The Lincoln Electric Invertec STT is an inverter power source for welding root runs with the STT process. You set the current from 20 to 225 A at a voltage from 20 to 29 V; at a 60% duty cycle the machine gives 225 A, and it runs 200 A without a break. Cooling is by liquid.
What this machine is for
This is a power source for the root run, that is the first layer of the weld, which decides the penetration and the tightness of the joint. The STT process, that is Surface Tension Transfer, is based on control of the current waveform in Waveform Control Technology, so you control the fusion and the heat input better than with a plain short arc.
The pulse reaches from 5 to 450 A and you set the background current from 5 to 125 A. This split limits burn through and keeps the right fusion. You weld joints with full penetration, bridge gaps and run thin materials without burning through, and there is less spatter and fume. In some applications this process replaces TIG at a higher welding speed. You work with argon based mixtures, also with helium, and with carbon dioxide on thicker wire.
Features and equipment
- The STT process, that is Surface Tension Transfer, with control of droplet transfer.
- Current waveform control, Waveform Control Technology.
- Pulse adjustment from 5 to 450 A and background current from 5 to 125 A.
- Welding voltage from 20 to 29 V.
- Work on argon mixtures and on 100% carbon dioxide.
- Liquid cooling.
Technical data
| Brand | Lincoln Electric |
|---|---|
| Type | power source for the STT process |
| Current range | 20 to 225 A |
| Voltage range | 20 to 29 V |
| Duty cycle | 225 A at 60%, 200 A at 100% |
| Pulse | 5 to 450 A |
| Background current | 5 to 125 A |
| Cooling | liquid |
What to watch out for
The record does not give the supply voltage, so settle it before you connect the machine. Cooling is by liquid, so check the fluid level and the flow before you start. The 200 A in continuous work limits the material thickness; for heavy structures you need a stronger power source.
This is a machine for root runs: you usually lay the filling passes and the cap with a second power source. The record does not list a wire feeder, a torch or an earth cable, so confirm the equipment before you buy.
How we sell used machines
This unit was checked in our service workshop in Krotoszyn with measurements to PN-EN 60974-4 and a load test. The price includes the first year of the basic service package: an inspection with cleaning of the machine and a validation measurement. Further years can be added. We ship across the European Union, collection in person by appointment.
