Inductance in Welding

When welding, not only current and voltage affect the result, but also the dynamic behaviour of the arc.
An important role is played by the so-called inductance. It affects how “hard” or “soft” the arc responds and how the welding process feels.

What does inductance mean in welding?

Inductance describes how quickly the welding current changes during short circuits in the arc.
In MIG/MAG welding, there are constant brief interruptions of current when the wire touches the weld pool. Inductance influences how abruptly or smoothly the machine responds to these current changes.

Simply put:
Inductance determines whether the arc works hard and directly or soft and smoothly.

How does inductance affect the welding process?

Depending on the set inductance, the welding behaviour changes noticeably:

• Low inductance
  → rapid current increase
  → short, hard arc
  → higher melting performance
  → more spatter possible

• High inductance
  → slower current increase
  → softer, smoother arc
  → less spatter
  → more even weld bead

Inductance affects exclusively the timing behaviour of the current, not the maximum output of the machine.

Why is there an inductance control?

Different materials, sheet thicknesses, and welding positions require different arc behaviours.
Inductance control allows the welding process to be specifically adapted to the particular application without changing basic parameters such as current or wire feed.

Advantages of inductance adjustment

• Influencing the arc stability

• Reduction of welding spatter

• Better weld appearance

• More pleasant welding experience

• Adaptation to thin or thicker materials

Especially with thin sheets, higher inductance can help make the process more controlled and cleaner.

Typical application examples

• Thin sheet:
  Higher inductance → softer arc, less spatter, better control

• Thicker material:
  Lower inductance → more direct arc, greater penetration

• Positional welding:
  Adjusted inductance → more stable process in constrained positions

Inductance in MIG/MAG welding machines

Inductance is particularly relevant in MIG/MAG welding, as wire feed and arc interact continuously here.
Many modern machines, such as the MIG 210 SYN from RED by Lorch, regulate inductance automatically or offer the user a manual adjustment option for fine tuning.

Summary

Inductance is an important control factor for the dynamic behaviour of the arc.
It influences how smooth, soft or direct the welding process runs, and helps to reduce spatter and improve weld quality.
With the right setting, the welding process can be optimally adapted to the material, position and personal working style.

Note:
Whether and how the inductance can be set depends on the device.
You can find further information in the device-specific articles in the knowledge base or in the respective operating manual for your RED welding machine