Lincoln Electric IM649 Wave Designer - Manual (Page 68)

B.6 SECONDARY STT WAVEFORM COMPONENTS
NOTE: The Invertec STT power source circuitry automatically establishes proper values for most
primary and secondary waveform components. The values can be adjusted, but should
not be set far from their automatically set values.
B.6.1 PINCH START
The pinch start is the amperage setting that begins the ramp up to the maximum pinch current.
Pinch start current must exceed background current.
B.6.2 PINCH/PEAK
Pinch/Peak is the ratio of maximum pinch current to peak current. This parameter is used to
establish the desired maximum pinch current value.
B.6.3 PEAK TIME
Peak time is the duration of the plasma boost period (peak amps) in milliseconds. The duration of
peak time is typically set from 1 to 2 milliseconds. Longer peak times may cause weld spatter.
B.6.4 dV/dt DETECT
The dV/dt detect setting determines at what point in the necking down process pinch current will
be discontinued.
B-14 Appendix B STT WAVE SHAPING PRINCIPLES
WAVE DESIGNER