The powerful professional units

The welding units series LogiTIG are based on inverter technology and guarantee high-performance welding characteristics combined with a high degree of flexibility.

The handy, portable systems can be used for aluminum welding in AC operation and for steel and stainless steel with direct current (DC) as well as for MMA / stick electrode welding.

Only a few control buttons on the front allow easy handling of the system. Nevertheless, a variety of functions and parameters for the demanding user are available in „expert mode“.

The product line includes three devices:

LogiTIG 221 AC/DC

LogiTIG 240 AC/DC

LogiTIG 300 AC/DC

Functionality and easy operation

  • Continuous setting of the welding current.
  • State-of-the-art Inverter technology.
  • Operation at 230 V single phase (LogiTIG 221/240 AC/DC).
  • High frequency (HF)-ignition and LiftTIG ignition.
  • 3 different AC curves selectable, square, sinusoidal and noise reduced.
  • Jobs: Saving and loading of complete parameter settings.
  • 2 welding currents that can be activated through the welding torch.
  • Digital display for welding current, time and frequency with pre-display and hold function.
  • TIG pulse mode as a standard.
  • AC balance control for the modification of the arc curve and penetration.
  • Adjustable AC frequency 50 – 200 Hz.
  • Adjustable parameters: start/end current, upslope/downslope, gas pre/post flow.
  • Temperature activated cooling fan.
  • Approved for welding in confined areas, S-symbol approved.
  • MMA/stick electrode welding.
  • Torch with potentiometer as an option.
  • Optional: Water cooling unit
  • High frequency TIG-DC-pulse up to 12 kHz for a defined narrow arc plasma alike.

Merkle High Frequency DC Pulse - Concentrated, narrow welding arc!

High frequency DC pulse

The machines of the series MobiTIG and LogiTIG come as a standard with the highfrequency DC pulse. The arc can be pulsed with a frequency up to 12 kHz. The arc characteristics provide outstanding opportunities in TIG DC welding that are not available in the normal TIG arc:

Standard TIG weld

High frequency DC pulse weld


  • Extreme arc constriction.
  • Arc similar to plasma welding.
  • Less heat input.
  • Higher welding speed.
  • Extremly stable arc.
  • Perfectly for corner welds.
  • Low noise emission.

Portable TIG Welding Machines - Welding units for DC!

The welding units MobiTIG 190 DC, MobiTIG 280 DC and TIG 300 DC are suitable for TIG welding in DC of stainless steel, mild steel and copper. All units can operate in MMA/stick electrode mode. The units can be characterized by numerous features.


  • Continuous setting of the welding current.
  • Low weight, portable.
  • 2-stroke/4-stroke operation.
  • High frequency (HF) and LiftTIG ignition.
  • Socket for remote control.
  • Digital display for all parameters, with predisplay and hold function for welding current .
  • Job programs (MobiTIG).
  • 2 welding currents with activation at the welding torch.
  • TIG pulsation as a standard.
  • Adjustable start/final current and downslope time.

Portable TIG Welding Units - Perfect in handling and functionality!

Display (series LogiTIG):

  • Digital display as a standard.
  • Expert mode or standard mode programmable.
  • Different languages selectable.
  • Lock through PIN security number.
  • Easy operation through rotary switch.

TCG torch connector:

The main advantages of the Merkle TCG (TIG Center Gas) connector:

  • Small size
  • Low weight
  • Exchange of the torch without tools
  • Negative socket for connection of TIG torch and electrode cable
  • 2 rubber rings assure gas seal achieved

MMA/stick electrode welding:

  • Arc force: Increasing of the welding current in order to avoid adherence of the electrode.
  • Hotstart function: Increasing of the start current to assure a safe ignition. The hotstart current and time are adjustable.
  • Anti Stick function: In case of adherence of the electrode, the current
    is switched off immediately. Re-ignition after separation is only possible with a short delay.

TIG Welding Units - Trolleys and water cooling units!

Trolley TW 120:

The trolley TW 120 is designed for easy transportation of the welding unit in the
workshop or on site.

  • Extra large wheels (200 mm).
  • Gas bottle holder for a 10, 20 or 50 l cylinder (if machine is fixed to the trolley).
  • Drawer for tools, accessories, spare parts and consumables.
  • Suspension possibilities for cables and torch heads.
  • Torch holders for varions welding torch types on left and right side

Water cooling units WK 200/230/300:

The water cooling units can be mounted as an option to the welding units MobiTIG 280 DC, LogiTIG and TIG 300 DC. Welding machine and water cooling unit then form one compact unit, easy to transport. Different applications are possible: welding with a water cooled torch in the workshop or using a gas cooled torch on site. Easy mounting and dismounting in a few seconds, via one pluggable electrical connection(option) placed on the rear panel of the unit.

Technical Data

Power supply

Pluggable cables to the power source
Water pump Rotatory pump
Pressure switch  Integrated
Water connection 2 quick disconnect couplings

12 kg (WK 200)
18 kg (WK 230)
20 kg (WK 300)

Dimensions L x W x H 

590 x 200 x 200 (WK 200)
610 x 230 x 215 (WK 230)
600 x 300 x 260 (WK 300)

*: Slow-blow fuse 16 A
**: Slow-blow fuse min 20 A
*** BiPower operation
Technical details are subject to change

Technical Data