Ross RXT250EX User manual

Protect yourself and others by observing all safety information, warnings, and cautions. Failure to
comply with instructions could result in personal injury and/or damage to product or property.
Please retain instructions for future reference!
250AMP
MIG /MMA
INVERTER WELDER
ROSSWELDING RXT250EX

CAUTION!
THIS is a Caution symbol. This symbol is used throughout the user guide whenever there is a risk of
damaging your product. Ensure that these warnings are read and understood at all times.
IMPORTANT
PLEASE read all of the safety and operating instructions carefully before using this product. Please
pay particular attention to all sections of this manual that carry warning symbols and notices.
WARNING!
THIS is a Warning symbol. This symbol is used throughout the manual whenever there is a risk of per-
sonal injury. Ensure that these warnings are read and understood at all times.
GENERAL DESCRIPTION
A general purpose MIG /MMA welder for general purpose workshop use. The power source is an
IGBT inverter.
PRODUCT SPECIFICATION
Item RXT250EX
Input Power 230V
Frequency 50Hz
Phase No.  1
Rated No-load Voltage 53V , < 15 DC (VRD mode)
Maximum Input Current 46 Amp
Rated Input Current 27.2 Amp
MIG
Rated Output 250 Amp
Rated Duty Cycle 35%
Output Range 30-250 Amp
MMA (STICK)
Rated output 225 Amp
Rated Duty Cycle 35%
Output Range 20-225 Amp
VRD Yes

The user of this welder is responsible for his own and the safety of others. It is most important to
read, learn and respect the rules in this user guide.
When using this welder, basic safety precautions, including the following, should be followed
to reduce the risk of re, electric shock and personal injury. Make sure that you have read all of
these instructions before using this welder. Keep this booklet in a safe place for future reference.
Persons who are not familiar with this booklet should not use the welder.
WARNING! SAFETY INSTRUCTIONS
TRAINING
The operator should be properly trained to use the welding machine safely and should be in-
formed about the risks relating to arc welding procedures. This manual does not attempt to cover
welding technique. Training should be sought from qualied/experienced personnel on this as-
pect especially for any welds requiring high integrity for safety.
SERIOUS FIRE RISK
The welding process produces sparks, droplets of fused metal, metal projectiles and fumes. This
constitutes a serious re risk. Make sure that the area around the work piece is clear of all inam-
mable materials. It is advisable to have a re extinguisher to hand.
WORK AREA
Ensure a clear work area with unrestricted movement for the operator. Always maintain easy ac-
cess to the On/Off switch and the mains supply.
THE WORK PIECE
The work piece will remain at a high temperature for a relatively long period. Do not touch the
weld or the work piece unless you are wearing welding gloves. Always use pliers or tongs. Never
touch the welded material with bare hands until it has been allowed to cool.
WELDING SURFACES
Do not weld on containers or pipes that hold, or have held, ammable liquids or combustible
gases.
Do not weld coated, painted or varnished surfaces as the coatings may ignite and or can give off
dangerous fumes.
VENTILATE THE WORK AREA
Arc welding (especially using uxed core wire) emits fumes which can be dangerous. Make sure
that the work area is well ventilated.
AVOID ELECTRICAL CONTACT
Use adequate electrical insulation with regard to the electrode, the work piece and any accessi-
ble) earthed metal parts in the vicinity. Avoid direct contact with the welding circuit. The no load
voltage between the earth clamp and the torch can be dangerous under certain circumstances.
FOR ADDITIONAL PROTECTION FROM ELECTRIC SHOCK
It is recommended that this tool be used in conjunction with a residual current device (RCD)
with a rated residual current of 30mA or less.
CONSIDER WORK AREA ENVIRONMENT
Do not expose the welder to rain. Do not use it in damp, or wet locations. Keep the work area
well lit.

SAFETY INSTRUCTIONS … cont
DRESS PROPERLY
Use protective gloves and re resistant protective clothing when using the welder. Avoid exposing
skin to the ultraviolet rays produced by the arc.
ALWAYS USE THE WELDING MASK
Under no circumstances should the welder be operated unless the welding mask is protecting
the eyes and face. There is a serious risk of eye damage if the mask is not used. The sparks and
metal projectiles can cause serious damage to the eyes and face. The light radiation produced
by the arc can cause damage to eyesight and burns on the skin. Never remove the welding mask
whilst welding. Move the torch away from the work piece and release the trigger switch before
removing the welding mask.
SAFETY GLASSES
After welding use safety glasses when brushing, chipping grinding the slag from the weld.
OTHER PERSONS
Ensure that other persons are screened from the welding arc and are at least 15 metres away
from the work piece. Always ensure that the welding arc is screened from onlookers, or people
just passing by. Use screens if necessary, or non reecting curtains.
KEEP CHILDREN AND ANIMALS AWAY
Do not let children or animals have access to the welding equipment or to the work area.
SWITCHING OFF
When you have nished welding switch off the welder. Do not put the torch down with the welder
switch On and with the wire tted. When leaving the welder unattended, move the On/Off switch
to the Off position and disconnect the welder from the mains supply. Do not leave hot material
unattended after welding.
WELDING CABLES
Keep the welding cables, earth clamp and torch in good condition. Failure to can result in poor
welding quality and could be dangerous in structural situations.
CHECK DAMAGED PARTS
Before further use of the welder, any part that is damaged should be carefully checked to deter-
mine that it will operate properly and perform its intended function. Check for breakage of parts
and any other conditions that may affect its operation. Any part that is damaged should be prop-
erly repaired, or replaced, by an authorised service centre.
IMPROPER USE
Do not use this welder for pipe thawing.
HANDLING
Ensure the handle is correctly tted and always use safe lifting practices when lifting.
CAUTION! - VENTILATE THE WELDER
THERE must always be a sufcient air passage around the welder to allow for the cooling
of the transformer. If the cooling process is obstructed the welder will overheat and the overload
cut out protector will activate and cut off the welding current. If the overload cut out protector activates leave
the welder for at least 15 minutes to cool down before further use.

ADDITIONAL PRECAUTIONS
WELDING OPERATIONS:
In environments with increased risk of electric shock;
In conned spaces; In the presence of ammable or explosive materials;
MUST BE evaluated in advance by an “expert supervisor” and must always be carried
out in the presence of other people trained to intervene in emergencies.
POSITION and HANDLING
Position the welding machine on a horizontal surface that is able to support the weight:
otherwise (e.g. inclined or uneven oors etc.) there is danger of overturning.
The welder MUST NOT be supported by the operator (e.g using belts).
The operator MUST NOT BE ALLOWED to weld in raised positions unless safety plat-
forms are used.
VOLTAGE BETWEEN ELECTRODE HOLDERS OR TORCHES:
Working with more than one welding machine on a single piece or on pieces that are
connected may generate a dangerous accumulation of no-load voltage between two
different electrode holders or torches, the value of which may reach double the allowed
limit.
IMPROPER USE:
It is hazardous to use the welding machine for any work other than that for which it was
designed. Example do not use this welder for pipe thawing. The safety guards and
moving parts of the covering of the welding machine and of the wire feeder should be in
their proper positions before connecting the welding machine to the power supply.
WARNING!
Any manual operation carried out on the moving parts of the wire feeder, for example:
Replacing rollers and/or the wire guide; Inserting wire in the rollers; Loading the wire reel;
Cleaning the rollers and the area underneath them.
Should be carried out with the welding machine switched off and disconnected from the
power supply outlet . Never lift the welding machine when connected to the mains
supply.

WARNING!
When using this welder, provide adequate ventilation or facilities for the removal of weld-
ing fumes near the arc; a systematic approach is needed in evaluating the exposure
limits for the welding fumes, which will depend on their composition, concentration and
the length of the exposure itself. Do not operate on materials cleaned with chlorinated
solvents or near such substances. Remove all ammable materials (e.g. wood, paper,
rags etc.) from the working area.
WARNING!
Do not weld on containers or piping that contains or has contained ammable liquids or
gaseous products. Do not weld on containers under pressure.
WARNING!
This welding machine complies with the requirements of the technical standard for the
product for use only and exclusively in industrial environments and for professional
purposes. It is not guaranteed to meet electromagnetic compatibility requirements in the
home.
WARNING!
When using this welder, always use a welding helmet . Use special re resistant pro-
tective clothing and do not allow the skin to be exposed to the ultra violet and infrared
rays produced by the arc; other people in the vicinity of the arc should be protected by
shields of non-reecting curtains.
WARNING! Do not use in rain or store in locations affected by rain.
WARNING SYMBOLS
The following warning symbols are to remind you of the safety precautions you should take when
using the welder.
WARNING!
Read this User Guide carefully before using the welder and keep it in a safe
place for future reference.
WARNING!
When using this welder, avoid direct contact with the welding circuit. The no-
load voltage supplied by the welding machine can be dangerous in certain
circumstances.

THE RATING PLATE
The rating plate is tted to the welder and displays the following symbols and information.
Mains supply, single phase
A.C. 50/60Hz
Regulatory compliance mark.
Welding Modes
MIG/MMA
Single phase input, frequency
conversion, rectier
X Duty Cycle I2 Welding Current
I1max Maximum Input current U2 Welding Voltage
I1eff Rated input current U0 Open circuit output voltage
U1 Rated input voltage IP21S Protection class

KNOW YOUR WELDER
1
234
5
6
7
8
9
10
14
15
16
17 18
19
20
21
22
23
24
25
11
12
13
REAR PANEL
Wire feed side

[1] Mode switch MIG /MMA
[2] GREEN Power lamp
[3] ORANGE Alarm/ Temperature lamp
[4] GREEN VRD indicator (MMA mode)
[5] 2 STEP / 4 STEP selector switch (MIG
MODE)
[6] Manual Wire feed. (MIG MODE)
[7] Welding power (MIG MODE)
[8] Wire feed speed control (MIG MODE)
[9] Negative output terminal.
[10] Tool Draw
11 Euro torch connector
12 Positive output terminal
[13] Welding current control (MMA MODE)
[14] Mains input
[15] Power switch
[16] Gas input.
[17] ARC Characteristics
[18] Burn Back control
[19] Positive output terminal
[20] MIG welding polarity selection cable.
[21] Tension screw
[22] Wire feed roller
[23] Guide tube
[24] Reel Holder
[25] Negative output terminal.
LOADING THE WIRE
• SelectMIGmodewiththemodeswitchonthefrontpanel.
• Setthe2 STEP / 4 STEP selector switch [5] to 2 Touch
• Fitthetorchtotheeurotting[11]andrmlytighten.
• Openthesidecoveroftheunit
• Removetheknobfromthewirereelholder[24]andtthewirespoolontothewirereelsothatthewirewill
exitthespoolfromthebottom
• Rettheknob[24].
• Release the tension screw [21] and open the upper roller arm.
• Without letting the wire un-spool, cut the end of the wire of cleanly leaving no kinks the feed
about 30cm of the wire through the guide tube and into the wire liner by hand.
• Thewirefeedroller[22]hastwodifferentsizegroves.Checkthatthewireisalignedwiththecorrectsize
groveinthewirefeedrollerforthetypeofwireandthencarefulclosetheupperrollerandtensionscrew.If
necessaryremovethewirefeedrollerandturnitovertoaccesstheothergroveandret.
At the end of the torch
• Twistthenozzleclockwiseandpulltoremove.
• Unscrew the contact tip counterclockwise and remove. Check that the correct tip size is being
used for the wire being tted.
• Lay the torch sheath out in a straight line so that the wire move through it easily
WARNING! The following steps require applying power to the welder. Do not touch anything with the
torch or wire as it may result in accidental arcing.
• Plugthepowercord[14]intoitselectricaloutlet,setthewirefeedspeedcontrol[8]midwayandturnthe
welderON[15].
• Pressthewirefeedbutton[6]orliftthetorchhandleandcontinuepressingthetrigger
untilthewirefeedsthroughtheendofthetorchabout50mm
Note:Ifthewiredoesnotfeedthrough,viewthewirefeedunitandseeifthewireisbeingpushed.Ifitis
not,turnthewelderOFFandaddmoretensiontothewirefeedadjustingspringandtryagain.
• Oncethewireisexposed,releasethewirefeedbutton[6]orthetrigger
• Slidethecontacttipoverthewireandscrewitintotorchhandle
• Replacethenozzleandcutoffanyexcesswireover10mm
MIG MODE

POLARITY SELECTION
• Thecorrectpolaritymustbesetforthetypeof
welding.
When using solid wire in conjunction with weld-
ing gas, connect the torch to the positive ter-
minal and the earth clamp to the negative. See
diagram A.
When using ux cored wire (gasless) connect
the negative terminal to the welding torch and
the earth clamp to the positive. see diagram B.
CAUTION! Check that the dinse terminals are tight before
commencing to weld to prevent burning
To commence the welding process proceed as follows.
• MakesurethattheearthclampisrmlyconnectedtotheWorkpiece.
WARNING! Ensure that you have your protective clothes, gloves and welding helmet
correctly tted before welding. Do not start welding before your eyes are properly pro-
tected by the welding helmet.
• TurnthewelderswitchedONandtheweldinggasifapplicable.
You are now ready to execute the weld.
• Selecttherequiredweldingvoltage[7]settingweldforthejobathand.
• Bringthewireintocloseproximityoftherequiredweldstartposition.Keepthetipapproximately10-15mm
awayfromtheworkpieceandsqueezethetriggeronthetorchtocommencewelding.
• Adjustthewirefeed[8]ratetoobtaintheoptimumweld
2 STEP / 4 STEP
The 2 STEP /4 STEP switch [5] controls how the machine reacts to the trigger switch on the weld-
ing torch.
2 STEP mode
• Squeezethetriggertostartweldingandreleaseittostop.
4 STEP mode
• Squeezethetriggerandreleasetostartwelding.ToStop,Squeezethetriggerandreleaseagain
A B