Tweco SL100 - Manual (Page 16)

INTRODUCTION 2-4 Manual 0-2962
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. Capacitive Discharge
Because direct current (DC) alone is not sufficient to
strike and maintain the pilot arc, capacitive discharge
is also used. The high voltage jumps between the tip
and electrode with the DC following.
NOTE
Not all power supplies have this feature.
E. Main Cutting Arc
DC power is also used for the main cutting arc. The
negative output is connected to the torch electrode
through the torch lead. The positive output is con-
nected to the workpiece via the work cable and to the
torch through a pilot wire.
F. 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.
A-02997
Torch Trigger
PIP Switch Shield Cup
To Control
Cable Wiring
Torch Switch
Parts - In - Place Circuit Diagram for Hand Torch
A-03504
PIP Switch Shield Cup
To Control
Cable Wiring
Parts - In - Place Circuit Diagram for Machine Torch