Power Source

TIG | GTAW  Digital Welding Inverters

Features :

Constant Current Output Provided

The output of SigmaWeld Welding inverters are constant even if there is a power fluctuation in the mains of upto +/- 15%. The powersource works equally well with Generator Sets with balanced load.

Energy Saving , VRD Inbuilt

When the operator is not welding for more than 2 minutes, the power source automatically switches to low open circuit voltage output below 24V for safety of operator. This also leads to saving of no load losses.

Excellent Welding Performance

The optimized design along with added features like Inbuilt Hot Start and Inbuilt Arc Force Control, helps achieve seamless beads with all steels and alloy steels. The parameters settable are Peak Current, Base Current, Peak Time, Base Time, Upslope Time, DownSlope Time, Gas preflow, Gas Post flow. If the operator presses the torce switch but does not start welding, the Gas Solenoid is switched off within 10sec. ensuring no wastage of Shielding Gas. In case the tungsten touches the job, the welding current and voltage are stopped immediately, helps avoid Tungsten Inclusion defects.

Protections and Safety

SigmaWeld welding inverters are designed for Safety of both operator and machines. It has inbuilt protections for Overvoltage, Undervoltage, Output Short, Thermal Overload and IGBT Peak Current locking. This ensures longer life of equipment and our inbuilt Voltage Reduction Circuit which ensures OCV as low as 24 Volts or below when not welding keeps operators safe.

Water Cooling Unit Interlocking

SigmaWeld WCS (Water Cooling System) can be easily mounted below the SigmaWeld Welding inverters making in one completely integrated unit. The SigmaWeld WCS contains Stainless Steel Tank, Radiator and Forced Air Cooling. Interlocking of Water Cooling Unit with the program ensures that the WCS is operational only in the GTAW mode. This is to safe guard the Welding Torch and operator.

Welding Automation and Accessories

SigmaWeld GTAW machines can be controlled with the help of our standard push button based remotes, Potentiometer based remotes or Foot Controlled Remote for adjusting Welding Current during welding.

SigmaWeld GTAW machines can be interfaced with Robots, Welding SPM’s and other systems with ease.

SigmaWeld Automation Systems such as Weaving Units, AVC (Automatic Voltage Controllers), Special Purpose Machines, Cold Wire Feeders etc are specially designed to enhance productivity and quality of welding.

Product Selector Guide

Sigma Weld Model Material Thickness Ampere Range Industry Application
SW 170 0.7 to 5 mm 5 to 170 Site Work,Dairy Equipments,Pharma Piping,Training and Maintainence
SW 250 0.7 to 15 mm 5 to 250 PetroChem, Aerospace,Pharma Equipment
SW 400 0.7 to 25 mm 5 to 400 Precission Metal Fabrication,Boiler,Pressure Vessels
SW 600 1 mm upwards 5 to 600 Precission Metal Fabrication,Boiler,Pressure Vessels,Railway Wagons


Specification SW 170 PT SW 250 PT SW 400 PT SW 600 PT
Rated Input Voltage 1φ, 230V ± 10%, 50HZ 3φ, 415V ± 15%, 50HZ 3φ, 415V ± 15%, 50HZ 3φ, 415V ± 15%, 50HZ
Power (KVA) @ 100% 4.1 KVA 7 KVA 12 KVA 18 KVA
Duty Cycle @ 400C 100% @ 130 Amps 100% @ 200 Amps 100% @ 300 Amps 100% @ 400 Amps
Open Circuit Voltage 65V 60V 60V 60V
Output Range 5-170 Amps 5-250Amps 5-400Amps 5-600Amps
(D x W x H) mm 220 x 440 x 560 360 x 650 x 560 360 x 650 x 560 380 x 655 x 650
Weight 20 Kgs 40 Kgs 45 Kgs 65 Kgs

Protection, Safety Features

1) Thermal Shutdown Inbuilt(Over temperature Indication)
2) Under Voltage Inbuilt(Phase Failure Indication)
3) Over Voltage Inbuilt(Phase Failure Indication/MOV)
4) IGBT Peak Current In Built
5) VRD,Energy Saving Inbuilt
6) Cooling Type Forced Air Cooled
7) Water Cooling Interlocking Water Flow Switch(optional)
8) Output Short Inbuilt (Output Short Indication)


1) Gas Pre Flow Time Settable 0.1 S 30.0 S
2) Gas Post Flow Time Settable 0.1 S 30.0 S
3) Peak Current Time Settable 0.1 S 10.0 S
4) Base Current Time Settable 0.1 S 10.0 S
5) Welding Mode 2T 4T
6) Hot Start Current In Built 30%@ 300MS
7) Digital Ammeter & Voltmeter Inbuilt
8) Process Memory Recall Inbuilt

Models Available

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