Tweco 40mm Cutmaster - Manual (Page 20)

CUTMASTER 40mm
INTRODUCTION 2T-2 Manual 0-5084
F. Torch Ratings
Manual Torch Ratings
Ambient
Temperature
104° F
40° C
Duty Cycle 100% @ 120 Amps @ 400 scfh
Maximum Current 120 Amps
Voltage (V
peak
) 500V
Arc Striking Voltage 7kV
Mechanized Torch Ratings
Ambient
Temperature
104° F
40° C
Duty Cycle 100% @ 120 Amps @ 400 scfh
Maximum Current 120 Amps
Voltage (V
peak
) 500V
Arc Striking Voltage 7kV
G. Gas Requirements
Manual and Mechanized Torch Gas
Specifications
Gas (Plasma and Secondary) Compressed Air
Operating Pressure
Refer to NOTE
60 - 95 psi
4.1 - 6.5 bar
Maximum Input Pressure 125 psi / 8.6 bar
Gas Flow (Cutting and
Gouging)
300 - 500 scfh
142 - 235 lpm
!
WARNING
This torch is not to be used with oxygen (O
2
).
NOTE
Operating pressure varies with torch model, op-
erating amperage, and torch leads length. Refer
to gas pressure settings charts for each model.
H. Direct Contact Hazard
For standoff tip the recommended standoff is 3/16
inches / 4.7 mm.
2T.04 Options And Accessories
For options and accessories, see section 6.
2T.05 Introduction to Plasma
A. Plasma Gas Flow
Plasma is a gas which has been heated to an
extremely high temperature and ionized so that it
becomes electrically conductive. The plasma arc
cutting and gouging processes use this plasma to
transfer an electrical arc to the workpiece. The
metal to be cut or removed is melted by the heat
of the arc and then blown away.
While the goal of plasma arc cutting is separa-
tion of the material, plasma arc gouging is used to
remove metals to a controlled depth and width.
In a Plasma Cutting Torch a cool gas enters Zone
B, where a pilot arc between the electrode and
the torch tip heats and ionizes the gas. The main
cutting arc then transfers to the workpiece through
the column of plasma gas in Zone C.
A-00002
Workpiece
Power
Supply
+
_
C
B
A
Typical Torch Head Detail
By forcing the plasma gas and electric arc through
a small orifice, the torch delivers a high concen-
tration of heat to a small area. The stiff, constrict-
ed plasma arc is shown in Zone C. Direct current
(DC) straight polarity is used for plasma cutting,
as shown in the illustration.
Zone A channels a secondary gas that cools the
torch. This gas also assists the high velocity
plasma gas in blowing the molten metal out of the
cut allowing for a fast, slag - free cut.