Telwin Plasma 54 Manuel D'utilisation page 9

7. MAINTENANCE
WARNING! BEFORE
OPERATIONS, MAKE SURE THAT THE PLASMA CUTTING SYSTEM
IS SWITCHED OFF AND DISCONNECTED FROM THE MAIN POWER
SUPPLY.
ROUTINE MAINTENANCE
ROUTINE MAINTENANCE CAN BE CARRIED OUT BY THE OPERATOR.
TORCH (FIG. N)
Depending on the amount of use, make regular checks on the wear of the
parts of the torch concerned with the plasma arc and proceed likewise if
cutting defects are noted.
1- Spacer.
Change it if it is so deformed or covered with slag that it is impossible
to maintain the correct position of the torch (distance and
perpendicularity).
2- Nozzle holder.
Unscrew it manually from the head of the torch. Clean it carefully or
change it if it is damaged (burnt, deformed or cracked). Make sure the
top metal section is intact (torch safety rocker).
3- Nozzle.
Check for wear on the plasma arch passage hole and on the inside and
outside surfaces. If the hole is larger than the original diameter or if it
is deformed, change the nozzle. If the surfaces are particularly oxidized
clean them with very fine abrasive paper.
4- Air distribution ring.
Make sure there are no burns or cracks and that the air passage holes
are not blocked. If damaged, change the ring immediately.
5- Electrode.
Change the electrode when the depth of the crater formed on the
emitter surface is approx. 1.5 mm (FIG. O).
6- Torch body, handgrip and cable.
These components do not normally need any particular maintenance
apart from regular inspection and careful cleaning without using any
kind of solvent. If the insulation is damaged, with breakages, cracks or
burns etc., or if the electric leads are loose, the torch may not be used
because it does not satisfy safety requirements.
In this case repairs (extraordinary maintenance) cannot be done on the
spot and the torch must be sent to an authorised service centre, which
will be able to carry out the special tests needed after the repair has
been done.
In order to keep the torch and cable in good working order, take the
following precautions:
- do not allow the torch and cable to come into contact with hot or
red-hot parts.
- do not pull the cable hard.
- do not pass the cable over pointed or sharp edges or over abrasive
surfaces.
- wind the cable into regular loops if it is longer than needed.
- do not pass over the cable with any vehicle and do not stand on it.
Warning.
- Before carrying out any work on the torch leave it to cool for at least the
complete "post air" time
- Except in special cases, we recommend changing the electrode and
nozzle at the same time.
- Assemble the torch components in the correct order (the reverse of the
order for dismantling).
- Make sure that the distributor ring is fitted the right way round.
- When re-assembling the nozzle holder, screw it down manually, forcing
it slightly.
- Never ever fit the nozzle holder before you assemble the electrode,
distributor ring and nozzle.
- Do not keep the pilot arc struck in air for no reason as this will increase
electrode, diffuser and nozzle wear.
- Do not tighten the electrode too much as this could damage the torch.
- Prompt, correct inspection procedures for the consumable parts of the
torch are essential for safe, correct operation of the cutting system.
- If the insulation is damaged, with breakages, cracks or burns etc., or
if the electric leads are loose, the torch may not be used because it
does not satisfy safety requirements. In this case repairs (extraordinary
maintenance) cannot be done on the spot and the torch must be sent
to an authorised service centre, which will be able to carry out the
special tests needed after the repair has been done.
CARRYING OUT MAINTENANCE
Compressed air filter
- The filter is designed for automatic condensation drainage whenever it
is disconnected from the compressed air line.
- Inspect the filter regularly; if there is water in the glass it can be drained
off manually by pushing the drain connector upwards.
- If the filter cartridge is especially dirty it must be changed in order to
prevent an excessive pressure loss.
EXTRAORDINARY MAINTENANCE
EXTRAORDINARY MAINTENANCE MUST BE CARRIED OUT ONLY AND
EXCLUSIVELY BY AUTHORISED EXPERT OR SKILLED ELECTRICAL-
MECHANICAL TECHNICIANS.
WARNING! BEFORE REMOVING THE MACHINE PANELS AND
WORKING INSIDE IT MAKE SURE THAT IT HAS BEEN SWITCHED OFF
AND DISCONNECTED FROM THE MAIN POWER SUPPLY.
If checks are carried out inside the machine while it is live, this may
cause serious electric shock due to direct contact with live parts.
- Inspect the inside of the machine regularly, with a frequency depending
on the amount of use and dust in the environment, and remove
dust that has deposited on the transformer, rectifier, inductance and
resistors, using a jet of dry compressed air (max 10 bar).
- Do not direct the jet of compressed air onto the electronic boards;
these can be cleaned with a very soft brush or suitable solvents.
- Take the opportunity to make sure the electrical connections are tight
and there is no damage to the wiring insulation.
- Make sure the compressed air circuit hoses and connections are intact
and leak-free.
- When these operations have been completed, re-assemble the panels
on the machine and tighten the fastening screws right down.
- Never ever carry out cutting operations with the machine open.
- After having carried out maintenance or repairs, restore the connections
and wiring as they were before, making sure they do not come into
contact with moving parts or parts that can reach high temperatures.
Tie all the wires as they were before, being careful to keep the high
voltage connections of the primary transformer separate from the low
voltage ones of the secondary transformer.
Use all the original washers and screws when closing the casing.
8. TROUBLESHOOTING
IN THE CASE OF UNSATISFACTORY OPERATION, AND BEFORE CARRYING
OUT MORE SYSTEMATIC TESTS OR CONTACTING YOUR SERVICING CENTRE
CARRY OUT THE FOLLOWING CHECKS:
- Check whether the yellow LED is ON, indicating triggering of the
thermal cutout, over- or under-voltage or shorting.
- Make sure that the nominal duty cycle has been respected; if the
thermal cutout triggers, wait until the machine cools down naturally
then make sure the fan is working properly.
- Check the power supply voltage: if it is too high or too low the machine
will not work.
- Make sure there is no shorting at machine output: if there is shorting
remove the cause.
- Make sure the cutting circuit connections are correct, in particular
that the earth cable clamp is actually connected to the piece with no
insulating material in between (e.g. paint).
MOST COMMONLY OCCURRING CUTTING DEFECTS
During cutting operations it is possible that defects occur, which are
not normally caused by operating faults in the system but by other
operational matters such as:
a- Insufficient penetration or excessive slag formation:
- Cutting rate too high.
- Over-inclined torch.
- Piece too thick or cutting current too low.
- In appropriate compressed air pressure-flow.
- Worn electrode and torch nozzle.
- Inappropriate nozzle-holder tip.
b- Arc transfer failure:
- Worn electrode.
- Poor contact of the return cable terminal clamp.
c- Interrupted cutting arc:
- Cutting rate too low.
- Torch-piece distance too high.
- Worn electrode.
- A safeguard has triggered.
d- Inclined cut (not perpendicular):
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