17
10.0 PROBLEMS - CAUSES
10.1 Possible cutting defects
10.2 Possible electrical failures
See also chapter 4.1 for problems with alarm code.
If you have any doubts or problems, do not hesitate to con-
sult your nearest technical service centre.
11.0 NECESSARY ROUTINE MAINTENANCE
Prevent metal powder from accumulating near the aeration fins
and over them.
Disconnect the power supply before every opera-
tion!
Carry out the following periodic controls on the
power source:
* Clean the power source inside by means of low-
pressure compressed air and soft bristel brushes.
* Check the electric connections and all the connec-
tion cables.
For the maintenance or replacement of torch
componente and/or earth cables:
* Disconnect the power supply before every operation.
* Check the temperature of the componente and make
sure that they are not overheated.
* Always use gloves in compliance with the safety stan-
dards.
* Use suitable spanners and tools.
* For torch maintenance, keep carefully to the directions
shown under instructions for use of the torch enclosed
with this manual.
NOTE: Failure to perform said maintenance will invalidate all
warranties and exempt the manufacturer from all liability.
12.0 THEORETICAL OUTLINE OF PLASMA
CUTTING
A gas assumes the plasma state when it is brought to an extre-
mely high temperature and ionizes wholly or partly, thus beco-
ming electrically conductive.
Although the plasma exists in every electric arc, by the term
"plasma arc" we refer specifically to a torch for welding or cut-
ting that uses an electric arc, made to pass through the constric-
ting neck of a suitable nozzle, to heat a gas coming out of this,
so as to take it to the plasma state.
Fig. 7 Manual plasma cutting plant
FAULT
Insufficient penetration
The cutting arc goes out
Substantial burr formation
Nozzle overheating
CAUSE
- Cutting speed too high
- Current set too low
- Earth clamp with inefficient
contact
- Thickness of piece excessive
- Electrode, nozzle or diffuser
worn
- Air pressure too high
- Cutting speed too low
- Insufficient air flow
- Defective pressure switch
- Supply voltage too low
- Inadequate air pressure
- Cutting speed too low
- Nozzle eroded
- Electrode eroded
- Insufficient air quantity
FAULT
Apparatus fails to come on
(Green LED L1 off)
Pilot arc fails to ignite
(with green LED L1 on)
Pilot arc fails to ignite
(with green LED L1 and red
LED L2 on)
Fails to transfer from pilot arc
to cutting arc
Lack of power output
CAUSE
- Incorrect mains supply
- Fuses interrupted
- Break in the contacts of the
torch button (check the con-
nection of the torch attach-
ment is working after having
cut off the power supply)
- Torch parts subject to wear
out of action
- Air pressure too high
- Possible problems in control
circuits
- Possible problems in control
circuits
- Arc sensors faulty (board
15.14.084)
- Protective devices triggered
(see chapter on "Functions of
controls")
- Possible problems in control
circuits