WELDKAR WK MIG 3140, Instruction Manual

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4. MAINTENANCE
ANY MAINTENANCE OPERATION MUST BE
CARRIED OUT BY QUALIFIED PERSONNEL.
4.1 MAINTENANCE OF THE WELDING
INVERTER
In the case of maintenance inside the machine, make
sure that the switch (4) is in position “0” and that
the power cord is disconnected from the mains. It is
also necessary to periodically clean the interior of
the machine from the accumulated metal dust, using
compressed air.
4.2 PRECAUTIONS AFTER REPAIRS
After making repairs, take care to organize the wiring
so that there is secure insulation between the primary
and secondary sides of the machine. Do not allow the
wires to come into contact with moving parts or those
that heat up during operation. Reassemble all clamps
as they were on the original machine, to prevent a
connection from occurring between the primary and
secondary circuits should a wire accidentally break or
be disconnected. Also mount the screws with geared
washers as on the original machine.
Fault Cause
Feed roller driven by motor in the
cabinet slipped.
Wire spool brake is too tight.
Wire spool unwinded and tangled. Wire spool brake is too loose.
Worn or incorrect feed roller size Use a feed roller matched to the size you are welding.
Replace feed roller if worn.
Wire rubbed against the mis-aligned
guides and reduced wire feedability.
Mis-alignment of inlet/outlet guides.
Liner blocked with swarf. Increased amounts of swarf are produced by the wire passing through the feed
roller when excessive pressure is applied to the pressure roller adjuster.
Swarf can also be produced by the wire passing through an incorrect feed
roller groove shape or size.
Swarf is fed into the conduit liner where it accumulates thus reducing wire
feedability.
Incorrect or worn contact tip The contact tip transfers the weld current tot he electrode wire. If the hole
in the contact tip is too large then arcing may occur inside the contact tip
resulting in the wire jamming in the contact tip.
When using soft wire such as aluminium it may become jammed in the contact
tip due to expansion of the wire when heated.
Poor work lead contact to work piece. If the work lead has a poor electrical contact to the work piece then the
connection point will heat up and result in a reduction of power at the arc.
Bent liner. This will cause friction between the wire and the liner thus reducing wire
feedability.
4.3 TROUBLESHOOTING & SERVICE
Problems with inconsistent wire feed:
Wire feeding problems can be reduced by checking the following points: