Polysoude MU IV Series User manual

THE ART OF WELDING
MU IV
User manual PN-0706056
Open Welding Head
TIG – with or without ller wire , AVC , OSC

THE ART OF WELDING
MU IV
2-80 PN-0706056 Ind. 8
MANUT0309106_rev.1 _25/09/2009
Review of document
Ind. 2 Revision of document
Ind. 3 Update of the graphics standards and equipment compatibility
Ind. 4 Update: Tools box and MU IV wiring plug: AVC/OSC wiring
Ind. 5 Update: Sparepart box
Ind. 6 Update
Ind. 7 Update Recommended lubricant brands
Ind. 8 Update on page 30, 295 →275 and document on page 75(PLE - 02/2011)
For better understanding and legibility, if this user manual is printed out, then duplex printing is
preferable.

PN-0706056 Ind. 8 3-80
THE ART OF WELDING
MU IV
Contents
1. Safety precautions ............................................................................................ 5
1. 1. Arc welding hazards........................................................................................... 5
1. 2. Meaning of the symbols......................................................................................5
1. 3. Recommendations ............................................................................................. 6
2. General information .......................................................................................... 9
2. 1. Reference documents......................................................................................... 9
2. 2. Applicable directives .......................................................................................... 9
3. General introduction.........................................................................................11
3. 1. Introduction.................................................................................................... 11
3. 2. Classication of machine .................................................................................. 11
3. 3. Environment and operating conditions ................................................................ 12
3. 4. Description of the equipment ............................................................................ 12
3. 5. Technical characteristics ................................................................................... 21
3. 6. Capacities....................................................................................................... 21
3. 7. Equipment compatibility ................................................................................... 22
3. 8. Dimensions..................................................................................................... 23
4. Installation .....................................................................................................26
4. 1. Handling ........................................................................................................ 26
4. 2. Installation on site........................................................................................... 26
4. 3. Handling ........................................................................................................ 26
4. 4. Bundle ........................................................................................................... 27
5. Use................................................................................................................28
5. 1. Precautions..................................................................................................... 28
5. 2. The electrode ................................................................................................. 29
5. 3. Wire sheaths................................................................................................... 33
5. 4. Ignition ring.................................................................................................... 35
5. 5. Built-in feeder................................................................................................. 36
5. 6. Adjusting the clamps........................................................................................ 39
5. 7. Adjusting the gas ow rate ............................................................................... 41
5. 8. Adjusting the oscillation ................................................................................... 41
5. 9. Positioning the welding head and preparing the weld............................................ 41
5. 10. Trial cycle ....................................................................................................... 41
5. 11. Performing a weld............................................................................................ 41
6. Maintenance and troubleshooting.......................................................................42
6. 1. Troubleshooting - diagnostics assistance ............................................................. 42
6. 2. Routine maintenance ....................................................................................... 43
6. 3. Recommended lubricant brands ......................................................................... 47
6. 4. Accessories box............................................................................................... 47
6. 5. Repairs and maintenance.................................................................................. 49
7. Wiring diagrams ..............................................................................................70
8. End of life – recycling of equipment....................................................................73
9. Returned material form ....................................................................................75

THE ART OF WELDING
MU IV
4-80 PN-0706056 Ind. 8

PN-0706056 Ind. 8 5-80
THE ART OF WELDING
MU IV
Safety precautions1.
Note: Protect yourself and others from injury - read and follow these instructions
Arc welding hazards1. 1.
The following symbols are used in the text to draw your attention and to identify risks and dangers.
When you see a symbol, consult the safety instructions in the Recommendations chapter hereafter.
Only qualied personnel should install, use, maintain and repair the system.
All persons not working on the equipment must remain well clear when it is in use.
Meaning of the symbols1. 2.
Risk of electric shocks Risk of severe injuries
caused by moving parts
Risk of fume or gas inhalation Risk of explosion
Risk of eye or skin burns
caused by radiation
Risks caused by exposure
to magnetic elds
Warning: hot parts – Risk of
burns Danger caused by noise
Risk of eye or skin burns
caused by ying sparks Read the instructions
Risk of overheating and re Eye protection is manda-
tory
Foot protection is mandatory Helmets are mandatory
Risk of falling
Read the following recommendations
and take any necessary measures to
avoid dangerous situations.

THE ART OF WELDING
MU IV
6-80 PN-0706056 Ind. 8
Recommendations1. 3.
Risk of electric shocks
Live parts include the electrode, the weld circuit,
the supply circuit and the internal circuits, the
ller wire and metal parts in contact with it, the
wire feeder unit and the wire feeding mechanism.
Any contact with these parts can cause an electric
shock if the installation is connected to the mains
supply.
Circumstances increasing the risk of electric
shocks: humid environments, working on conduct-
ing surfaces, poor earth connections, system in
poor condition, unsafe working conditions.
To prevent risks:
Avoid any contact with live wire•
spools.
Inspect water-cooled torches regularly•
to detect leakage. Pay attention to
condensation.
Never wind the cables around your•
body.
Make sure that the electrode is not live•
when changing it.
Before any maintenance, repair or•
pause, disconnect the equipment from
the mains supply.
Wear gloves, clothes, aprons and•
safety shoes that are dry and without
holes.
Carpets or other insulating materials•
must be used if the welder has to work
on metal surfaces or structures.
The equipment must be installed and•
earthed as specied in the operating
manual.
The current return cable must be xed •
correctly (clean surface, solid clamping
as close as possible to the weld area).
Cables that are damaged, worn,•
unsheathed, the wrong size or poorly
assembled must not be used and must
be replaced immediately.
The power supply must be properly•
earthed.
Use a separate cable if the workpiece•
must be earthed.
Appropriate connectors must be used.•
Pay attention to the off-load voltage that is
limited to 80 V efcient AC or 113 V DC (nec-
essary for the arc ignition). Maximum value
for plasma cutting power supplies: 500 V.
Risk of fume or gas inhala-
tion
During welding, fumes and gases are released
which are harmful to your health. Avoid inhaling
fumes.
Sources of fume and gas emissions: basic materi-
al, ller metal, coating (ux) by covered electrode,
shielding gas, solvents and materials covering the
workpiece.
To prevent risks:
Use breathing apparatus, such as lter •
masks, ventilated masks, air-supply
masks, disposable masks.
Avoid chlorinated solvents.•
Dry the workpieces thoroughly before•
welding.
Do not work alone!•
Trap fumes and gases at the source.•
Remove paint, oil and any other coat-•
ings from the surface.
Risk of eye or skin burns
caused by radiation
The radiation from the arc can cause eye and skin
burns.
Risk identication: exposure to intense visible and
invisible radiation from the arc (ultraviolet and
infrared). Radiation is reected by welding metals
such as aluminium or stainless steel. Flash burns,
sparks, stings caused by the tungsten electrode
tip.
To prevent risks:
Wear gloves or leather gauntlets to•
protect hands and forearms.
Wear an apron or gaiters to protect•
the legs, knees and feet.
Wear a mask (strapped to the head,•
hand-held or electronic) or goggles t-
ted with a suitable lter
Use protective curtains to protect staff•
working nearby.
Wear a scarf around your neck and close the collar
of your garment.

PN-0706056 Ind. 8 7-80
THE ART OF WELDING
MU IV
Warning: hot parts – Risk of
burns
Do not touch welded or torch-cut parts. When
handling hot workpieces, use suitable tools and/
or wear thick, heat-proof welding gloves to avoid
burns.
Welded parts must be allowed to cool down before
handling or further welding operations.
Risk of eye or skin burns
caused by ying sparks
Wear gloves or leather gauntlets to•
protect hands and forearms.
Wear an apron or gaiters to protect•
the legs, knees and feet.
Wear a mask (strapped to the head,•
hand-held or electronic) or goggles t-
ted with a suitable lter
Use protective curtains to protect staff•
working nearby.
Wear cotton or woollen clothes with•
long sleeves, free of stains of oil or
lubricant, avoid synthetic fabrics.
Wear a scarf around your neck and•
close the collar of your garment.
Wear safety boots for welders.•
Risk of overheating and re
Keep the power generator in good•
condition, especially the supply cables
and the current return cable.
Keep a minimum distance of 6 m•
between the welding equipment and
any greasy, inammable or dusty
substance.
Use protective curtains to protect staff•
working nearby.
Risk of explosion
These risks related to the use and handling of gas
cylinders and ying sparks.
Never use damaged gas cylinders.•
Stock the gas cylinders in a well-ven-•
tilated room, open to authorised staff
only.
The temperature must never exceed•
55 °C when storing and using gas
cylinders.
Keep clearly marked empty gas cylin-•
ders separate from full ones.
Protect gas cylinders against extreme•
temperatures (frost, sun, sparks,
etc.).
Inspect connections and hoses regu-•
larly.
Use protective curtains.•
Risk of severe injuries
caused by moving parts
Never place your hands near a fan or•
other moving parts.
Keep all safety devices operational and•
in safety mode.
Risks caused by exposure
to magnetic elds
The distance between the brain and the welding
circuit is a very important factor.
Never wind cables around your body•
or, even more importantly, over your
shoulders.
Pacemaker users must make them-•
selves known. Possible interference
requires special preventive measures
that must be taken with a doctor’s
agreement.
The operator must make
sure that no one is exposed
in the danger zone.

THE ART OF WELDING
MU IV
8-80 PN-0706056 Ind. 8

PN-0706056 Ind. 8 9-80
THE ART OF WELDING
MU IV
General information2.
Reference documents2. 1.
PN-0706043 Illustrated parts lists of the wire feeder
PN-0706044 User guide of the wire feeder
PN-0706046 Illustrated parts lists MU IV 28 welding head
PN-0706047 Illustrated parts lists MU IV 38 welding head
PN-0706048 Illustrated parts lists MU IV 64 welding head
PN-0706049 Illustrated parts lists MU IV 80 welding head
PN-0706050 Illustrated parts lists MU IV 104 welding head
PN-0706051 Illustrated parts lists MU IV 115 welding head
PN-0706052 Illustrated parts lists MU IV 128 welding head
PN-0706053 Illustrated parts lists MU IV 195 welding head
PN-0706054 Illustrated parts lists MU IV 245 welding head
PN-0706055 Illustrated parts lists MU IV 275 welding head
Applicable directives2. 2.
2006/42/CE ‘Machinery’ Directive
2004 /108 /CE Electromagnetic compatibility
2006/95 /CE Electrical equipment designed to be used within certain voltage limits

THE ART OF WELDING
MU IV
10-80 PN-0706056 Ind. 8

PN-0706056 Ind. 8 11-80
THE ART OF WELDING
MU IV
General introduction3.
Introduction3. 1.
The MU IV open welding heads are designed for butt joint welding of the following types:
Tube/tube.•
Tube/accessories (tee, elbow, ange, etc.).•
The TIG welding process is used with or without ller materials.
Some examples of applications:
The MU IV welding head range is used to weld tubes with an exterior diameter of between Ø8 mm and Ø275 mm.
It includes 10 head sizes with different welding capacities as shown in the following table and diagram:
These instructions do not deal with elements that are not supplied by Polysoude.
Classication of machine3. 2.
The machine complies with the requirements of the directives 2006/42/EC “Machines”, 2006/95/EC “Electrical
equipment designed for use within certain voltage limits” and 2004/108/EC “Electromagnetic compatibility”.

THE ART OF WELDING
MU IV
12-80 PN-0706056 Ind. 8
Environment and operating conditions3. 3.
This material is designed to function in the workshop in non-explosive atmospheres.
In the operational phase, the following conditions must be respected:
The ambient air temperature is between -10° and +40°C.
Relative humidity:
Up to 50% at 40°C.•
Up to 80% at 20°C.•
The ambient air must not contain unusual quantities of dust, acids, gases or corrosive substances. Emissions
due to welding are considered as normal.
Examples of unusual conditions of use:
Unusual corrosive fumes.•
Steam.•
Excessive oil vapour.•
Shaking or vibrations.•
Protect the air inlet and outlet when using the equipment.
Parts can be reheated up to 150°C
Max. inter-pass temperature of 200°C.
Description of the equipment3. 4.
This range of open welding heads is exible and adaptable.
Two welding plates:
Simple plate: the torch is adjusted manually.•
AVC/OSC plate: the torch is controlled by software that is integrated in the power generator.•
Two separate clamps:
A chuck clamp that clamps the entire diameter of the range using the adjusting knobs.•
An cooled shell clamp that is optimised for each weld diameter (one shell per diameter). Recom-•
mended for pre-heating.
Two different motors according to the selected means of clamping (see diagram 3-1).
Standard motor for chuck clamps.•
Motor for cooled shell clamps.•
The dimensions of the head can be adjusted using two types of engine outlet:
outlet parallel to the tube•
angle outlet•
Three types of gas lens, according to the diameter of the tubes to be welded.

PN-0706056 Ind. 8 13-80
THE ART OF WELDING
MU IV
Standard
motor
Motor for
cooled shell
clamps
Chuck clamps
Shell clamps
Tube outlet
Tube //
outlet
Tube outlet for
clutch
Tube // outlet
for clutch
Clutch
Drive
Plate
AVC/OSC
plate
Torch Gas lens Wire ad-
justment
Wire
sheath
Wire sheath
for built-in
feeder
Built-in
feeder
Wire option
Fig.3.1 - Possible combinations

THE ART OF WELDING
MU IV
14-80 PN-0706056 Ind. 8
3
2
1
5
6
MU IV3. 4. 1. weld head
Illustration of the subassemblies of the MU IV.
Motor (Fig.3.2 - 1).•
Coupling between the motor and the drive, called the “motor output” (Fig.3.2 - 2).•
Drive mechanism (Fig.3.2 - 3).•
Clamping device•
Clamps (Fig.3.2 - 4a)-
Shell (Fig.3.2 - 4b).-
Weld plate (Fig.3.2 - 5).•
Weld plate with AVC OSC (Fig.3.2 - 6).•
A built-in wire feeder (from MU 128 AVC/OSC only) (Fig.3.2 - 7).•
Wire feeder Polyl (Fig.3.2 - 8).•
The preceding assembly diagram shows the different possible combinations (Fig.3.1).
Fig.3.2 - Illustration of the subassemblies of the MU IV

PN-0706056 Ind. 8 15-80
THE ART OF WELDING
MU IV
4a
4b
7
8

THE ART OF WELDING
MU IV
16-80 PN-0706056 Ind. 8
1
2
3
4
Motorisation:
The motor is made up of a DC reducer motor
(Fig.3.3 - 1) delivering a range of welding speeds
between 50 and 150 mm/min.
The ratio of the reducer is R=1/400.
An encoder (Fig.3.3 - 2) attached to the motor in-
forms the Polysoude welding generator of the actual
position of the torch and is used to control the weld-
ing sequence (control of the sector starts and stops).
This encoder is also used to adjust the advance speed
of the torch to a precision of about 1%.
Two motor covers are available:
One cover if the head is assembled with a•
chuck or shell clamp (Fig.3.3 - 3).
Another cover if the head is assembled•
with a cooled clamp (Fig.3.3 - 4).
Fig.3.3 - Motors

PN-0706056 Ind. 8 17-80
THE ART OF WELDING
MU IV
1
3
2
4
Couplings:
A number of motor outputs are available. They are used to couple the motor to the drive. A clutch is installed
on large heads (MU IV 195 to 245) to facilitate the repositioning of the head after a weld cycle.
This includes:
An outlet parallel to the tube.•
An angle output (perpendicular to the tube).•
For MU IV 195 to 275:
A clutch.•
An outlet parallel to the tube for the clutch.•
An angle output for the clutch (perpendicular to the tube).•
An outlet parallel to the tube (Fig.3.4 - 1).
An special outlet parallel to the tube for MU IV 195 to 275 (Fig.3.4 - 2) with a clutch system.
An outlet perpendicular to the tube (Fig.3.4 - 3).
An special outlet perpendicular to the tube for MU IV 195 to 275 (Fig.3.4 - 4) with a clutch system.
Fig.3.4 - Couplings

THE ART OF WELDING
MU IV
18-80 PN-0706056 Ind. 8
1
2
4
3
Clamping devices:
Two systems are available:
The chuck clamp:
The chuck clamp is made up of two synchronized arms (Fig.3.5 - 2), whose prole can be manually adjusted
to clamp and centre the assembly on the part to be welded. A single control lever (Fig.3.5 - 1) is used to
clamp and unclamp.
The shell clamp:
The shell clamp is made up of a spring clip type mechanism that controls a clamping arm (Fig.3.5 - 3) tted
with an adjusting screw (Fig.3.5 - 4) according to the diameter.
The mechanism receives a “parent” shell that is tted with intermediate shells adapted to the diameters of the
tubes, according to the capacity of the head.
As an option, the housing of this mechanism can be liquid-cooled in order to thermally insulate the head, in
particular when welding pre-heated tubes.
Fig.3.5 - Clamps

PN-0706056 Ind. 8 19-80
THE ART OF WELDING
MU IV
1
3
2
4
Welding plates:
Two systems are available:
Simple plate (Fig.3.6 - 1-2):
The simple plate is used to hold and adjust the torch with regard to the welding plane. The simple plate is
manually adjusted.
This plate is made up of:
A plate that is directly attached to the drive crown gear.•
An insulating torch support.•
An arm with a radial tube sensor used for the manual transverse adjustment of the torch in rela-•
tion to the welding plane.
A device to adjust the height that allows for an axial offset of the torch in relation to the welding•
plane (only on plates MU IV 195 to 245).
AVC/OSC plate (Fig.3.6 - 3-4):
Heads equipped with an AVC/OSC plate can only be used with generators with the corresponding functions.
The AVC/OSC plate is tted with two motor-driven slides controlled by the generator.
This plate includes more parts than the simple plate:
The AVC system that moves the torch in the radial direction.•
The OSC (oscillation) assembly, that moves the torch perpendicularly to the weld plane.•
The generator is used to control these two axes during the weld cycle.
The AVC shaft is used to check and adjust the tension of the arc and to keep it at the programmed value.
The OSC shaft is used to adjust the axial position of the electrode. The oscillation system can be programmed
to scan the weld from right to left for wide weld beads.
Fig.3.6 - Plates

THE ART OF WELDING
MU IV
20-80 PN-0706056 Ind. 8
132
Torch:
The torch is attached to the plate’s torch support. It is
liquid cooled.
It is connected to the generator by:
A exible multi-duct (Polysoude patent) •
for power, gas and coolant supply.
A 7-meter harness tted with quick-t •
connections.
The length of the multi-duct depends on the reel di-
ameter on the welding head:
2.2 m for MU IV 28 to 104.•
3.2m for MU IV 115 to 295.•
Gas lenses:
Three types of gas lens, according to the diameter
of the tubes to be welded:
GM type (Fig.3.8 - 1).•
P type (Fig.3.8 - 2).•
N type (Fig.3.8 - 3).•
Wire option:
This device feeds the ller wire to the weld.
There are two types of feeder:
The exterior feeder can be used on the•
entire range (Fig.3.9).
The built-in feeder can only be used from•
MU IV 128, with AVC /OSC plate to MU IV
275 (Fig.3.10).
Fig.3.7 - Torch
Fig.3.9 - Exterior feeder assembly
Fig.3.8 - Gas lenses
Fig.3.10 - Built-in feeder assembly