Migatronic NAVIGATOR 2500 Manuel D'instruction page 21

100%
However, this balance is based on the current intensity
of the positive period proportional to the current
intensity of the negative period. A reduction of the
positive refinement current may have the effect that
dwell time of the tungsten electrode improves.
TIG-DC
It is also possible to weld in DC TIG with unalloyed
tungsten electrodes (green marking). Current is set to
AC and both AC-t-balance and AC-I-balance are set at
100 per cent. The machine will then establish the pilot
arc by using the preheating function. After finishing the
preheating period the welding current will be returned
to negative polarity.
Fixed functions
The functions below are fixed and cannot be
connected and disconnected from the display:
Anti-freeze
The anti-freeze-function is always on. During MMA
and TIG welding the electrode sometimes sticks onto
the workpiece. The machine will register that the
electrode has stuck onto the workpiece, and will then
reduce the welding current so that the area of the
workpiece which has melted will harden, making it
possible to break off the electrode. Welding can then
continue in the usual way.
Torch cooling
The machine will automatically start cooling when
establishing the arc if the machine has been mounted
with a cooling module and a Migatronic water-cooled
torch. Cooling continues until 2½ min. after the welding
process has stopped.
Ignition of the arc in AC/TIG welding
It can be advantage to use reduced start current (e.g.
25%) and slope up (e.g. 0.1 sec.) during ignition of the
arc in AC/TIG welding as wolfram from the electrode
pin can be avoided on the work piece. This method is
especially recommendable during welding with large
currents.
150% 50%
FAULT IDENTIFICATION
Overheating error
Welding is interrupted due to overheating if the
machine is used
mentioned in chapter "Technical Data". The machine
must remain turned on and connected to the mains
supply as the fan continues until the machine has
been sufficiently cooled. Thereafter, the machine is
automatically switched in.
An overheating error is more oftenly seen if the
machine is used in surroundings with temperatures
o
above 40 C. It is not recommendable to place the
machine in direct sun light as this increases the
possibility of an overheating of the machine.
Mains error
The mains error arises if the mains voltage is
too high or low.
Please make sure that the mains plug is correctly
mounted and that all fuses are intact. Moreover,
please control that the mains voltage does not exceed
the technical specifications and that there are no short-
term voltage drops or voltage peaks.
Torch cooling error
This error can be seen by the text "Etc" in the machine
display. Turn off the machine if the cooling water does
not flow in the water-cooled torch. Make sure that all
hoses have a
"maintenance". Turn on the machine again when a
free passage has been established. Welding can then
be continued.
Other errors shown in the display
If other errors arise than those decribed above, please
contact the Migatronic service department.
21
beyound the specifications
free passage, see chapter