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6. MAINTENANCE
6.1.
Wire feed unit
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
welding. Clean the rollers weekly, especially the feed roller groove, removing all dust deposits.
6.2.
Cleaning / Changing feed roller
IMPORTANT: The feed roller groove must correspond to the wire size.
There are two grooves on the feed roller, 0.6mm and 0.8mm, (optional 1.0mm roller available Part No: 120/722629). Always use the groove on the outside
of the roller (the groove nearest to you). To remove the feed roller, undo the two screws and remove the plastic cover (fig.4b).
Clean the roller or change if damaged, refit with the groove corresponding to the wire in use on the outside and then replace the plastic cover.
6.3.
Torch
Protect the torch cable assembly from mechanical wear. Clean the liner from the machine forwards by using compressed air. If the liner is clogged it must
be replaced.
6.4.
Contact Tip
To remove/replace tip follow steps in 3.5.6./3.5.9. very carefully.
The contact tip is a consumable item and must be replaced when the hole becomes enlarged or oval. The contact tip MUST be kept free from spatter to ensure
an unimpeded flow of gas.
6.5.
Gas Cup
To remove/replace cup follow steps in 3.5.6./3.5.9. very carefully.
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 either the fuse blowing on the printed circuit card or expensive machine repairs. To keep the contact tip free from spatter, we recommend the use of Sealey
anti-spatter spray (MIG/722307) and a nozzle cleaning tool (AK107) available from your Sealey Dealer.
6.6.
Replacing the liner
Wind the wire back on to the spool and secure it. Unscrew the torch from the machine and undo the brass nut. The liner should now be visible. Pull it out and
replace with a new one. Note: If using 1.0mm wire the optional liner (120/722689) will be required.
6.7.
Changing gears
An inexperienced welder can allow spatter to build up in the tip and shroud. In severe cases this can block the wire feed causing gear stripping in the drive
motor. To check if the gears are worn, depress the button on the torch with the set switched on. If the gears are worn, a grating sound will be heard coming
from the wire feed motor and you may also observe the feed roller vibrating instead of rotating. Should this be the case, open the gearbox, remove the worn
or damaged gears and replace with new ones.
7. ELECTROMAGNETIC COMPATIBILITY
7.1.
THIS EqUIPMENT IS IN CONFORMITY WITH THE EUROPEAN STANDARD ON THE ELECTROMAGNETIC COMPATIBILITY OF ARC WELDING
EqUIPMENT AND SIMILAR PROCESSES (e.g. ARC AND PLASMA CUTTING).
7.2.
Protection against interference. (E.M.C.) The emission limits in this standard may not, however, provide full protection against interference to radio and
television reception when the equipment is used closer than 30m to the receiving antenna. In special cases, when highly susceptible apparatus is being
used in close proximity, additional mitigation measures may have to be employed in order to reduce the electromagnetic emissions. At the same time there
could occur some potential difficulties in having electromagnetic compatibility in a non-industrial environment (e.g. in residential areas). Therefore it is most
important that the equipment is used and installed according to the following instructions.
7.3.
Installation and use. The user is responsible for installing and using the equipment according to these instructions. If electromagnetic disturbances are
detected, then it shall be the responsibility of the user of the equipment to resolve the situation with the technical assistance of the supplier. In some cases
this remedial action may be as simple as earthing the circuit (see Note). In other cases it could involve constructing an electromagnetic screen, enclosing
the welding power source and the work, complete with associated input filters. In all cases the electromagnetic disturbances shall be reduced to the point
where they are no longer troublesome.
Note: The welding/cutting circuit may or may not be earthed for safety reasons. Changing the earthing arrangements should only be authorised by a
person who is competent to assess whether the changes will increase the risk of injury, e.g. by allowing parallel welding/cutting circuit return paths which
may damage the earth circuits of other equipment. Further guidance is given in IEC 974-13 'Arc Welding Equipment - Installation and Use'.
7.4.
Assessment of area. Before installing the equipment the user shall make an assessment of potential electromechanical problems in the surrounding area.
The size of the surrounding area to be considered will depend on the structure of the building and other activities that are taking place. The surrounding
area may extend beyond the boundaries of the premises.
The following shall be taken into account:
a) Other supply cables, control cables, signalling and telephone cables, above, below and adjacent to the welding equipment.
b) Radio and television transmitters and receivers.
c) Computer and other control equipment.
d) Safety critical equipment, e.g. security monitoring of industrial equipment.
e) The health of people in the vicinity, e.g. persons fitted with a pacemaker or hearing aid.
f) Equipment used for calibration or measurement.
g) The immunity of other equipment in the environment. The user shall ensure that other equipment being used in the environment is compatible. This
may require additional protective measures.
h) The time of day that welding and other activities are to be carried out.
7.5.
Mains supply. The equipment should be connected to the mains supply according to these instructions. If interference occurs, it may be necessary to take
additional precautions such as filtering of the mains supply. Consideration should also be given to shielding the supply cable of permanently installed
equipment in metallic conduit or equivalent. This shielding should be connected to the power source so that good electrical contact is maintained between
the conduit and the welding power source enclosure.
7.6.
Maintenance of the equipment. The equipment should be routinely maintained according to these instructions. All access and service covers should be
closed and properly fastened when the welding equipment is in operation. The welding equipment should not be modified in any way except for those
changes and adjustments covered in these instructions. In particular, the spark gaps of any arc striking and stabilising devices should be adjusted and
maintained according to the instructions.
7.7.
Cables. The welding/cutting cables should be kept as short as possible and should be positioned close together, running at or close to the floor level.
7.8.
Equipotential bonding. Bonding of all metallic components in the welding/cutting installation and adjacent to it should be considered. However, metallic
components bonded to the workpiece will increase the risk that the operator could receive a shock by touching these metallic components and the
electrode at the same time. The operator should be insulated from all such bonded metallic components.
7.9.
Earthing of the workpiece. Where the workpiece is not bonded to earth for electrical safety, nor connected to earth because of its size and position, e.g.
ship's hull or building steelwork, a connection bonding the workpiece to earth may reduce emissions in some, but not all instances. Care should be taken to
prevent the earthing of the workpiece increasing the risk of injury to others or damage to other electrical equipment. Where necessary, the connection of
the workpiece to earth should be made by a direct connection to the workpiece, but in some countries where direct connection is not permitted, the bonding
should be achieved by a suitable capacitance, selected according to national regulations.
7.10. Screening and shielding. Selective screening and shielding of other cables and equipment in the surrounding area may alleviate problems of interference.
Screening of the entire welding/cutting installation may be considered for special applications.
Supermig250
Issue No: 1 - 03/03/09
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