Duty Cycle - Firepower MST 180i Operating Manual

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 welding 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.
Manual 0-5339
100
90
Firepower MST 180i
80
70
60
Safe
50
Operating
40
Region
30
20
10
0
20 40 60
0
Figure 2-1: Firepower MST 180i Duty Cycle
2-3
MIG (GMAW/FCAW)
STICK (SMAW)
80 100 120
Welding Current (amps)
Firepower MST 180i
TIG (GTAW)
140 160 180
Art # A-12545
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