Tweco A80 CutMaster - Manual (Page 21)

CUTMASTER A80
Manual 0-4985 INTRODUCTION 2T-3
B. Gas Distribution
The single gas used is internally split into plasma and
secondary gases.
The plasma gas flows into the torch through the negative
lead, through the starter cartridge, around the electrode,
and out through the tip orifice.
The secondary gas flows down around the outside of the
torch starter cartridge, and out between the tip and shield
cup around the plasma arc.
C. Pilot Arc
When the torch is started a pilot arc is established between
the electrode and cutting tip. This pilot arc creates a path
for the main arc to transfer to the work.
D. Main Cutting Arc
DC power is also used for the main cutting arc. The nega-
tive output is connected to the torch electrode through
the torch lead. The positive output is connected to the
workpiece via the work cable and to the torch through a
pilot wire.
E. Parts - In - Place (PIP)
The torch includes a 'Parts - In - Place' (PIP) circuit. When
the shield cup is properly installed, it closes a switch. The
torch will not operate if this switch is open.
Parts - In - Place Circuit Diagram for Machine Torch
Parts - In - Place Circuit Diagram for Hand Torch