The Workhorse 300MS

The Workhorse 300MS 
CC/CV MIG/Stick Welder, 30-400A

 True to its name, the portable Workhorse MIGweld 300MS is a very rugged multi-process MIG/Stick welding machine, weighing approximately 80lbs/36.3Kgs, and designed specifically for the industrial market. 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. 

The electric circuitry is based on principles that over the years have proven their functionality and reliability in the over 100,000 welding machines sold and used around the world. 

The fiberglass reinforced plastic case also provides unique benefits over the sheet metal and thermoplastic cases used in most competing products. 

The Workhorse 300MS
Product Specification


  • MIG/Stick welding current from 30 - 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

  • 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 MIGweld 300MS can be used for MIG short arc with puddle control and spray transfer, Stick and carbon arc gouging.

  • The MIGweld 300MS uses all types of electrodes, including 6010-5P

  • The MIGweld 300MS is equipped with arc force control for stick welding

  • 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.

  • 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.

  • Inverter circuitry allows for low weight (80lbs/36.3Kg) and rugged design.

  • Fiberglass enclosure allows for rough handling in demanding environments like construction sites, shipyards and offshore oil rigs.

  • The case has extra thick “skids” on the bottom case as part of the design allowing for the welder to be easily 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.

  • Units can be connected in parallel for higher current or in series for higher voltage, should there be a need for that.



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


The Workhorse uses an SCR inverter design for its power supply. The inverter design allows for an industrial welding machine weighing only 80lbs/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.

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 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.

Arc Force
This allows the operator to adjust the current surge which results when a drop shorts the arc.

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 300MS 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 coal mines, power plants, steel mills 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. All 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 Specifications:

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
30A - 180A

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 @100%
*240V/480V Dual Voltage, & 240V, 400V, 480V & 575V SINGLE VOLTAGE

Maximum output will be decreased when operating on 208 Volts AC


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