Arcon WORKHORSE 300S User manual

WORKHORSE 300S
Stick / Lift Start TIG P/N 010300
240V, 400V, 480V, 575V, Dual Voltage 240V/480V
OPERATING MANUAL
REVISED SEPTEMBER 2009
2203 Northwood Drive, Bldg.10 Salisbury, MD 21801
Phone: [phone] Toll Free: 888.512.7266 Fax: [phone]
[email protected] www.arconweld.com

Declaration of Conformity
Manufacturer's Name: ARCON Welding Equipment, LLC
Manufacturer's Address: 2203 Northwood Drive, Building 10
Salisbury, Maryland 21801 USA
Declares that the product:
Product Name: Workhorse 300S
Model Numbers:010300-xxx, 010301-xxx, 010350-xxx
Conforms to the following standards:
Underwriters Laboratories Standard UL551
Degree of Enclosure Protection IP 24 in accordance with ISO 60529
AND
Declares that the product:
Product Name: Workhorse 300S
Model Numbers: 010300-x5x, 010301-x5x
Conforms to the following standards:
Safety: EN 60974-1 2002
This product is in conformity with the requirements of the Low-Voltage Directive
(73/23/EEC) and Machinery directive 89/392/EEC, 91/368/EEC, 93C 133/04, 93/68/EEC.
Technical Contact: Mike Bell
ARCON Welding Equipment LLC
2203 Northwood Drive, Bldg. 10
Salisbury, Maryland 21801
Fax: [phone]
Email:[email protected]
Compliance certifed by: Goran Hedberg, Design Engineer
For further details please contact the factory:
ARCON Welding LLC
2203 Northwood Drive, #10
Salisbury, Maryland 21801 USA
Tel: [phone] Toll Free: 888 512.7266 Fax: [phone]
Email: [email protected]

Part Numbering System:
010300 -001
Model Number Option 1 Option 2 Input Voltage
010300 = Workhorse 300S Stick/TIG 0 = Standard – no option 0 = Standard –no option 1 = 400V
010301 = Workhorse 300S Stick 1 = Warhorse 2 = Low Open Circuit Voltage 2 = 480V
010303 = Workhorse 300S for Mining 7 = Robot control 4 = Digital Meter (if not standard) 3 = 240V
010310 = Workhorse 300MS MIG/Stick 9 = Custom 5 = CE Approved 4 = 240V/480V
010320 = Workhorse 300ST TIG/Stick 9 = CE Approved + Digital Meter 5 = 575V
010350 = Ironhorse 300S Stick/TIG 6 = 700V DC
101001 = Studhorse 1000DM
101201 = Studhorse 1200DM

3
Workhorse 300S Operations and Service Manual
Table of Contents
CORROSION PROTECTION INFORMATION 5
GENERAL INFORMATION
User Responsibility 6
Warranty 6
Safety Standards 6
1. SAFETY
1.1 Safety Symbols 7
1.2 Safety Precautions 7
1.3 Electric Shock 8
1.4 Arc Rays and Eye Protection 8
1.5 Fumes and Oxygen Depletion 9
1.6 Welding Sparks 9
1.7 Electric and Magnetic Fields 9
1.8 Protect Yourself and Others 10
2. PRODUCT DESCRIPTION AND INFORMATION
2.1 Introduction to the Workhorse 300S 10
2.2 Product Specifications 11
2.3 Safety Standards 11
3. INSTALLATION
3.1 Handling and Unpacking the Welder 11
3.2 Selecting a Location 12
3.3 Selecting Suitable Supply Cables 12
3.4 Connecting Input Power 12
3.5 Fuses (Table 3.0) 13
3.6 Output Connections 13
3.7 Front Panel Digital Meter (Optional) 13
4. OPERATION
4.1 General Description 14
4.2 Design Features 14
4.3 Controls and Settings 14
4.3.1 Circuit Breaker (Power on/Off) 14
4.3.2 Thermostatically Controlled Cooling 14
4.3.3 Range Switch 14
4.3.4 Weld Power 14
4.3.5 Arc Force 15
4.3.6 Process Control Selector 15
4.3.7 Power On Indicator and Themal Protection 15
4.3.8 Remote Control Connector 16
4.3.9 Input Power Cord 16
4.3.10 Output Teminals 16
4.3.11 Voltage Changeover (Figure 4.3) 16
4.4 Welding Operation
4.4.1 Stick Welding 17
4.4.2 TIG Welding 17
4.4.3 Dual Voltage Changeover 17

4
5. MAINTENANCE 18
6. ELECTRICAL SPECIFICATIONS AND DIAGRAMS
6.1 General Information 19
6.2 Product Specifcations 20
6.3 Block Diagram of the Inverter 21
6.4 Main Circuit Diagrams for Various Voltages 22
6.5 Front Panel 23
6.6 Rear Panel 24
6.7Chassis Plate Drawing 1 25
6.8 Chassis Plate Drawing 2 26
6.9 Inductor Plate Drawing 27
7. PARTS & ACCESSORIES
7.1 Replacement Parts 28
7.2 Accessories 31
8.TROUBLE SHOOTING GUIDE 32

5
This machine is protected against corrosion in natural environments.
ARCON’s time-proven Seahorse manufacturing process protects electrical
components prone to failure from corrosion by design and using a compound
containing cycloaliphatic-epoxides, tetramethylen-oxide and a cationic photo-
initiator (commonly called conformal coating). This protection is incorporated
as certain electrical components and printed circuit boards are produced to
ensure excellent weathering and superior protection against humidity, moisture,
dust, fungus and other contaminants.
The Seahorse process used in this machine was developed and tested on
oilrigs in the North Sea decades ago. This protection enhances reliability,
prolongs component life and adds value to all of ARCON’s rugged line of
portable welding power sources. Listed below are some of the steps ARCON
Welding has taken to increase corrosive atmosphere resistance in this
machine:
Transformer vacuum impregnated twice and dipped an additional time.
Auxiliary transformer protected and coated to resist corrosion.
Output board encapsulated in *repair-friendly material to eliminate the failures.
Control board coated to protect against salt-water arc over.
Input board coated to protect components from corrosion.
Resistors replaced with porcelain-coated ceramic resistors.
Fan motor totally encapsulated winding coil to withstand corrosive conditions.
Terminal screws coated to prevent electrical arc-overs.
*Note: Coatings used on circuit boards are not epoxy based, thus allowing board
components to be repaired. Other manufacturers use epoxy coatings which require
expensive board replacement when components fail.
This anti-corrosion process comes with ARCON’s five-year manufacturer’s guarantee against
corrosion-related electrical failure within natural operating environments. This warranty begins
the day the machine was shipped from the factory and does not apply to equipment used in
man-made environments that produce chemical residue, dust or airborne debris of man-made
substances, etc.
Because the Seahorse protection is incorporated in the manufacturing process, any circuit
modifications, repairs or component replacement with non-ARCON parts will void the Seahorse
guarantee.
Repair centers should contact the factory to obtain replacement parts for this machine.
Customers that intend to submit a warranty request for corrosion related failure should contact
the factory to obtain a RMA number before sending the welder to the factory for evaluation.

6
GENERAL INFORMATION
USER RESPONSIBILITY
ARCON Welding warrants that The Workhorse 300S will perform in accordance with the product
description in this manual. The Factory Warranty will be null and void should the user attempt
to operate The Workhorse 300S after it has malfunctioned. Parts that are broken, missing or
worn must be replaced immediately. ARCON Welding Equipment LLC or its Authorized Repair
Center will perform warranty Repairs. The Workhorse 300S or any of its parts must not be
altered without the prior written approval of ARCON Welding Equipment LLC. Any malfunction,
which results from improper use, faulty maintenance, physical damage, unapproved repair or
alteration, shall be the sole responsibility of the user or owner.Any subsequent repair requested
to be performed by ARCON Welding Equipment LLC will be charged at ARCON’s applicable
hourly labor rate and current replacement part prices.
MANUFACTURER’S LIMITED PRODUCT WARRANTY
ARCON Welding Equipment’s only warranty is that goods being sold will be free from defects in
materials and workmanship. This express warranty is in lieu of any other warranties, either
expressed or implied, and whether statutory or otherwise, including any implied warranty of
merchantability or fitness for a particular purpose. Misapplication of equipment may void the
factory warranty. Users are encouraged to purchase the correct equipment for the job.
The Manufacturer’s written warranty for The Workhorse 300S welder has been included with
your new machine, and is limited to defect in materials or workmanship. The original purchaser
must furnish notice of defect or failure to ARCON Welding Equipment or one of Arcon’s
authorized repair centers using an approved Warranty Claim Form. Forms can be downloaded
from the company Web Site at http://www.arconweld.com. The guarantee against corrosion-
related failures can be extended to five-years by completing the Registration Form.
Any equipment that has been modified by any party other than ARCON Welding Equipment LLC,
or equipment that has been improperly installed, improperly operated, misused based upon
industry standards, improperly maintained or equipment which has been used for operation
outside of specifications will not be covered under the manufacturer’s warranty. ARCON
Welding Equipment shall in no way be liable for any consequential damages.
ARCON Welding Equipment reserves the right to make engineering and/or part changes at any
time, without notice, as improvements in quality or design are made. Owners and operators of
The Workhorse 300S should access the company Web site listed above to keep up-to-date with
offerings, applications and technical suggestions.
SAFETY STANDARDS
The Workhorse 300S is designed and built to comply with the following safety standards:
Underwriters Laboratories Standard UL551
Safety EN 60974-1
Degree of Enclosure Protection IP 24 in accordance with ISO 60529
•Protection against full penetration of solid foreign objects of 12.5mm diameter and larger.
•Protection against harmful effects from splashing water against the enclosure from any
direction. Please review all safety infomation in Section 1 very carefully before operating the
machine.

7
1. SAFETY
Safety is eveyone’s responsibility. ARCON designs every machine with safety in mind, and a
safe work environment depends largely on you. Do not install, operate, or repair this
equipment without carefully reading this manual and observing all of the safety
precautions mentioned. If there is a question, ask your supervisor!
1.1 Safety Symbols
Every effort has been made to protect trained operators from injury or unnecessary risk. Certain
symbols are used throughout this manual to call attention to safety-related information and
instruction. The safety symbols in this manual have these meanings:
This symbol indicates Dangerous Situations. When this symbol is used in this manual,
death or serious bodily harm is possible or probable if the corresponding preventative measures
are not taken. Operators must take caution in the method and manner of handling or using the
machine when this symbol is displayed.
1.2 Safety Precautions
Do not install, operate, or repair The Workhorse welding equipment without reading this
manual and all safety precautions stated within!
This machine was designed and built with operator safety in mind, but safety begins with you!
Every effort has been made to protect the trained operator from injury. Please become familiar
with the information in this manual to minimize the risk of shock or injury.
ARC WELDING CAN BE HAZARDOUS. ALWAYS PROTECT YOURSELF
AND OTHERS FROM POSSIBLE INJURY OR DEATH. KEEP CHILDREN AWAY.
OPERATORS WHO WEAR A PACEMAKER SHOULD CONSULT WITH THEIR
PHYSICIAN BEFORE OPERATING STUD WELDING EQUIPMENT.
THIS OPERATOR’S MANUAL SHOULD ALWAYS BE KEPT WITH THE MACHINE
FOR QUICK REFERENCE. ALL SAFETY WARNINGS, SIGNS AND STICKERS
MUST STAY ATTACHED TO THE MACHINE. ALL OPERATORS MUST BE
PROPERLY TRAINED AND PROTECTED BEFORE OPERATING THIS EQUIPMENT.

8
1.3 ELECTRIC SHOCK
Precautionary measures must be taken to provide maximum protection against electrical shock.
Electric shock can injure or Kill
WARNING
1. Do not touch live or energized electrical parts or store metallic objects near power.
2. Ground the work or metal to be welded to a good electrical (earth) ground.
3. Do not leave an energized machine unattended.
4. Never work in wet clothing, gloves or footwear.
5. Insulate yourself from work and ground using dry insulation. Make certain the insulation
is large enough to cover your full area of physical contact with work and ground.
6. Inspect all system components, protective equipment, cables, connectors and gas lines
prior to operating equipment. Never use cables that are longer than necessary.
7. When testing a live unit, use the one-hand method. Do not put both hands inside of the
unit. Keep one hand free.
8. Disconnect input power conductors from de-energized supply line before moving a
welding power source.
9. Always be sure the work cable makes a good electrical connection with the metal being
welded. The connection should be as close as possible to the area being welded.
10. Turn OFF welding power source before servicing unless the procedure specifically
requires an energized unit.
11. Never use the power source to provide heat for thawing frozen pipes.
1.4 ARC RAYS and EYE PROTECTION
Arc rays can injure eyes and burn skin. Arc flashes are painful.
To minimize the risk of eye injury by arc rays, always:
1. Use a shield with the proper filter and cover plates to protect your eyes from sparks and
the rays of the arc when welding or while observing open arc welding.
2. Use protective clothing specifically intended for work with welding equipment. It should
be made of durable flame-resistant material to provide ample protection from the arc
rays.
3. Protect other nearby workers with suitable, non-flammable screening. Caution other
workers not to watch the arc nor expose themselves to the arc rays or to hot spatter or
metal.

9
1.5 FUMES and OXYGEN DEPLETION
Only weld in areas or rooms where adequate ventilation of weld gases is possible, and
where there are not fire, smoke or explosion hazards.
1. When working in a confined space always have trained support personnel nearby.
Welding fumes and gases can displace air and lower the oxygen level causing injury or
death. Be sure the breathing air is safe.
3Do not weld in locations near degreasing, cleaning, or spraying operations. The heat and
rays of the arcs can react with vapors to form highly toxic and irritating gases.
4Do not weld on coated metals, such as galvanized, lead, or cadmium plated steel. The
coating must be removed from the area to be welded. Coatings and metals containing
above elements can generate toxic fumes when heated to welding temperature.
1.6 WELDING SPARKS
Heat from flames and arcs can start fires. Hot slag or sparks can also cause fires and
explosions.
1. Remove all combustible materials from the work area or cover these materials with a
protective non-flammable tarp. Combustible materials include wood, fabrics, sawdust,
liquid and gas fuels, solvents, paints and coatings, paper, etc.
2. Hot sparks or hot metal can fall through cracks or crevices in floors or wall openings and
cause a hidden smoldering fire. Make certain that such openings are protected from hot
sparks and metal.
1.7 ELECTRIC AND MAGNETIC FIELDS
Electric current flowing through any conductor causes localized Electro-Magnetic Fields
(EMF). Welding and cutting current creates EMF around welding cables and welding machines.
1. Operators having pacemakers should consult their physician before welding. EMF may
interfere with some type of pacemakers.
2. Exposure to EMF may have other health effects, which are unknown.
3. Operators should use the following procedures to minimize exposure to EMF:
a. Route the work cables together. Secure them with electrical tape when possible.
b. Never coil the work cable around any part of your body.
c. Do not place your body between the work cables. Route cables on the same side
of your body.
d. Connect the work cable to the work piece as close as possible to the area being
welded.
e. Keep welding power source and cables as far away from your body as possible.
4. Electromagnetic fields can irrevocable erase magnetic data carriers (computer memory,
credit cards, security ID cards or data storage diskettes).
5. Electromagnetic fields may magnetize and damage watches or similar digital devices.

10
1.8 PROTECT YOURSELF AND OTHERS!
Some welding, cutting, and gouging processes are noisy and require ear protection. The arc, like
the sun, emits ultraviolet (UV) and other radiation and may injure skin and eyes. Hot metal can
cause burns. Training in the proper use of welding processes and equipment is essential to
prevent accidents.
1. Always wear safety glasses with side shields in any work area. In conjunction with eye
protection, welding helmets or face shields are also required.
2. Use a face shield fitted with the correct filter cover plates to protect your eyes, face, neck,
and ears from sparks and rays of the arc when operating or observing operations. Warn
bystanders not to watch the arc and not to expose themselves to the rays of the electric
arc or hot metal.
3. Wear flameproof type gloves, heavy long-sleeve shirt, cuff less trousers, and a welding
helmet or cap for hair protection, to protect against arc rays and hot sparks or hot metal.
A flameproof apron may also be desirable as protection against radiated heat and
sparks.
4. Hot sparks or metal can lodge in rolled up sleeves, trouser cuffs, or pockets. Sleeves and
collars should be kept buttoned, and open pockets eliminated from the front of clothing.
2. PRODUCT DESCRIPTION AND INFORMATION
2.1 INTRODUCTION TO THE WORKHORSE 300S
The Stickweld 300S is a portable welder using an inverter-type power supply to generate the
output power.
The Stickweld 300S is primarily designed for stick welding (SMAW). It can also be used for TIG
(GTAW) welding, using the Lift Start principle, as well as arc gouging and stud welding. Use
Range I when stickwelding, when possible. The first range produces a softer arc than that of
Range 2.
The Workhorse Stickweld 300S is available in the following models: 240V single voltage
operating in single phase or three-phase; 480V single voltage operating in three-phase; 575V
single voltage in three-phase, 240-480V dual voltage, and 400 V single voltage operating in
three-phase. The three-phase supply voltage is connected to a circuit breaker and then to a
three-pulse rectifier cicuitry and a radio noise suppression module. The AC voltage is connected
to a step-down transformer to power the welder. The AC welding voltage is first rectified to
create a DC welding current. The control logic measures the welding voltage and welding
current. It also makes the inverter create the suitable welding characteristics. The fan control
starts and stops the cooling fan. The auxiliary transformer steps down the input voltage to 48V
centertapped. This transformer powers the cooling fan and the contol logic.

11
2.2 PRODUCT SPECIFICATIONS
Product Specifications for 300S
Rated
Welding Welding
Open Input Amperes at Physical Weight
Primary Current
(Amps) Range
Amps Circuit Voltage
Rated Load Output
50/60 Hz KVA KW Efficiency
Dimensions
Input @ Duty Cycle 240 400 480 575 Net Ship
Three
Phase
400A@29%
300A@60%
250A@100%
Range 1
30-180A
Range 2
80 Max 37
±10%
25
±10%
20
±10%
18
±10%
14.9
12.05
±20%
79.60% Height: 17.9" 45.5cm
Width: 10.5"
26.7cm
Approx.
80lbs.
36.3 kg.
Approx.
90lbs.
41.0kg.
Single 200A@100%
80A-400A 45 NA
NA NA NA NA Depth: 19.5"
Phase 28V 49.5cm
240V/480V DUAL VOLTAGE, & 240V, 400V, 480V & 575V SINGLE VOLTAGE
2.3 SAFETY STANDARDS
The Workhorse 300S product and manufacturing specifications comply with the following safety
standards:
Underwriters Laboratories Standard UL551
Safety EN 60974-1
Degree of Enclosure Protection IP 24 in accordance with ISO 60529
•Protection against full penetration of solid foreign objects of 12.5mm diameter and larger.
•Protection against harmful effects from splashing water against the enclosure from any
direction.
3. INSTALLATION
WARNING!
•Only qualified personnel should perform this installation.
•Turn the input power off at the disconnect switch or fuse box before working on
The Workhorse.
•Do not touch electrically hot parts.
This section provides detailed instructions for the proper installation of The Workhorse. It is
recommended that these instructions be followed carefully to allow for the best possible
operating environment.
3.1 Handling and Unpacking the Welder
Since the Workhorse 300S machine weighs approximately 90 pounds in the shipping carton, no
fork lift or special handling equipment is necessary to move the machine. The shipping carton
has built-in reinforced handles to enable two people to easily transport the machine.

12
Immediately upon receipt of the welder, inspect the shipping box for any damage and notify the
carrier of such damage before accepting delivery. Then inspect the Workhorse for damage,
which may have occurred in transit. After removing the components from the shipping
container(s), check the container for any loose parts. Remove all packing materials.
Check air passages of power source for any packing materials that may obstruct airflow through
the welder.
If the equipment is not being installed immediately, store it in a clean, dry, well-ventilated area
until installation.
3.2 Selecting a Location
The location of the power source should be carefully selected to ensure satisfactory and
dependable service. Choose a location relatively close to a properly fused source of electrical
power.
It is important that the machine be located in an open area where air can circulate freely through
the front and rear openings. If space is at a premium, leave at least 1 foot (300 mm) of clearance
between the rear of the power source and wall or other obstruction.
3.3 Selecting Suitable Supply Cables
The standard power input cable for the Workhorse 300S welder is a high quality #10gauge that
is 12.5 feet long. The secondary cables that connect the electrode holder or TIG torch vary in
length according to needs, but are normally 1/0 gauge and 25 feet in length. Heavier 2/0 gauge
cables can be used to extend the distance between the machine and work surface. Standard
ground cables are 1/0 gauge and 25 feet in length. Work cables and accessories may be
optionally supplied with the Workhorse 300S power.
WARNING!
•Only qualified personnel should perform this installation.
•Turn the input power off at the disconnect switch or fuse box before working on
The Workhorse machine.
•Do not touch electrically hot parts.
3.4 CONNECTING INPUT POWER
The primary cable supplied with the power source has 4 conductors, with the exception
of the 575V machine, see note below. When connecting an attachment plug or hard
wiring to an electrical service box, connect the green wire to the ground. The remaining
3 conductors can be connected to the phases in any order.
Note: 575V welders have 5-conductor primary cable with two ground
wires, green and orange.
For single phase 240V connection, the RED lead is not connected.
Once connected to the primary power, the power source must be turned OFF before the
unit is moved.

13
3.5 FUSES
It is recommended that input fuse sizes be in accordance with the table below:
Input Voltage Welder input
Maximum Amperage Recommended Fuse Capacity
240 V Three-Phase 37 35
240 V Single-phase 45 50
400 V 25 25
480 V 20 25
575 V 18 25
Table 3.0
3.6 OUTPUT CONNECTIONS
The standard supplied output connector types are female Dinse type (manufactured by
DIX). Special order welders may have been supplied with optional connector types
(Tweco or Cam-Lok) if special ordered.
There are several manufacturers of electrode holders, TIG torches (either air or water
cooled) and ground clamps. They are often current and use specific, and customers
should use care in determining the accessories that they will require. Always consult the
manuals or instructions provided with these accessories to ensure safe use and that the
connections are properly made.
3.7 Front Panel Mounted Digital Meter (optional)
The Digital Meter provides real-time Voltage and Current (switchable) output readings.
The front panel meter can be switched into two modes by pressing the black mode button:
1. Output Voltage of the welder in real-time.
2. Output Current of the welder.
During welding, the meter shows the current that is being delivered.
When welding stops, the meter will show the last Current that was delivered for a
period of 3 seconds, and then revert back to real time.

14
4. OPERATION
WARNING!
PLEASE READ CHAPTER 1REGARDING SAFETY
4.1 General Description
The Workhorse power source combines time-proven technology with modern technology to
provide high-quality performance. The digitally controlled SCR type inverter is very reliable in
welding applications and able to deliver up to 400 Amps@29% Duty Cycle.
4.2 Design Features
The Workhorse power source is designed to be portable and easily transported to provide many
benefits. No special lifting devices are required to move or maintain the machine. The machine
provides Constant Power output with Inverter-smooth arc, incorporating digitally-controlled
start/stop with no mechanical contactor. Other features include regulated output, step-less weld
power and time adjustment, short-circuit protection, automatic line voltage protection and 5-
zones of thermal protection. The sound the machine generates is somewhat different from the
sound of other inverter and non-inverter machines due to the Workhorses unique SCR type
inverter frequency. Operators should rest assured that the sound is normal and not a defect.
4.3 Controls and Settings
4.3.1 Circuit Breaker (Power On/Off)
The Circuit Breaker is located on the control panel at the rear of the machine. Move
the switch lever up to the ON position to start the machine. This also activates the
Thermostat-controlled Cooling Fan for approximately 6 minutes indicating that
correct power connections have been made.
4.3.2 Circuit/Time-controlled Cooling Fan
The cooling fan starts automatically when welding current exceeds 100 A. If the
current drops below 100 Amps, 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.
4.3.3 Weld Current Range Selector
Two different settings (10 -180 Amps and 80 -400 Amps) are available. Each
setting defines a specific range of output current for the welder. Do not change
ranges while the machine is in use.
4.3.4 Welding Power Control
This continuous control is used to adjust the welding current from minimum to
maximum value, depending on the setting of the Weld Current Range Selector.

15
4.3.5 Arc Force Control
This control is used to adjust the Arc Force on constant current applications. The
control is fully adjustable from 0 to 100%, with 0 being very soft and 100% being
very hard. When adjusting the Arc Force, the low settings will produce a soft arc
and the high settings will produce a more forceful or driving arc. Please note that
the higher settings will produce higher levels of spatter.
The higher setting will create a more stable arc for electrodes that easily become
unstable, such as cellulose (5P).
If you do not know the optimal setting for the electrode you are using, start at the highest
setting and lower it until the arc just begins to become unstable.
4.3.6 Process Control Selector
The Process control selector has three settings, Stick, TIG and Stick. The
Standard 300S has the same characteristics for both Stick settings. The pipe-
welding version has a cellulose characteristic, allowing 1 inch of arc length when
this method of whipping is used.
The TIG position allows Lift Start, which allows contact between material and
electrode without damage to the electrode.
4.3.7 Power-On Indicator
Indicates power on/off. The power indicator will blink if any component is
overheated. Allow the welder to cool down. This may take 3 minutes or more
depending on which component is overheated. The following components are
temperature monitored:
•Main Transformer
If a 30% duty cycle is exceeded when drawing 400A output current, the Main
Transformer could overheat and shut down the welder. If overheating occurs, wait
1 minute before restarting. This condition can also occur if a 60% duty cycle is
exceeded when at 300Amps output.
•Main Inductor
If welding at 250 Amps for more than 30 minutes without stopping, the Main
Inductor will overheat and shut down the welder. If this occurs, wait 7-8 minutes
before restarting.
•Output Capacitor
When welding at the lower current settings in Range 2, or when arc gouging for
long periods, the Output Capacitor may overheat and shut down the welder. If this
occurs, wait 10 minutes before restarting. The temperature sensor will protect the
output capacitor.
•Input Capacitor:
Should one phase be lost when welding with three-phase input power, current to
the Input Capacitor could increase causing it to potentially overheat or be
destroyed. Wait 10 minutes before restarting the welder.
•Fan Motor: Some operation with restricted airflow will overheat the fan motor.
Wait 10 minutes before restarting the welder.

16
4.3.8 Remote Control Connector
Two different types of remote control connectors are available. Units come
standard with a 14-pin panel mounted female socket plastic shell connector. Some
units may be delivered with a 14-pin female socket metal shell connector. The
remote control function is automatically activated when a pin compatible remote
control is plugged into the connector.
4.3.9 Input Power Cord
The standard factory installed input power cable measures 12.5 feet. A longer
power cable length may optionally be ordered.
4.3.10 Output Terminals
Select output cable size based on Table 4 below
Duty cycle(%) Current (A) Length (Ft) Cable Size (AWG)
30 180 1 -50 2
60 300 1 -150 1/0
60 300 150 -200 2/0
4.3.11 Voltage Change Over
The Voltage Change Over opening is located on the rear panel, to the right of the
input power cable. Voltage change over is easily facilitated by inserting a flat
blade screwdriver into the opening and rotating a quarter turn. In the Low Voltage
(240V) setting the blade is horizontal and for the High Voltage (480V) setting the
blade is vertical. Please use care. The switch only rotates between two points.
See 4.4.3 Dual Voltage Changeover for additional instruction
FIGURE 4.3
RANGE SWITCH
4.3.3
POWER ON
INDICATOR
4.3.1
PROCESS SWI
TCH
STICK
”LIFT START” TIG
4.3.6
WELD POWER
4.3.4
ARC FORCE
4.3.5
CIRCUIT BREAKER
(POWER ON/OFF)
4.3.1
OUTPUT TERMINALS
4.3.10
REMOTE CONTROL
CONNECTOR
4.3.8
INPUT POWER
CORD
12.5 FT (3.81m) LONG
4.3.9
THERMOSTAT
CONTROLLED
VENTILATION
4.3.2
VOLTAGE
CHANGE OVER
4.3.11

17
4.4 Welding Operation
4.4.1 Stick Welding
1. All secondary outputs must be connected to output terminals of the power source
2. After the primary input connections have been made, close the main wall disconnect
switch or circuit breaker.
3. Place the primary power selector in the ON position. This will turn on the control circuitry.
The Power-On light on the front panel will be lit.
4. Place the Mode Selector in the ‘Stick’ position. The welding output will be energized and
the electrode holder will become “electrically-hot”.
5. Place the Arc Force Control Selector in its mid position.
6. Adjust the Weld Power Control to fit the type and diameter of electrode to be used, as
recommended by the electrode manufacturer.
4.4.2 TIG Welding
The TIG position allows Lift Start, which allows contact between material and electrode with
no damage to the electrode.
1. When the tungsten (wolfram) electrode touches the work piece, 10 Amps of current will
flow. When the electrode is lifted a small distance from the work surface the full welding
current (as set on the Welding Power Control knob) will flow.
2. When the selector is at the TIG position, the open circuit (no-load) voltage is reduced
from 78 V to 9 V. This feature prevents the tungsten electrode from sticking to the work
piece.
4.4.3 Dual Voltage Changeover
Prior to changing voltage, the unit MUST BE TURNED OFF FOR AT LEAST 2 MINUTES.
This will give time for the capacitors to discharge. The welder is equipped with a protection
device to prevent an overvoltage condition. If the unit is configured for 240V (horizontal slot)
and connected to a 480V supply, the circuit breaker switch will trip, disconnecting the
overvoltage.
DO NOT ALLOW THIS CONDITION TO BE REPEATED MORE THAN 10 TIMES.
Warranty will be voided if the unit is exposed to excessive overvoltage trip sequence.
The dual voltage (240/480V) Workhorse machine is equipped with a very durable designed
circuitry. A switch similar to the reliable range switch is used to change between the two
voltages, 240V and 480V. The switch changes the power capacitors, the main transformer
and the auxiliary transformer by turning the switch shaft 90 degrees. The opening exposing
the switch shaft is located at the rear panel to the right of the primary cable. See Fig. 4.1
How to change voltage
Please follow the instructions on the Volt Changing Label, copy below:
DISCONNECT the machine by moving the circuit breaker off (downwards).
WAIT one minute.
Disconnect the power from the panel or pull the power plug.
Place a flat blade screwdriver into the opening and locate the slot in the shaft. The
welders are set for 480V at the factory and the blade will fit into the slot vertically.
For 240V, turn the screwdriver 90 degrees (1/4 turn) counter-clockwise. For 480V
turn blade 90 degrees (1/4 turn) clockwise, i.e. horizontal slot is for 240V, vertical
slot is for 480V.

18
5. MAINTENANCE
WARNING!
Please see Chapter 1 regarding Safety
•Turn the input power OFF before working on any ARCON welder.
•Do not touch electrically live parts or electrode with your skin or wet clothing.
•Insulate yourself from work and ground.
•Always wear dry insulating gloves.
•Have an electrician install the ARCON welder.
•All maintenance and repairs that require taking off the cover must be performed by a certified
repair facility.
If The Workhorse does not operate properly, stop work immediately and investigate the cause of
the malfunction.
Please note: Opening up the case voids the Warranty. Maintenance or repair should only be
performed by an authorized ARCON Service Center, or by the factory. Do not permit untrained
persons to inspect, clean, or repair The Workhorse.Please call the factory for the location of the
Authorized ARCON Service center nearest you.
Since there are no moving parts (other than the fan) in the power source, basic preventive
maintenance consists mainly of keeping the interior of the cabinet clean. Periodically, you should
ask your Authorized Service Center to remove the cover from the case, and wearing protective
goggles, remove accumulated dust and dirt from the air passages and the interior components,
using clean low-pressure air. It is imperative that the air passages to the interior of the unit be
free of dirt to ensure adequate circulation of cooling air, especially over the rectifier bridge plates.
The frequency of cleaning will depend on the location of the unit, the amount of dust in the
atmosphere and number of operating hours.

19
6. ELECTRICAL SPECIFICATIONS & DIAGRAMS
6.1 General Information
Circuit breaker
The 3 phase elecric input power is connected to the circuit breaker (K). When the welder is used
for 240 V single phase, the brown conductor is not connected. If the correct phases are
connected the fan will start and run for a few minutes and then stop. The fan will start every time
the circuit breaker is operated.
CF Assembly
The CF assembly has three functions: as a six-pulse rectifier, as supression of electro-
magnetic interference (EMI) and as supression of voltage surges entering the welding machine
from the power lines.
Rectifier
The input rectifier consists of the power diodes CR1 to CR6.
MOVs (Metal Oxide Varistors)
If the machine is subject to a voltage surge between phases, the diodes are protected by MOVs.
MOVs are used from phases to ground (RV1, RV3 and RV6) and also between phases (RV2,
RV4 and RV5. The phase to ground MOV protects the diode from a voltage surge between
phase and ground. MOVs RV1 to RV6 protect the machine from high voltage surges. MOV
RV7 is capable of withstanding surges of up to 40 000 Amps through the MOV.
EMI (Electro Magnetic Interference)
The Electro Magnetic Interference from the inverter is supressed by two capacitors in paralell
between phase and neutral. These capacitors (C 2,3,5,6, 7 and 8) must be of type X to be
allowed to be connected between phases and also to comply with the European community CE
norms.
The type X capacitors are connected to a common point, making it a virtual neutral. This point is
connected to safety ground via two type Y capacitors and one 33-ohm resistor.
The capacitors must be of a very reliable ( HiRel ) version, type Y, as a malfunction might make
a welding machine in a steel case carry 480 V AC and therefore
could be life threatening to the operator. The 480 V version of The Workhorse must have two
Y capacitors in series to comply with the CE norms and be allowed to be sold to the European
Community (EC).
The T1 auxiliary transformer is connected to two of the 3 phases. It is protected by an internal
thermal switch (t). The surge resistors (R1 and R2) limits the current through the SCRs, should
they fire at the same time. The circuit breaker limits the time the current is flowing through thr
restors. Together they protect the SCR from destuctive current should a cross firing of the SCRs
ocurrs.
Case (Housing)
Even though the case of the The Workhorse is made of non-conductive glassfiber-reinforced
Polyester, it is designed to meet and exceed all specifications and industry requirements.