade, rather than having to purchase a more modern welder.

Other types

There are also additional types of welders, in addition to the types that use transformers, motor/generator, and inverters. For example, laser welders also exist, and they require a completely different type of welding power supply design that does not fall into any of the welding power supply types discussed above. Likewise, spot welders require a different type of welding power source, typically containing elaborate timing circuits and large banks of capacitors not commonly found with any other type of welding power source.

Contenido

Las fuentes de alimentación de soldadura que se ven con más frecuencia se pueden clasificar dentro de los siguientes tipos:.

Transformer

A transformer-type welding power supply converts moderate voltage and moderate current electricity from the utility grid (typically 230 or 115 VAC) into a high current, low voltage supply, typically between 17 and 45 (open circuit) volts and 55 to 590 amps. A rectifier converts AC to DC in more expensive machines.

This design typically allows the welder to select the output current by variously moving a primary winding closer or further away from a secondary winding, moving a magnetic shunt in and out of the transformer core, using a series saturation reactor with a variable saturation technique in series with the secondary current output, or simply allowing the welder to select the output voltage from a set of taps on the secondary winding of the transformer. These transformer style machines are usually the least expensive.

The trade-off for reduced cost is that pure transformer designs are often bulky and massive because they operate at the mains frequency of 50 or 60 Hz. These low-frequency transformers must have high magnetizing inductance to avoid wasteful shunt currents. The transformer may also have significant leakage inductance for short circuit protection in case a welding rod sticks to the workpiece. The leakage inductance can be variable so that the operator can set the output current.

Generator and alternator

Welding power supplies may also use generators or alternators to convert mechanical energy into electrical energy. Modern designs are usually powered by an internal combustion engine, but older machines may use an electric motor to drive an alternator or generator. In this configuration, utility power is first converted to mechanical energy and then back to electrical energy to achieve the transformer-like step-down effect. Because the generator output can be direct current, or even higher frequency AC, these older machines can produce DC from AC without the need for rectifiers of any kind, or can also be used to implement variations previously used in so-called Heliarc welders (more often now called TIG), where the alternator avoids the need for an additional higher frequency module box by simply producing higher frequency AC current directly.

Investor

Since the advent of high power semiconductors such as the insulated gate bipolar transistor (IGBT), it is now possible to build a switched mode power supply capable of coping with the high loads of arc welding. These designs are known as inverter welding units. They usually first rectify the AC power from the utility grid to DC; They then switch (invert) the DC power in a step-down transformer to produce the desired welding voltage or current. The switching frequency is typically 10 kHz or higher. Although high switching frequency requires sophisticated components and circuitry, it dramatically reduces the volume of the step-down transformer, as the mass of magnetic components (transformers and inductors) required to achieve a given power level decreases rapidly as the operating (switching) frequency increases. Inverter circuits can also provide functions such as power control and overload protection.

The IGBTs in an inverter machine are controlled by a microcontroller, so the electrical characteristics of the welding power can be changed by software in real time, even cycle by cycle, rather than making changes slowly over hundreds, if not thousands of cycles. Typically, the controller software will implement features such as welding current pulses, providing variable current ratios and densities throughout a welding cycle, allowing variable sweep or stepping frequencies, and providing the time needed to implement automatic spot welding; All of these features would be prohibitively expensive to design on a transformer-based machine, but only require program memory space on a software-controlled inverter machine. Similarly, it is possible to add new functions to a software-controlled inverter machine if necessary, through a software upgrade, rather than having to purchase a more modern welder.

Other types

There are also additional types of welders, in addition to the types that use transformers, motor/generator, and inverters. For example, laser welders also exist, and they require a completely different type of welding power supply design that does not fall into any of the welding power supply types discussed above. Likewise, spot welders require a different type of welding power source, typically containing elaborate timing circuits and large banks of capacitors not commonly found with any other type of welding power source.