Tweco 181i Thermal Arc Fabricator - Manual (Page 27)

Fabricator 181i
Manual 0-51 91 2-3 INTRODUCTION
2.08 Duty Cycle
The rated duty cycle of a Welding Power Source, is a statement of the time it may be operated at its rated weld-
ing current output without exceeding the temperature limits of the insulation of the component parts. To explain
the 10 minute duty cycle period the following example is used. Suppose a Welding Power Source is designed to
operate at a 20% duty cycle, 180 amperes at 23 volts. This means that it has been designed and built to provide
the rated amperage (180 A) for 2 minutes, i.e. arc welding time, out of every 10 minute period (20% of 10 minutes
is 2 minutes). During the other 8 minutes of the 10 minute period the Welding Power Source must idle and be
allowed to cool.
A-10352
Duty Cycle (per
centage)
Safe
Operating
Region
0 20 40 60
80
100
120 140 160 180
30
50
70
90
40
60
20
10
80 100
0
Welding Current (amps)
STICK (SMAW)
TIG (GTAW)
MIG (GMAW/FCAW)
Figure 2-1: Fabricator 181i Duty Cycle