Jefferson JEFMIG151-A User manual

User Manual
v.1.1
JEFMIG151-A

3
USER MANUAL
JEFMIG151-A
151A MIG WELDER - 230V~ 50Hz
www.jeffersontools.com
1. Contents
Important: Please read all these instructions before operating this product and save these instructions. This manual has been
compiled by Jefferson Tools and is an integrated part of the product with which it's enclosed and should be kept with it for the
future reference.
This manual describes the purpose for which the product has been designed and contains all the necessary information to ensure
its correct and safe use. We recommend that this manual is read before any operation or, before performing any kind of adjustment
to the product and prior to any maintenance tasks. By following all the general safety instructions contained in this manual you will
help to ensure operator safety and extend the potential lifespan of the equipment.
All photographs and drawing in this manual are supplied by Jefferson Tools to help illustrate the operation of the product. whilst
every effort has been made to ensure accuracy of information contained in this manual our policy of continuous improvement
determines the right to make modifications without prior warning.
1. Contents 3
2. Introduction & Specification 4
3. Safety Guidelines 4
4. Assembly 7
5. Welding Power: Voltage & Current Characteristics 7
6. Equipment Overview 8
7. Ratings Plate 9
8. Preparation 10
9. Control Panel 11
10. Gasless Operation 12
11. Conversion to MIG (Gas) Welding 12
12. Welding Guidelines 14
13. Operation Guidelines 15
14. Maintenance 16
15. Troubleshooting 18
16. Parts Diagram & Listing 19
Limited Warranty Statement 20
EC Declaration of Continuity 22

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USER MANUAL
JEFMIG151-A
151A MIG WELDER - 230V 50Hz
www.jeffersontools.com
IMPORTANT: These instructions contain the information you require to prepare your machine for welding, together with a
maintenance and a troubleshooting section. The instructions are not intended to teach you how to weld. If you have no
experience, we recommend that you seek training from an expert source. MIG welding is relatively easy, but does require a steady
hand and supervised practice on scrap metal, as it is only with continued practice that you will achieve the desired results.
INTRODUCTION: Our professional range of autoMIG welders all feature a heavy-duty high output transformer and forced air
cooling to maximise duty cycle performance. AutoMIG 151 is supplied with a comfort grip non-live torch, 1.8mtr earth cable,
1mtr gas hose, 0.45kg ux cored wire and 1.0mm contact tip. This unit is supplied set up in the gasless mode but can be
switched easily to use with gas by a simple change of polarity, and the purchase of a gas conversion kit.
Model Number JEFMIG151-A Wire Diameter Fluxed Cored: 0.8 - 0.9mm (Gasless)
Input Voltage 230V 1ph Steel Wire: 0.6 - 0.8mm
Frequency 50Hz Net Weight 26kg
Output Current Range 30-150A Box Dimensions 720 x 320 x 540mm
Rated Duty Cycle* 100% @ 30A, 15% @ 105A Cooling System Forced Air
Absorbed Power 4.5kW Torch Non-live
Gas Type CO2 / Argon Mix & Argon & CO2
*Duty cycle is the ratio of the uninterrupted on-load duration to the total time (10 minutes in this case). It lies between a range of
0 and 1, and can be expressed as a percentage. For example, in the case of a 60% duty cycle, a load is applied continuously for
6 min followed by a no-load period of 4 min.
2. Introduction & Specification
3.1. ELECTRICAL SAFETY
• WARNING! It is the user’s responsibility to read, understand and comply with the following:
You must check all electrical equipment and appliances to ensure they are safe before using. You must inspect power supply leads,
plugs and all electrical connections for wear and damage. You must ensure the risk of electric shock is minimised by the installation
of appropriate safety devices. An RCCB (Residual Current Circuit Breaker) should be incorporated in the main distribution board. We
also recommend that an RCD (Residual Current Device) is used with all electrical products. It is particularly important to use an RCD
together with portable products that are plugged into an electrical supply not protected by an RCCB. If in doubt consult a qualied
electrician. You may obtain a Residual Current Device by contacting your Jefferson dealer. You must also read and understand the
following instructions concerning electrical safety.
3.1.1. The Electricity At Work Act 1989 requires all portable electrical appliances, if used on business premises, to be tested by a
qualied electrician, using a Portable Appliance Tester (PAT), at least once a year.
3.1.2. The Health & Safety at Work Act 1974 makes owners of electrical appliances responsible for the safe condition of
the appliance, and the safety of the appliance operator. If in any doubt about electrical safety, contact a qualified
electrician.
3.1.3. Ensure the insulation on all cables and the product itself is safe before connecting to the mains power supply. See 3.1.1. &
3.1.2. above and use a Portable Appliance Tester (PAT).
3.1.4. Ensure that cables are always protected against short circuit and overload.
3.1.5. Regularly inspect power supply leads, plugs and all electrical connections for wear and damage and especially power
connections, to ensure that none is loose.
3.1.6. Important: Ensure the voltage marked on the product is the same as the electrical power supply to be used and check that
plugs are tted with the correct capacity fuse. A 13 amp plug may require a fuse smaller than 13 amps for certain products,
see fuse rating at right.
3. Safety Guidelines

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USER MANUAL
JEFMIG151-A
151A MIG WELDER - 230V~ 50Hz
www.jeffersontools.com
3.1.7. DO NOT pull or carry the powered appliance by its power supply lead.
3.1.8. DO NOT pull power plugs from sockets by the power cable.
3.1.9. DO NOT use worn or damaged leads, plugs or connections. Immediately
replace or have repaired by a qualied electrician. A U.K. 3 pin plug must be
tted according to the following instructions. (UK only - see diagram at right).
Ensure the unit is correctly earthed via a three-pin plug.
a) Connect the green/yellow earth wire to the earth terminal ‘E’.
b) Connect the brown live wire to live terminal ‘L’.
c) Connect the blue neutral wire to the neutral terminal ‘N’.
d) After wiring, check that there are no bare wires, that all wires have
been correctly connected, that the cable external insulation extends
beyond the cable restraint and that the restraint is tight.
3.1.10. Some products require more than a 13 amp electrical supply. In such a case, NO plug will be tted. You must contact a
qualied electrician to ensure that a 30 amp fused supply is available. We recommend you discuss the installation of an
industrial round pin plug and socket with your electrician.
3.1.11. Exposed live conductors or other bare metal in the welding circuit, or in unearthed, electrically-live equipment can fatally
electrocute a person whose body becomes a conductor.
3.1.12. Do not stand, sit, lie, lean on, or touch a wet surface when welding, without suitable protection.
3.1.13. Magnetic elds from high currents can affect pacemaker operation. Persons wearing electronic life support equipment
(pacemaker) should consult with their doctor before going near arc welding, gouging, or spot welding operations.
3.1.14. Keep body and clothing dry. Never work in a damp area without adequate insulation against electrical shock. Stay on a
dry duckboard, or rubber mat when dampness or sweat can not be avoided. Sweat, sea water, or moisture between the
body and an electrically-live part - or earthed metal - reduces the body surface electrical resistance, enabling dangerous
and possibly lethal currents to ow through the body.
3.1.15. Cable extension reels. When a cable extension reel is used it should be fully unwound before connection. A cable reel
with an RCD tted is recommended since any product which is plugged into the cable reel will be protected. The section
of the cable on the cable reel is important and should be at least 1.5mm², but to be absolutely sure that the capacity of
the cable is suitable for this product and for others that may be used in the other output sockets, we recommend the use
of 2.5mm² section cable.
• WARNING! Be very cautious if using a generator to power the welder. The generator must be self-regulating and stable
with regard to voltage, wave form and frequency. The output must be greater than the power consumption of the welder.
If any of these requirements is not met the electronics within the welder may be affected.
NOTE: The use of an unregulated generator may be dangerous and will invalidate the warranty on the welder.
• WARNING! The welder may produce voltage surges in the mains supply which can damage other sensitive equipment
(e.g. computers). To prevent this happening, it is recommended that the welder is connected to a power supply that does
not feed any sensitive equipment.
3.2. ELECTROMAGNETIC INTERFERENCE
This equipment is fully tested and compliant with EC Directive 2014/30/EU: Electromagnetic Compatibility (EMC) regulations,
however it is important that the user takes responsibility when using the equipment to ensure that electromagnetic disturbances
are minimised or prevented.
Before using the welding equipment you should make an assessment of potential electromagnetic problems in the working
environment. Examples of unsuitable working environments include:
a) areas where other supply cables, control cables, signalling and telephone cables are present
b) in the vicinity of radio and television transmitters and receivers;
c) near computers and other control equipment;
d) areas where medical or safety equipment are present (for example pacemakers and hearing aids etc)
e) environments containing equipment used for calibration or measurement;
Please note: Electromagnetic interference can be caused by devices outside the immediate working environment and
neighbouring rooms and buildings should be assessed for potential issues prior to work commencing.
YELLOW & GREEN
EARTH WIRE
BROWN
LIVE
WIRE
BLUE
NEUTRAL
WIRE
CABLE
RESTRAINT
FUSE RATING
13 AMP

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USER MANUAL
JEFMIG151-A
151A MIG WELDER - 230V 50Hz
www.jeffersontools.com
3.3. ENVIRONMENTAL CONDITIONS
Note: Ambient air should be free from abnormal amounts of dust, acids, corrosive gases or substances etc. other than those
generated by the welding process itself:
• Working ambient air temperature range: -10°C (to) +40°C
• Ambient air temperature range for transport and storage: -25°C (to) +55°C
• Relative humidity: up to 50% at 40°C and 90% at 20°C
• Altitude above sea level up to 1000m.
3.4. GENERAL SAFETY
• DANGER! Unplug the welder from the mains power supply before performing maintenance or service.
• OPERATORS MUST RECEIVE ADEQUATE TRAINING BEFORE USING THE WELDER.
• Keep the welder and cables in good working order and condition. Take immediate action to repair or replace damaged parts.
• Use genuine parts and accessories only. Unapproved parts may be dangerous and will invalidate the warranty.
• Use an air hose to regularly blow out any dirt from the liner and keep the welder clean for best and safest performance.
• Check and spray the gas cup and contact tip regularly with anti-spatter spray, available from your Jefferson dealer.
• Locate welder in a suitable work area. Ensure that the area has adequate ventilation as welding fumes are harmful.
• Keep work area clean, tidy and free from unrelated materials. Also ensure the working area has adequate lighting and that a
re extinguisher is at hand.
WARNING! Use welding head shield to protect eyes and avoid exposing skin to ultraviolet rays given off by electric arc.
Wear safety welding gauntlets.
• Remove ill tting clothing, remove ties, watches, rings and other loose jewellery and contain long hair.
• Ensure the workpiece is correctly secured before welding.
• Avoid unintentional contact with the workpiece. Accidental or uncontrolled use of the torch may be dangerous and will wear
the nozzle.
• Keep unauthorised persons away from the work area. Any persons working within the area must wear a protective head
shield and gloves.
• Operators must receive adequate training before using the welder.
• Stand correctly keeping a good footing and balance, ensure the oor is not slippery and wear non-slip shoes.
• DO NOT operate the welder if it or the cables are damaged and DO NOT attempt to t any unapproved torches or other
components to the welder.
• DO NOT get welder wet or use in damp or wet locations or areas where there is condensation.
DANGER! DO NOT weld near flammable solids, liquids or gases and DO NOT weld containers or pipes which have held
flammable materials. Avoid welding materials which have been cleaned with chlorinated solvents or welding near such
solvents.
• DO NOT stand welder on a metal workbench, car bodywork or similar.
• DO NOT touch any live metal parts of the torch or electrode while the machine is switched on.
• DO NOT pull the welder by the cable, or the torch. Protect cables from sharp or abrasive items. DO NOT bend, strain or
stand on cables or leads. Protect from heat. Long lengths of slack must be gathered and neatly coiled. DO NOT place cables
where they endanger others.
• DO NOT touch the torch or workpiece immediately after welding as they will be very hot. Allow to cool.
• DO NOT operate welder while under the inuence of drugs, alcohol or intoxicating medication, or if tired.
• When not in use store the welder in a safe, dry, childproof area.
3.5. GAS SAFETY
• Store gas cylinders in a vertical position only and ensure the storage area is correctly secured.
• DO NOT store gas cylinders in areas where the temperature may exceed 50°C. DO NOT use direct heat on a cylinder.
Always keep gas cylinders cool.
• DO NOT attempt to repair or modify any part of a gas cylinder or valve and DO NOT puncture or damage a cylinder.
• DO NOT obscure or remove any ofcial labels on a cylinder. Always check the gas identity before use. Avoid getting gas
cylinders oily or greasy.
• DO NOT lift a cylinder by the cap, guard or valve. Always keep caps and guards in place and close valve when not in use.
3. Safety Guidelines (continued)

7
USER MANUAL
JEFMIG151-A
151A MIG WELDER - 230V~ 50Hz
www.jeffersontools.com
The curve shown in Fig.3 below shows “V-A” the external static characteristic of welding power, gradient of curve named slope,
normal means “drop off voltage per 100A”. The curves show the output voltage obtainable in any preset output current because
the “V-A” slope is fixed.
500
0
10
20
30
40
U2(V)
I2(A)
Fig.3: JEFMIG151-A Static external characteristic curve
100 150 200 250
4.1 Assembly of wheels: (See fig.2)
4.1.1 Drop the axle brackets (7) through the slots in the rear of the bottom tray (6).
4.1.2 Attach a circlip (9) to one end of the axle (10) and slide a wheel (8) onto the axle and right up to the circlip.
4.1.3 Pass the axle (10) under the tray (6) and through the two protruding brackets (7) until the rst assembled wheel is up against
the side of the tray.
4.1.4 Slide the other wheel (8) onto the other end of the axle (10) and secure it by attaching a circlip (9) to the end of the axle.
4.2. Assembly of front foot: (See fig.2)
4.2.1 Place the foot (5) onto the underside of the tray (6) ensuring that the three holes on the foot align with the holes in the tray.
Fix the foot in place with three self tapping screws.
4.3 Assembly of handle: (See fig.1)
4.3.1 Attach the rear handle bracket (1) to the top of the casing using two self tapping screws. Slide the straight handle (2) into the
bracket (1) and slide the other bracket (3) onto the front end of the handle. Secure bracket (3) with two self tapping screws.
Insert the handle extension (4) into the front end of the handle and secure it with a self tapping screw.
4. Assembly
5. Welding Power: Voltage and Current Characteristics
FIG. 1
FIG. 2

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USER MANUAL
JEFMIG151-A
151A MIG WELDER - 230V 50Hz
www.jeffersontools.com
The following summary provides a brief overview of the front switch panel (see Fig.4). If you have any additional questions relating
to the equipment please contact your nearest Jefferson Dealer before using the equipment.
6.1. “ON/OFF” switch
When the switch is in the “OFF” position it means power has been shut off to the welder, when the switch is in the ”ON”
position it means power is supplied to the main transformer and control circuit.
6.2. “MIN/MAX” switch
The “MIN/MAX” and "1/2" switches are on the front panel of the machine. Each have two settings. You can choose different
setting combinations of the two switches according to the metal thickness.
6.3. Wire speed control knob
Used to control the wire speed: turn clockwise to increase the wire speed or counter-clockwise to decrease the wire
speed. The numbers (0-10) around the knob show the wire feed speed. The rated wire feed speed for this equipment is
1.8m/min ~ 11.4m/min.
6.4. Overload light
If you are welding with a large current for a long time and exceed the duty cycle, the overload lamp will light (yellow), and
the welder will automatically shut down until it cools down. If this happens, you must stop welding and wait approximately
5 minutes, before the unit will reset and allow you to continue welding.
6. Equipment Overview
OVERLOAD LIGHT
"MIN / MAX"
SWITCH
"ON / OFF"
SWITCH
"1/2"
SWITCH
POWER CORD
WIRE SPEED
CONTROL KNOB
TORCH CABLE
GROUNDING
CABLE
Fig.4 Front Switch Panel

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USER MANUAL
JEFMIG151-A
151A MIG WELDER - 230V~ 50Hz
www.jeffersontools.com
JEFMIG151-A
7. Ratings Plate
On the front panel of the welder is the ratings plate, giving the following data:
1: The BS/EU standard relating to the safety and construction of arc welding and associated equipment.
2: Single phase transformer – rectier.
3: Symbol indicates welding with a continuous ow of welding wire.
4: Symbol for Single-phase AC supply.
5: Rating of internal protection provided by casing.
6: Output U0Rated minimum and maximum no load voltage.
I2, U2Current and corresponding voltage.
X Welding ratio based on a 10 minute cycle.
20% indicates 2 minutes welding and 8 minutes rest,
100% would indicate continuous welding.
7: Mains Supply U1Rated supply voltage and frequency.
I1max Maximum current.
I1eff Maximum effective current.
8: Welding current range.
9: Serial Number. Specically identies each welder.
1
9
2
3
4
5
8
6
7

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USER MANUAL
JEFMIG151-A
151A MIG WELDER - 230V 50Hz
www.jeffersontools.com
8. Preparation
8.1 Fitting a reel of wire:
8.1.1 Lift the black catch on the side of the welder and open the side compartment to gain access to the wire feed unit mechanism
and the wire spool holder. See g.5. The welder is supplied with a mini spool containing 0.45kg of ux cored wire.
8.1.2 Referring to g.7, rotate the buttery nut (5) anti-clockwise and remove it from the threaded spindle together with the
pressure disc (4). Leave the spring (1) on the spindle (2).
8.1.3 Place the wire reel (3) over the spindle and down onto the spring ensuring that the wire will withdraw from the top of the
spool in a forwards direction towards the wire feed unit.
8.1.4 Push lightly down on the top of the reel of wire and screw the pressure disc (4) onto the end of the spindle and down
onto the top of the wire reel. The reel take off pressure should be set to provide a mild braking effect to prevent overrun
where loose coils of wire form on the reel. Do not overtighten the pressure disc as too much braking will conict with the
wire tension set on the wire drive unit. Lock the position of the pressure disc by screwing the buttery nut (5) down on
top of it.
8.1.5 Referring to g.5 turn the knob on the wire lock screw (C) anti-clockwise and lift it up and away from the pressure roller
moulding. Swing the pressure roller moulding (D) away from the drive roller.
8.1.6 Release the wire from the spool (do not allow wire to uncoil) and straighten 40-50mm of wire and gently push through the
exible plastic guide and through the 0.9mm feed roller groove and into the torch liner. Refer to maintenance section 14.3
on how to reverse or change the roller for driving other wire diameters.
8.1.7 Referring to g.6, move the pressure roller moulding back round onto the grooved drive wheel and swing the wire lock
screw back down to lock it in place. See section 8.2 regarding wire tension.
8.1.8 Feeding the wire through to the torch. (See g.8) Remove gas cup (a) and contact tip (b) from end of torch as follows:
a) Take torch in left hand with the torch tip facing to the right.
b) Grasp gas cup rmly in your right hand.
c) Turn gas cup clockwise only and pull cup out to the right.
WARNING! do not turn gas cup anti-clockwise, as this will damage internal spring.
d) Unscrew the copper contact tip (right hand thread) to remove.
8.1.9 Check welder is switched “OFF” and that the earth clamp is away from the torch tip. Connect the welder to the mains
power supply and set the current switch to MAX.
8.1.10 Set the wire speed knob to position 5 or 6. See g.9. Switch welder on. Keeping the torch cable as straight as possible
and press the torch switch. The wire will feed through the torch.
8.1.11 When wire has fed through, switch welder off, unplug from mains.
a) Take torch in left hand, slide the contact tip over the wire and screw it back into place.
WARNING:
The following steps require applying power to the welder. Do not touch anything with the torch handle or an
arc may be ignited. Do not operate the welder when the casing has been opened for maintenance.
FIG. 5
FIG. 6

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USER MANUAL
JEFMIG151-A
151A MIG WELDER - 230V~ 50Hz
www.jeffersontools.com
8. Preparation
b) Grasp gas cup in right hand, push onto
torch head and turn clockwise only.
WARNING! do not turn gas cup anti-
clockwise, as this will damage internal
spring.
c) Cut wire so that it is just protruding from
the cup.
8.2. Setting wire tension.
IMPORTANT: You must set the correct
tension, too little or too much tension will
cause problematic wire feed and result
in a poor weld. Turn the wire lock screw
clockwise to increase the tension and
anticlockwise to decrease the tension as
shown in g.6.
8.2.1 Correct tension between the rollers
is checked by slowing down the wire
between gloved ngers. If the pressure
roller skids the tension is correct. Try to
use the lowest tension possible as too
high a tension will deform the wire. When
you have completed welding allow the
welder to cool before storing in a safe, dry
place. Note: Damaged torches and cables
are not covered under warranty.
9.1 Thermal overload light. (see g.9) If the duty cycle is exceeded as a result of
welding too long with a high current the yellow overload light will illuminate
and the welder will turn off. When the welder has cooled down (approx. 5 to 10
minutes) the power will be restored and welding can recommence.
9.2 Power ON/OFF switch. (see g.9) When the power is ON the green switch will be
illuminated. When the welder is no longer required it should be switched to the
OFF position and the power plug should be disconnected from the mains supply.
9.3 Current switches MIN, MAX & 1, 2. (see g.9) Used together these two switches
provide 4 increasing power levels as follows: MIN/1, MIN/2, MAX/1, MAX/2.
9.4 Wire speed control knob. (see g.9) As a general rule, a higher current requires a
higher wire speed.
FIG. 7
FIG. 8
9. Control Panel
FIG. 9

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USER MANUAL
JEFMIG151-A
151A MIG WELDER - 230V 50Hz
www.jeffersontools.com
• WARNING! ENSURE THAT YOU READ, UNDERSTAND AND APPLY SAFETY
INSTRUCTIONS BEFORE OPERATING THE WELDER. IF WELDING A VEHICLE,
DISCONNECT THE BATTERY OR FIT AN ELECTRONIC CIRCUIT PROTECTOR.
10.1 Polarity check: Ensure that the welder is disconnected from the main power
supply, open the side panel and check that the polarity is correctly set up for
gasless operation. The earth clamp wire must be connected to the POSITIVE (+)
terminal and the power (torch) lead must be connected to the NEGATIVE (-)
terminal as shown in g.10.
10.2 To ensure a complete circuit, the earth clamp must be securely
attached to the workpiece.
a) The weld area must also be free of paint, rust, grease, etc.
b) Obtain the best connection by grinding the point of contact on the workpiece before connecting the clamp.
10.3 If welding a vehicle, disconnect the battery or t a “Electronic Circuit Protector” (available from your Jefferson dealer).
10.4 Set up the current switches to give the required power setting and adjust the wire speed accordingly.
10.5 During the welding process, wire drawn from the spool is automatically fed through an insulated liner in the torch cable
to the torch tip. The torch switch activates the wire feed roller (to stop wire feed release the switch). As wire comes into
contact with the workpiece an arc is struck. The arc melts the wire which is deposited into the weld.
For welding stainless steel or aluminium, this welder can be converted to a conventional
mig welder. To convert to gas, order a reel of regular wire, a bottle of suitable gas, tips and
nozzles and a conversion kit containing a regulator plus connection hoses, hose adaptor
and jubilee clips (see g.12) from your local Jefferson dealer.
11.1 Check Polarity: Ensure that the welder is disconnected from the mains power
supply and open the side panel and check that the polarity is correctly set up for
gas operation. The earth clamp wire must be connected to the NEGATIVE (-)
terminal and the power (torch) lead must be connected to the POSITIVE (+)
terminal as shown in g.11.
11.2 Check wire feed roller: If necessary, change and/or turn the wire feed roller (See
maintenance section 14) so that the appropriately sized groove is in line with the
drive path i.e. in the groove nearest to you.
11.3 Fit required wire: Fit a reel of steel or aluminium wire (either 0.6 or 0.8mm).
11.4 Set the wire tension as described in section 8.2.
11.5 Mount the gas cylinder: Strap the gas cylinder to the back of the machine. Two nylon straps are provided to hold small
cylinders in place. Thread the straps through the raised metal xing loops on the back of the welder. Stand the gas
cylinder on the rear platform and x the straps around it as shown in g.12.
11.5.1 Close the ow regulator before screwing it onto the cylinder. Screwing down the regulator will automatically open the
cylinder valve. When the sound of gas escaping is heard screw the regulator one further turn only. This will be sufcient
to seal the cylinder.
WARNING! Excessive tightening of the flow regulator will over-compress the rubber sealing washer and allow the
gas to escape slowly without being detected.
11.6 Connect gas cylinder to welder gas input. Push the small adaptor into one end of the larger diameter hose. Push the
other end of the hose onto the ribbed gas input connector on the back of the welder. Secure both ends of the hose with
the jubilee clips provided. Push one end of the smaller diameter gas hose into the open end of the adaptor and push the
other end into the regulator outlet, it will seal automatically. See g. 12. To release the gas hose, press the collet inwards
on the quick couplers and pull the hose out.
10. Gasless Operation
11. Conversion to MIG (Gas) Welding
FIG. 10
FIG. 11

13
USER MANUAL
JEFMIG151-A
151A MIG WELDER - 230V~ 50Hz
www.jeffersontools.com
11.6.1 Turn the gas regulator knob halfway for a 2ltr/min ow and all the way for
maximum ow of 4ltr/min.
11.6.2 Always remove the ow regulator after use if the machine is to be stored
for any length of time.
11.7 Gas types. Welding mild steel with CO² gas is appropriate for most
welding tasks where spatter and high build up of
weld do not pose a problem. To achieve a spatter-free and at weld
however, you must use an CO²/Argon mixture.
To weld aluminium use:
• Argon gas • 0.8mm Contact Tip • 0.8mm Aluminium Wire (MIG/2/
KAL08)
11.8 Cylinder sizes. The platform at the rear of the welder will support cylinders
up to a diameter of 140mm, a height of 500mm and a maximum weight
of 10kg. If you wish to use larger cylinders they must be properly secured
to a separate welding trolley. An industrial gas cylinder adaptor kit will be
required. Contact your local Jefferson dealer to order these items.
11.8.1 The following table is an estimated duration of cylinders based on a ow
rate of 2 litres per minute. Actual duration will be dependant upon various
job conditions including the operator’s welding technique. All times are
therefore approximate.
11.9 Mig/Mag gas welding principles: Welding wire is automatically fed through an insulated liner to the tip of the torch. The
torch consists of a switch, liner, gas hose, and control cable. The switch activates the wire feed roller and the gas ow.
Releasing the switch stops the wire feed and gas ow. The weld current is transferred to the electrode (the wire) from the
contact tip at the torch end. The current switches (see section 9.3) control the current to the electrode. Wire speed must
be adjusted according to current output. The higher the current the faster the wire speed. A gas cup ts over the contact
tip to direct gas ow towards the weld, ensuring that the arc welding process is shielded from oxidisation. The shielding
gas also assists heating of the weld. The torch is connected to the positive side of a DC rectier, and the negative clamp
is attached to the workpiece.
Disposable cylinders:
CO²/100 390g = 1-1/4hours. CO²/101 600g = 2 hours.
Argon ARG/100 300g = 1hour. Argon/CO² MIX/100 300g = 1 hour.
Note: When comparing prices, always check ll weights.
FIG. 12

14
USER MANUAL
JEFMIG151-A
151A MIG WELDER - 230V 50Hz
www.jeffersontools.com
PRECAUTIONS
• Ensure that there is free air circulating around the outer casing of the welder, and that the air vents are unobstructed.
• Welding arc can seriously damage your eyes. Both the operator and spectators must always use a suitable welding face
shield or helmet, with suitable lter lenses for the welding processes.
• Suitable Personal Protection Equipment (PPE) including gloves and working clothes should be worn at all times.
• Always check and ensure that the pressure regulator and gauges (if tted) are working correctly before use.
• Regulators are designed to be used with specic gases, it is important that you use the correct regulator for the gas required.
• Do not lubricate the regulator.
• Inspect gas hoses, cables and clamps before use to ensure they are in good condition.
• Remove all ammable materials from the working environment before use.
• Keep a re extinguisher nearby at all times. The extinguisher should be Dry Powder or CO2type.
• Do not remove any of the casing panels for repair or maintenance unless the machine is disconnected from the supply,
and never use the machine with any of the panels removed. All repairs should be carried out by qualied engineers using
Jefferson approved parts. Contact your nearest Jefferson Dealer for details.
• Never use or store this equipment in a wet or damp environment and do not expose the equipment to rain during use.
• The MIG welding process uses an inert gas to protect the weld pool. It is important to ensure the appropriate gas is being used.
• Never use an unknown or unidentiable gas supply or gas from a damaged or unmarked cylinder.
• Do not lift or move a gas cylinder by holding he cylinder by the valve.
• Do not expose the cylinder to a heat source or sparks while in storage or in use.
• Stop welding immediately if any static / electric shocks are felt or detected. Do not attempt to weld using the equipment until
the source of the fault is identied and repaired.
• Do not point the MIG torch at anyone when in use.
• Do not touch the MIG torch nozzle until the welder is switched OFF and the nozzle has been allowed to cool off.
• Never connect, disconnect, or attempt to service the MIG torch, until the machine is switched OFF and disconnected from
the mains power supply.
• Never allow the equipment cables to become wrapped around the operator or any bystanders in the working environment.
12. Welding Guidelines
IMPORTANT: These instructions are not intended to teach you how to weld. If you have no experience, we recommend that you
seek training from an expert source. MIG welding is relatively easy, but does require a steady hand and supervised practice on
scrap metal, as it is only with continued practice that you will achieve the desired results.
12.1 Mig/Mag welding:
Welding wire is automatically fed through an insulated liner to the tip of the torch. The torch consists of a switch, liner,
and control cable. The switch activates the wire feed roller. Releasing the switch stops wire feed. The weld current is
transferred to the electrode (the wire) from the contact tip at the torch end. The current to the electrode is set using the
rocker switch on the front of the control panel. Wire speed must be adjusted according to current output using the rotary
control positioned to the left of the control panel. The higher the current the faster the wire speed. The torch is connected
to the positive side of a DC rectier, and the negative clamp is attached to the workpiece.
12.2 Preparation for welding: IMPORTANT! BEFORE YOU COMMENCE, MAKE SURE THE MACHINE IS SWITCHED OFF
AT THE MAINS. IF WELDING A CAR, DISCONNECT THE BATTERY OR FIT AN ELECTRONIC CIRCUIT PROTECTOR.
ENSURE THAT YOU READ, UNDERSTAND AND APPLY THE SAFETY INSTRUCTIONS IN SECTION 3.
12.2.1 To ensure a complete circuit, the negative lead must be securely attached to the workpiece close to the weld area. Best
connection is obtained by grinding the point of contact on the workpiece before connecting the clamp.
12.2.2 The weld area must be free of paint, rust, grease, etc.
12.3 Thermal Protection:
Should the welder become overheated due to prolonged use beyond the stated duty cycle the thermal protection will
cause the welder to cut out and the orange light on the front panel will illuminate (as shown in Fig.9 on page 11).
Wait for fteen minutes for the welder to cool down at which time it will reconnect automatically.

15
USER MANUAL
JEFMIG151-A
151A MIG WELDER - 230V~ 50Hz
www.jeffersontools.com
13. Operation Guidelines
Before welding:
• Read and understand the safety rules section of this manual
• Ensure all ammable materials are removed the work area
• Ensure there is good ventilation around the welding unit and the working environment
• Enure you have a re-extinguisher in the vicinity of the working environment and that it is ready for use in the event of re
• Wear appropriate protective clothing and insulated leather gloves (check with your nearest Jefferson Dealer for advice)
Step 1:
Connect work clamp onto metal to be welded, or to the metal workbench where the object is mounted and electrically connected.
Step 2:
Before plugging in, adjust the amperage and wire feed speed according to material type and thickness, and the wire size.
Step 3:
Check the power switch is in the OFF position, and then plug the power cable into the electrical outlet.
Step 4:
While holding the torch with the wire and tip clearly out of the way of any grounded objects, turn the power switch to ON position.
Step 5:
Position yourself in the area to be welded, and then place the face shield over your eyes.
Step 6:
Press (and hold) the torch button and stroke the area to be welded with the
electrode wire to ignite the arc.
Step 7:
Once the arc is ignited, tilt the electrode wire forward at an angle of
approximately 35° (as shown in Fig.13).
Step 8:
When the weld is complete, release the torch button and lift the wire clearly
away from any grounded object, set the Face Shield down and turn the
Power Switch to the “OFF” position.
Step 9:
Unplug the Power Cord from the electrical outlet.
WARNING: WEAR APPROPRIATE PERSONAL PROTECTION EQUIPMENT AT ALL TIMES
Never look at the ignited arc without approved, arc shaded, eye protection in a full-face shield. Permanent
eye damage or blindness can occur. Skin burns can occur. Never breathe arc fumes.
Fig.13 Electrode wire angle

16
USER MANUAL
JEFMIG151-A
151A MIG WELDER - 230V 50Hz
www.jeffersontools.com
14. Maintenance
Periodically open the access panel from the unit and, using compressed air, blow out all dust and debris from the interior.
Inspect all air vents and cooling slots to ensure that they are clean and unobstructed.
Always store the welder in a clean, dry, safe location out of reach of children and other unauthorized people.
14.1. Wire feed unit:
14.1.1 Check the wire feed unit at regular intervals. The feed roller wire guide plays an
important part in obtaining consistent results. Poor wire feed affects the weld.
Clean the rollers weekly, especially the feed roller groove, removing all dust
deposits.
14.2. Torch:
14.2.1 Protect the torch cable assembly from mechanical wear. Clean the liner from
the machine forwards by using compressed air. If the liner is blocked it must
be replaced.
14.3. Turning feed roller IMPORTANT: Turn the feed roller to suit the wire size.
14.3.1 There are two grooves on the feed roller, 0.6mm and 0.9mm. Always have
the groove that is being used on the outside of the roller (nearest to you). To
turn the feed roller rst loosen the wire tension knob and move it into its up
position (see g.14-1) then move the tensioning roller assembly to its down
position (see g.14-2). Take hold of the triangular knob on the roller retainer
and rotate it 90°anticlock wise to release it as shown in g.14.3. Now pull
the roller retainer off the drive spindle to reveal the roller as shown in g.15.
Pull the roller off the drive spindle, ip it over and put it back on the drive
spindle. (See g.16) The groove size you require should now be visible on
the face of the roller. Push the roller retainer back onto the drive spindle with
the opening facing right. Ensure that the anges at the base of the retainer,
seat fully into the circular recess in the main moulding and then rotate the
retainer through 90° to lock it in place.
14.4. Contact tip (to remove tip follow steps in 6.1.8):
14.4.1 The contact tip is a consumable item and must be replaced when the bore
becomes enlarged or oval. The contact tip MUST be kept free from spatter.
14.5. Gas cup (to remove cup follow steps in 6.1.8):
14.5.1 The gas cup must also be kept clean and free from spatter. Build-up of
spatter inside the gas cup can cause a short circuit at the contact tip which
will result in expensive machine repairs.
14.6. Replacing wire liner:
14.6.1 A worn or damaged wire liner will seriously affect the performance of the
welder and should be immediately replaced. First wind the wire back onto
the spool and secure it. Remove the four screws securing the torch cable
clamp to the wire feed unit (g.17) and take off the clamp.
14.6.2 To open the torch case rst take hold of the locking ring (g.18-5) and turn
it anticlockwise until it stops and then pull it off the two halves of the torch
case and slide it a little way down the torch cable.
14.6.3 Lift up the back of the upper torch moulding as shown in g18-1 and
unhook it from the front of the lower moulding (see 7 in g.18) and lift it off.
14.6.4 Move the lower moulding away from the inner torch assembly as shown in
g19-4.
WARNING:
Before performing any maintenance on the Welder, unplug the Power Cable from the electrical outlet and
allow all parts of the welder to cool thoroughly
FIG. 16
FIG. 15
FIG. 14

17
USER MANUAL
JEFMIG151-A
151A MIG WELDER - 230V~ 50Hz
www.jeffersontools.com
14.6.5 Disconnect the black liner from the torch control assembly by
pressing the locking ring into the connector and withdrawing the
liner. See A in g.19.
14.6.6 With the torch cable as straight as possible pull the liner from the
torch cable.
14.6.7 Insert the new liner into the torch cable and secure it in the wire
drive unit by replacing the torch cable clamp. See g.17. Insert
the other end of the liner through the locking ring and fully into the
torch control assembly.
14.6.8 Ensure that the switch moulding (g.19-3) is fully seated down
into the lower moulding (4). Place the torch head assembly (2)
down into the lower moulding and arrange the inner connections
within the moulding. The gas pipe and wire liner will rest into
notches on the inner ribs of the moulding.
The two thin switch wires should be to the left
of the gas pipe and the larger black control
cable should be to the right of the wire liner.
14.6.9 Hook the upper moulding (1) onto the lower
moulding (4) as shown in g.18-7. Close
the upper moulding down onto the lower
moulding ensuring that there are no wires
trapped between the two halves. The two
mouldings should close easily, do not force
them shut.
14.6.10 Once the mouldings are closed slide the
locking ring (g.18-5) up onto them. Turn
the locking ring clockwise to secure the
assembly.
FIG. 17
Parts & Servicing
For Jefferson approved replacement parts contact your
nearest dealer or contact Jefferson tools
Telephone: [phone]
Fax: [phone]
Email: [email protected]
FIG. 18
FIG. 19

18
USER MANUAL
JEFMIG151-A
151A MIG WELDER - 230V 50Hz
www.jeffersontools.com
WARNING:
Be certain to shut off the welder, disconnect it from power, and discharge the torch to ground before
adjusting, cleaning, or repairing the unit. Electrical repairs should only be made by a trained technician.
Symptom Possible Cause Corrective Action
No output 1. Duty cycle exceeded
2. Poor work clamp connection
3. Blown breaker or fuse
1. Allow welder to cool until lamp goes out
2. Be sure all connections are secure, and attaching surface is clean
3. Reduce circuit load, reset breaker or replace fuse
Wire tangles at
drive roller
1. Wrong size contact tip
2. Torch liner clogged or damaged
3. Contact tip clogged or damaged
4. Drive roller worn
5. Not enough tension
1. Use proper size contact tip
2. Clean or replace wire liner
3. Clean or replace contact tip
4. Replace drive roller
5. Tighten tension knob
Gun nozzle arcs to
work surface
1. Slag inside gun nozzle
2. Insulation ring melted or expired
1. Clean slag from gun nozzle
2. Replace nozzle
Work clamp and/or
cable gets hot
1. Poor contact
2. Using an extension cord with excessive length
1. Be sure all connections are secure, and welding surface is clean
2. Never use an extension cord longer than 20ft
Wire does not feed 1. Wire jammed
2. Out of wire
3. Not enough tension
4. Wire liner worn
5. Contact tip clogged
1. Reload wire
2. Replace wire spool
3. Tighten tension knob if wire is slipping
4. Replace liner
5. Replace contact tip
Weld pops and
sputters
1. Wire speed setting
2. Contact tip size too large
3. Drive roller slipping
1. Tune in correct setting
2. Replace contact tip
3. Increase tension
Weld current
interrupted
1. Overheating protection activated due to overload 1. Protection automatically resets when transformer has cooled
(approximately 15 minutes)
No weld current 1. Rectier blown
2. Bad connection between clamp and workpiece
3. Break in earth lead
4. Break in torch lead
1. Replace rectier
2. Clean or grind contact surface and weld area
3. Repair or replace earth lead
4. Repair or replace torch lead
Feed motor
not working
1. Gear damaged or worn
2. Motor defective
3. PCB fault
1. Replace gears
2. Replace motor (contact service agent)
3. Replace PCB
Wire does not feed.
Feed roller rotates
1. Pressure roller improperly adjusted
2. Dirt, copper, dust, etc. have collected in torch liner
3. Gas cup (nozzle) or tip defective
4. Deformed wire
1. Adjust tension
2. Clean the liner from the machine forward using compressed air
3. Replace gas cup (nozzle) and/or tip. Check roller tension (Sec 6)
4. Adjust roller tension
Wire feeds unevenly 1. Dirt etc. in liner
2. Gas cup (nozzle) or tip defective
3. Gas cup (nozzle) spattered
4. Feed roller groove clogged
5. Feed roller groove deformed
6. Pressure roller tension incorrect
1. Clean the liner from the machine forward using compressed air
2. Replace gas cup (nozzle) and/or tip
3. Clean or replace gas cup (nozzle)
4. Clean feed roller
5. Replace feed roller
6. Adjust tension
Unstable arc 1. Incorrect settings
2. Impurities in weld area
3. Worn or defective gas cup (nozzle)
1. Check settings
2. Clean and/or grind workpiece
3. Replace gas cup (nozzle)
Porous weld 1. No gas
2. Gas cup clogged
3. Draught blowing away shielding gas
4. Rusty/dirty joints
5. Torch too far from, or at wrong angle to, workpiece
6. Gas leak
7. Faulty electrovalve
1. Open gas cylinder, regulate gas ow
2. Clean or replace gas cup (nozzle)
3. Screen off welding site or increase gas ow
4. Clean and/or grind workpiece
5. Gas cup to workpiece should be 8-10mm. Torch angle approx 75°
6. Check hoses, connections and torch assembly. Press gas cup into position
7. Clean out or replace
Electrode sticking
in gas cup (nozzle)
1. Worn or defective gas cup (nozzle)
2. Wire deformed
3. Wire speed too slow
1. Replace gas cup (nozzle)
2. Check roller tension
3. Increase wire speed
Irregular
weld head
1. Torch incorrectly held
2. Wire weaving in weld pool
1. Use correct torch angle
2. Check roller tension and adjust
Weld bead too
narrow and raised
1. Weld current too low
2. Weld speed too fast
1. Increase power and wire speed
2. Move torch more slowly and weave a little more
Weld bead too wide 1. Weld current too high
2. Weld speed too slow
3. Arc too long
1. Increase power and wire speed
2. Move torch more quickly and weave a little less
3. Bring torch closer to workpiece
Poor penetration 1. Weld current too low
2. Arc too long
1. Increase current and wire speed
2. Bring torch closer to workpiece
Excessive
penetration
1. Weld current too high
2. Weld speed too slow
3. Incorrect distance of torch to workpiece
1. Decrease current and wire speed
2. Move torch faster
3. Torch distance should be 8-10mm
15. Troubleshooting

19
USER MANUAL
JEFMIG151-A
151A MIG WELDER - 230V~ 50Hz
www.jeffersontools.com
16. Parts Diagram & Listing
Parts for gas / gasless MIG Welder 151Amp 230V: Model JEFMIG151-A
ITEM DESCRIPTION ITEM DESCRIPTION
1 Side Panel "B" 22 Filter Reactor
2 Hinge 23 Main Transformer
3 Handle Socket 24 Transformer Bracket
4 Handle 25 Bottom Plate
5 Fan 26 Foot
6 Back Panel 27 Axle Bracket
7 Rectier Bracket 28 Plastic Wheel
8 Clamp 29 Axle
9 Axle 30 Temperature Control
10 Wire Feed Unit 31 Control Circuit Board Bracket
11 Wire Feed Roller 32 Control Circuit Board
12 Side Panel "A" 33 Potentiometer
13 Power Cord 34 Knob
14 Earth Cable with Clamp 35 Nut M6
15 Welding Torch 36 Spring Washer
16 Cover 37 Washer
17 Wire Speed Knob 38 Insulating Washer
18 Switch 39 Screw M6 x 35
19 Overload Indicator 40 Insulating Washer
20 Cable Nib 41 Brace
21 Front Panel 42 8mm O-Ring
PARTS FOR :
GAS/NO-GAS MIG WELDER 150Amp 230V
MODELS: MIGHTYMIG150
ISSUE NO : 2
ISSUE DATE : 07/12/2016

20
USER MANUAL
JEFMIG151-A
151A MIG WELDER - 230V 50Hz
www.jeffersontools.com
Jefferson Professional Tools & Equipment, or hereafter "Jefferson" warrants its customers that its products will be free of defects
in workmanship or material. Jefferson shall, upon suitable notication, correct any defects, by repair or replacement, of any parts
or components of this product that are determined by Jefferson to be faulty or defective.
This warranty is void if the equipment has been subjected to improper installation, storage, alteration, abnormal operations,
improper care, service or repair.
Warranty Period
Jefferson will assume both the parts and labour expense of correcting defects during the stated warranty periods below.
All warranty periods start from the date of purchase from an authorised Jefferson dealer. If proof of purchase is unavailable from
the end user, then the date of purchase will be deemed to be 3 months after the initial sale to the distributor.
1 Year
• All Jefferson MIG Welders
90 Days
• All replacement parts purchased outside of the warranty period
Important: All parts used in the repair or replacement of warranty covered equipment will be subject to a
minimum of 90 days cover or the remaining duration of the warranty period from the original date of purchase.
Warranty Registration / Activation
You can register and activate your warranty by visiting the Jefferson Tools website using the following address:
www.jeffersontools.com/warranty and completing the online form.
Online warranty registration is recommended as it eliminates the need to provide proof of purchase should a warranty claim be
necessary.
Warranty Repair
Should Jefferson confirm the existence of any defect covered by this warranty the defect will be corrected by repair or
replacement at an authorized Jefferson dealer or repair centre.
Packaging & Freight Costs
The customer is responsible for the packaging of the equipment and making it ready for collection. Jefferson will arrange
collection and transportation of any equipment returned under warranty. Upon inspection of the equipment, if no defect can be
found or the equipment is not covered under the terms of the Jefferson warranty, the customer will be liable for any labour and
return transportation costs incurred. These costs will be agreed with the customer before the machine is returned.
*Jefferson reserve the right to void any warranty for damages identified as being caused through misuse
Warranty Limitations
Jefferson will not accept responsibility or liability for repairs made by unauthorised technicians or engineers. Jefferson's liability
under this warranty will not exceed the cost of correcting the defect of the Jefferson products.
Jefferson will not be liable for incidental or consequential damages (such as loss of business or hire of
substitute equipment etc.) caused by the defect or the time involved to correct the defect. This written warranty is the only
express warranty provided by Jefferson with respect to its products.
Any warranties of merchantability are limited to the duration of this limited warranty for the equipment involved. Jefferson is not
responsible for cable wear due to flexing and abrasion. The end user is responsible for routine inspection of cables for possible
wear and to correct any issues prior to cable failure.
LIMITED WARRANTY STATEMENT