What is an Inverter Welder?

Welding Inverter

Inverter devices for performing manual arc welding are becoming an increasingly popular type of equipment. They are radically different from the usual transformer devices.

Inverter Welders provide a more efficient and reliable way of welding than traditional methods.

It is important to understand what an inverter is, how it works, and its benefits before making the decision to purchase one.

A welding inverter is a device that converts main voltage or generator power into low voltage direct current (DC) output used for arc welding.

This offers greater portability, lighter weight, less energy use and better performance compared to transformer-based machines.

It also allows users to adjust their settings manually or automatically depending on the job they’re working on. This can lead to improved weld quality which saves time and money while avoiding costly mistakes or rework.

Parts of a Welder Inverter

The inverter welder consists of the following main units:

  • Rectifier unit: rectifies the mains voltage.
  • Low pass filter: smooths the rectified mains voltage to eliminate network noise.
  • Inverter: creates a high-frequency alternating voltage (most often over 15-20 kHz).
  • Transformer: lowers the resulting high-frequency alternating voltage to the voltage required for welding.
  • Rectifier unit: rectifies high-frequency alternating voltage;
  • High-frequency filter: smoothes the resulting voltage to reduce the resulting noise.
Image: CWB

Advantages of Inverter Welders

A welding inverter allowed you to achieve the following advantages compared to a transformer or rectifier.

  • Low weight: Due to the increase in voltage frequency, the mass of the transformer required to lower the voltage has significantly decreased. Consequently, the mass of the welding machine has significantly decreased. Therefore, these devices have become mobile and now it is possible to easily move them, and some can even be worn on the shoulder when working.
  • Efficiency Improvement: Modern welding inverters reduce electricity losses by up to 10 times, many inverters are capable of operating from 185 Volts and even lower. The efficiency of such an inverter reaches 90%.
  • Fine parameters Control: Inverter welder uses sophisticated electronic that allows very precise welding parameters selection and thus results in reliable welding quality.

Main features of an Inverter Welder

An Inverter Welder is overall provides many important features for welding applications. Two functions of a welding inverter are most common:

  • Anti-Stick – allows you to avoid “sticking” the electrode during welding. Anti-sticking is triggered when the electrode sticks. It automatically ceases to be supplied with electric current. It begins to arrive only when the electrode is torn away from the metal.
  • Arc force performs a similar task, but already in the process of welding. It significantly reduces the possibility of sticking of the electrode.

Disadvantages of Inverter Welders

Unfortunately, inverter power supplies for welding have not only advantages, but also a very significant drawback – the complexity of repair.

  • Due to the presence of complex elements in electrical circuits, it is extremely difficult to repair a welding inverter at home.
  • It is definitely more expensive than classical transformer analogues.
  • Welding inverters are sensitive to construction dust (especially those containing metal inclusions) and moisture.
  • When using devices of this type, it is necessary to adhere to the operating rules specified in the passport. Their violation can lead to breakdowns and expensive repairs.
  • Also, consider when choosing welding inverters that these devices are single-board and multi-board. Single-board inverters are significantly cheaper, but multi-board ones are lighter and cheaper when repaired.

How to select right welding inverter?

To choose the right welding inverter, it is worth answering a number of questions:

  • Where the device will be used: in the garage, in the country, in the workshop (220 V, 380 V),
  • What thickness of metal you will weld (working diameter of the electrode),
  • Your budget.

Read more: Tips for buying new Welder

Design and operation of Welding Transformer

Classical transformer devices are electrical devices and operate at a frequency of 50 Hz. The parameters of electric current from the household network with a voltage of 220 V are not suitable for welding.

They are transformed using a transformer. To do this, an electric current is fed to the primary winding and magnetizes its composite core.

Image credit: CWB

As a result, an alternating magnetic field occurs, which in turn creates an alternating current in the secondary winding. Its parameters differ from the initial ones: the voltage is 50-90 V, and the current is 100-200 A.

It should be noted at once that the second parameter is not limited to the specified limits. In such devices, the strength of the welding current is regulated mechanically and depends on the number of turns in the secondary winding of the transformer.

Devices of this type have a simple design. They are reliable and inexpensive, but at the same time they are characterized by high power consumption, high weight and dimensions. With their help, it is difficult to ensure good quality seams.

Design and operation of Welding Inverter

Inverter welding machines are no longer electrical, but electronic devices and their work is organized according to other principles.

Alternating current first enters the preliminary or primary rectifier, where, with the help of a diode bridge, it is converted into a direct current with a voltage of 220 V.

Then it is fed into the inverter unit. Here, power transistors and thyristors again convert the current to alternating current, but now its frequency reaches 100 kHz.

Image: Researchgate

In the next step, the current enters the high-frequency transformer. Here the tension decreases and its strength increases.

A high-frequency transformer differs from the classical one not only in design, but also in size. In addition, there is practically no loss of energy for heating.

At the last stage, the current passes through the rectifier, where it is converted into a constant with the parameters required for welding.

In the electronic circuit of welding inverters, control units based on microprocessors are used. They ensure the stable operation of all other nodes of the devices.

Control units instantly respond to the slightest deviations of the welding current parameters from the specified ones and correct them. This ensures stable arc burning and good weld quality even with minimal welding experience.

In addition to this, inverter devices have a very wide range of welding current control, provide low metal splashing and allow the use of any type of electrodes. In addition, they are lightweight, compact and as easy to use as possible. All devices are equipped with several protection systems that disable them in case of overheating or overload, and welding with their help can be carried out in any spatial position.

Welding Inverters for domestic Use

All welding inverters on the market can be divided into two large groups:

  1. Household use and
  2. Industrial use.

The first are powered from a conventional household network with a voltage of 220 V and have a maximum welding current of no more than 200 A. They are designed for operation with a low load.

Professional industrial inverters are most often connected to a three-phase network with a voltage of 380 V. As a rule, they have a higher value of the maximum welding current – up to 500 A.

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