Miller STi 270, Руководство пользователя

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OM-263 706 Page 17
5-4. Process Control
1 Process Control
Use control to select Stick, or the
TIG Lift Arc process.
Stick (SMAW) - This is a DCEP (di-
rect current electrode positive)
process (see Section 5-6). Make
connections according to Section
4-5.
TIG Lift-Arc
t
- This is a DCEN (di-
rect current electrode negative)
process in which the electrode
must come in contact with the work
piece to initiate an arc (see Section
5-5). Make connections according
to Section 4-4.
1
5-5. Lift-Arc Start Procedure
Lift-Arc Start
With Lift-Arc
t
selected, start arc
as follows:
1 TIG Electrode
2 Workpiece
Turn gas on. Touch tungsten elec-
trode to workpiece at weld start
point. Hold electrode to work-
piece for 1-2 seconds, and slowly
lift electrode. Arc is formed 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.
Application:
Lift-Arc is used for the DCEN
GTAW process when HF Start
method is not permitted, or to re-
place the scratch method.
1
1 − 2
Seconds
“Touch”
Do NOT Strike Like A Match!
2
Lift-Arc Start Method