Lift-Arc Tig Procedure; Optional Low Open Circuit Voltage (Ocv) Welding Modes - Miller XMT 425 CC/CV Auto-Line Mode D'emploi

5-4. Lift-Arc TIG Procedure

5-5.

Optional Low Open Circuit Voltage (OCV) Welding Modes

OM-234 196 Page 20
1
1 − 2
"Touch"
Seconds
Do NOT Strike Like A Match!
2
Low OCV Operation
The unit can be optionally configured for low open cir-
cuit voltage (OCV) operation in Stick and Scratch
Start TIG modes. When the unit is configured for low
OCV operation only a low sensing voltage (approxi-
mately 15 VDC) is present between the electrode and
the workpiece prior to the electrode touching the work-
piece. Consult a Factory Authorized Service Agent for
information regarding how to configure the unit for low
OCV welding operation.
With Process Switch in the Lift-Arc
TIG position, start an arc as follows:
1 TIG Electrode
2 Workpiece
Touch tungsten electrode to work-
piece at weld start point, hold
electrode to workpiece for 1-2
seconds, and slowly lift electrode.
An arc will form when electrode is
lifted.
Normal open-circuit voltage is not
present before tungsten electrode
touches workpiece; only a low
sensing voltage is present between
electrode and workpiece. The
solid-state output contactor does
not energize until after electrode is
touching workpiece. This allows
electrode to touch workpiece with-
out overheating, sticking, or getting
contaminated.
Ref. S-156 279