Tweco PAK 15XC - Manual (Page 18)

INTRODUCTION & DESCRIPTION 14 Manual 0-2251
2.5 THEORY OF OPERATION
Figure 2-D Theory of Operation
Plasma Arc Cutting and
Gouging
Plasma is a gas which is heated to an extremely high
temperature and ionized so that it becomes electrically
conductive. The plasma arc cutting process uses this
plasma to transfer an electric arc to a workpiece. The
metal to be cut is melted by the intense heat of the arc and
then blown away. The Merlin PAK 15XC is a high per-
formance plasma cutting system designed to cut most
metals up to two inches thick.
With a simple change of torch parts, the system can also be
used for plasma arc gouging. Plasma arc gouging is used
to remove material to a controlled depth and width.
The torch uses a cool plasma gas such as compressed air,
nitrogen, argon/hydrogen, or oxygen. The plasma gas
flows into the torch through the plasma torch lead and is
channelled into Zone A (Figure 2-D), where a pilot arc
between the torch electrode and tip heats and ionizes the
gas. The main cutting arc transfers to the workpiece
through the column of plasma gas as it flows out through
the torch tip orifice. Plasma Gas Flow
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A-00900
Power Supply
Workpiece
Coolant
Plasma Gas
Secondary Gas
Zone A
Zone B
Zone D
Zone C
(-)
(+)