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Appendix B
•
From time T
(Background Current) 100 Amps that maintains an arc to form a weld bead.
•
From time T
(Ball Time)
•
From time T
(Pinch)
•
Time T
(Fuse Separation)
•
From time T
(Plasma Boost)
•
From time T
(Plasma)
STT WAVE SHAPING PRINCIPLES
FIGURE B-2. WELD DROPLET TRANSFER.
BACKGROUND AMPS
T
T
0
1
to T
:
Background current is a steady-state current level, between 50 and
0
1
to T
:
An arc voltage detector indicates that the arc is shorted; background
1
2
current is reduced for approximately 0.75 milliseconds.
to T
:
High current is applied to speed the transfer of molten metal to the
2
3
weld puddle. A dV/dt calculation indicates when fuse separation is
about to occur; current is reduced to 50 Amps.
:
Fuse separation occurs at low current. Time T
4
voltage, and not indicated on the amperage waveform.
to T
:
A period of high arc current that melts the electrode back.
5
6
to T
:
Arc current is reduced from Peak Amps to the Background current
6
7
level.
WAVE DESIGNER
PEAK
AMPS
T
T
T
5
2
3
B-3
TAILOUT
T
T
7
6
27850060
is a function of
4
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