The Kemppi MasterTig 4000 MLS is an inverter power source for TIG DC welding and for covered electrodes. In TIG you set the current from 5 to 400 A, in MMA from 10 to 350 A, at a 30% duty cycle the machine holds 400 A, and in continuous work 270 A. The source alone weighs 23 kg, and a Mastercool 10 liquid cooler on the original trolley completes the bay.
What this machine is for
The power block runs on IGBT transistors with a switching frequency of about 20 kHz, so the source answers changes in the arc without delay and holds constant parameters despite load swings in the workshop mains. The range from 5 A handles thin walls, and 400 A lets you fuse deep already in the first root run, without excessive bevelling of the edge. TIG with direct current gives welds of high chemical resistance, valued on pharmaceutical and food lines, and the MMA mode up to 350 A handles thick walled industrial installations. At 23 kg the source alone is carried by one person, which at such a load capacity is rare and follows directly from the inverter construction.
The MTL panel is simple and predictable. You set the pre flow and post flow time of the gas, which closes the way to oxidation at the start and at the end of the pool, and the times of current rise and fall, which close the cycle in four stroke mode. You strike the arc without contact with an HF spark gap or by contact in LIFT mode. HF protects the electrode against sticking and against a tungsten inclusion in the weld, which matters on joints going for radiographic and ultrasonic testing. LIFT is left for places where the electromagnetic field of HF would disturb medical apparatus or numerical machines. The panel does not generate a pulsing current, so very thin acid resistant sheet you weld without a pulse, in exchange the operation is simple enough to bring a new welder in without hours of training on the interface.
The maker pointed this model to the chemical and shipbuilding industry, to pipe installations and production of tanks. The applications listed are complicated pipe welds in petrochemistry, pressure tanks of large capacity, thick walled installations welded with an electrode, repairs and assembly in district heating at the customer, joints with strict requirements of RT and UT testing in shipyards and process lines in stainless steel in the food sector. The common denominator of these jobs is joints that somebody checks afterwards, which is why a repeatable arc start and a constant current characteristic count, not the number of modes on the panel.
Features and equipment
- Power block on IGBT transistors with a switching frequency of about 20 kHz: a fast dynamic answer and a stable direct current up to 400 A.
- TIG current range from 5 A at 10 V to 400 A at 26 V and MMA from 10 A at 20.5 V to 350 A at 34 V: the full characteristic of both processes.
- Duty cycle 400 A at 30% and 270 A at 100% in TIG: a high current for work without breaks.
- Rated TIG power at 100% at the level of 13.8 kVA: data for sizing the connection.
- Open circuit voltage 80 V direct current: a sure arc start also after a longer break.
- Isolated ICS cooling layout: the air flows from the back to the front and goes around the control boards, so grinding dust and damp do not settle on the electronics.
- Mastercool 10 liquid cooler of 1 kW with a 3 litre tank: a closed circuit cools the head of the TIG torch and protects the tungsten and the ceramic nozzle in work at currents from 300 to 400 A.
- MTL panel: adjustment of the pre flow and post flow gas time and of the current rise and fall, 2T and 4T modes, HF handling.
- HF ignition: a contact free start without tungsten inclusions, the standard on work checked by radiography.
- LIFT ignition: a start by contact and lifting of the electrode, for places sensitive to electromagnetic interference.
- Arc Force in MMA mode: when a drop tries to short, the circuit adds current, which gives soft leading of the electrode in the vertical and overhead position.
- Programmable Hot Start in MMA: it makes striking basic and cellulosic electrodes easier and takes away cold laps at the start of a bead.
- Original transport trolley: the source and the cooler travel together as one bay, ready to be moved around the shop.
- Source weight 23 kg: the power unit is carried by one person, which makes work at the customer and at height easier.
- Welding of carbon, alloy and acid resistant steels, copper and titanium: the full range of materials available for direct current.
- 2T and 4T modes on the panel: four stroke takes the need to hold the trigger off the hand on long pipe runs.
Technical data
| Brand | Kemppi |
|---|---|
| Model | MasterTig 4000 MLS |
| Mains supply | 400 V, 3 phases, from minus 15 to plus 20 percent |
| TIG DC current range | from 5 A at 10 V to 400 A at 26 V |
| MMA current range | from 10 A at 20.5 V to 350 A at 34 V |
| Duty cycle 30% in TIG | 400 A |
| Duty cycle 100% in TIG | 270 A |
| Rated TIG power at 100% | 13.8 kVA |
| Open circuit voltage | 80 V direct current |
| Weight of the source | 23 kg |
| Torch cooling | liquid, Mastercool 10 cooler of 1 kW |
What you get
- Kemppi MasterTig 4000 MLS power source
- Mastercool 10 liquid cooler
- original transport trolley
What to watch out for
The supply is 400 V in three phases with a tolerance from minus 15 to plus 20 percent. This is a direct current source, so aluminium is out: for aluminium alloys a machine with alternating current is needed. The MTL panel does not generate a pulsing current, unlike the MTX, MTM and MTZ panels from the same series, which is why very thin acid resistant sheet you weld without a pulse. The duty cycle is 400 A at 30% and 270 A at 100%, and the rated power in continuous work is 13.8 kVA.
The Mastercool 10 cooler needs the fluid level checked and a fluid meant for welding systems, because plain water causes electrolysis inside the circuit. The ICS layout works properly only with a free inlet at the back and an outlet at the front of the housing, so do not put the machine against a wall and do not block the grilles. Densely packed electronics do not take conductive dust, in a dusty shop count on blowing it out from time to time. LIFT ignition takes practice, because a mistake when you lift the electrode crumbles the sharpened tip. The cooler works together with the source on the trolley, so when you plan the bay count the room for the whole set, not for the power unit alone.
This unit is sold
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