The Workhorse 300ST


The Workhorse 300ST

The Workhorse 300ST

Arc Starter TIG Welder, Stick Welder


The Workhorse TIGweld 300ST is a very rugged capacitor discharge arc starter TIG/Stick welding machine, weighing approximately 80lbs/36.3Kgs, and designed specifically for demanding TIG welding where the tungsten (wolfram) electrode is not allowed to touch the base metal which could cause contamination of the weld. The underlying design concept was to employ proven electrical and mechanical technologies and build a “no-nonsense”, cost-effective machine where usability, reliability and ruggedness are the most important design parameters. This in combination with a capacitor discharge arc starter makes the Workhorse TIGweld 300ST a remarkable TIG machine. The single pulse starting the arc does not produce radio noise, which can interfere with cell phones and other communication systems. For this reason, the capacitor discharge TIG welder is a better solution than high frequency (HF) systems, which do cause interference.

Product Specification


  • TIG and Stick welding current from 10 – 400 Amperes in 2 ranges.
  • Available in dual primary voltage, 240V (single or three phase) and 480V. Also available in single voltage 240V, 480V, 575V and 400V.
  • Easy to strike the arc. The spark jumps half an inch in argon gas and stops when the TIG arc is established. The Workhorse 300ST even has an inside adjustable pre flow and post flow.
  • Carbon arc gouging protection. (Circuit design that eliminates the harmful currents caused during arc gouging has been added)
  • Constant-Arc-Power characteristic means less dependence on a steady hand to achieve a good weld and reduces risk for electrode “sticking”. The Constant-Arc-Power characteristic is, if possible, even more advantageous when TIG welding than when stick welding. The TIG arc remains the same cylindrical shape without flaring out when increasing the arc length. The Constant-Arc-Power characteristic makes burn-through almost impossible when increasing the arc length. This means that you can forget about holding a constant arc length, which makes TIG welding much easier.
  • Corrosion Resistance: All welders shipped after June 15, 2005 include Seahorse protection to withstand corrosion in natural environments such as those found in shipyards, power plants, offshore oil rigs and in mines. Our process is based on experiences of 1,000+ welders used on the oil rigs in the North Sea. Arcon guarantees all models against corrosion-related failures for five-years.
  • Smart surge control reduces weld puddle agitation caused by big drops from low hydrogen electrodes, eliminating a major cause of slag inclusions in the weld.
  • Inverter circuitry allows for low weight (80lbs/36Kg) and rugged design.
  • Fiberglass enclosure allows for rough handling in demanding, tough environments.
  • The case has extra thick “skids” on the bottom case as part of the design protecting the welder when dragged on almost any surface.
  • Foldable handles with built-in grooves, as well as ridges in the case, makes nesting of units easy and practical.
  • Foldable handles with built-in grooves, as well as ridges in the case, makes nesting of units easy and practical.
  • Units can be connected in parallel for higher current or in series for higher voltage, should there be a need.


The Workhorse 300ST provides exceptional ruggedness and durability in tough and demanding environments such as construction, shipbuilding, nuclear power plants, and offshore welding. The case is made out of solid fiberglass, which provides sturdier resistance to dents and forces than a sheet metal case.


The Workhorse 300ST uses an SCR inverter design for its power supply. The inverter design allows for an industrial welding machine weighing only 79lbs/36kgs. We have chosen the proven SCR component instead of the IGBT because of reliability. We have strong indications from the market that SCRs are up to 100 times more reliable in welding applications.

TIG Welding

The Arc Start feature allows no contact between material and torch. The Arc Start feature is therefore the best solution for critical TIG welding.

Smart Hot Start

Brings the puddle temperature up quickly for good initial penetration. The amount of Hot Start is dependent on the weld puddle temperature. The Workhorse 300ST measures the time in between welds. The longer the period between stopping and starting, the greater the Hot Start current. If the arc is broken for less than a second, the Hot Start is eliminated. This prevents the puddle from overheating and burning through.

Thermostat-controlled Cooling Fan

The cooling fan starts automatically when welding current exceeds 100 A. If the current drops below 100 A, the fan will stop after approximately 6 minutes. If the fan is operating when the work is discontinued, the fan will continue to run and stop after approximately six minutes.

Option – The Warhorse

The Warhorse 300ST is a 400V or 480V welder designed to protect the machine from voltage spikes and over voltage surges commonly found in environments with very “dirty” power distribution system, such as power plants and shipyards and some generators.This high resistance to surges and spikes has been achieved by vastly increasing the capacity of existing surge protection circuits, adding new surge protectors and by using high voltage rated components in critical parts of the inverter circuits.

Safety, Warranty and Service

The welding units are designed to meet UL551 and CE requirements.
The units come with a factory warranty and user manual.
Service will be taken care of by the factory or can in many cases be performed locally by your service authorized Distributor.

Product Specification


Rated Welding Current (AMPS) @ Duty Cycle
Welding Amp Range
Open Circuit Voltage
Imput Amperes at Rated Load Output 50/60 Hz
Three Phase

400A @ 29%

300A @ 60%

250A @ 100%

Range 1

20A @10V
-180A TIG

10A @20V to 180A @ 27V Stick

Range 2

80A – 400A

80 max

Height: 17.9″
(45.5 cm)

Width: 10.5″
(26.7 cm)

Depth: 19.5″
(49.5 cm)

80 lbs.
(36.3 kg.)
85 lbs.
(38.6 kg)
Single Phase
200A @ 28V

* 240V, 400V, 480V & 575V
Maximum output will be decreased when operating on 208 Volts AC.