Tweco 186 DC Inverter - Manual (Page 27)

INTRODUCTION 186 AC/DC INVERTER
Manual 0-5237 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, 200 amperes at 18.0 volts. This means that it has been designed and built to provide
the rated amperage (200A) 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. The thermal cut out will operate if the duty cycle is exceeded.
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220
Welding Current (AMPS)
SAFE OPERATING REGION
(TIG & STICK)
0
0
10
20
30
40
60
70
50
80
100
90
Duty Cycle (PERCENTAGE)
GTAW (TIG)
SMAW (STICK)
A-11493
186 AC/DC
Figure 2-2: 186 AC/DC Duty Cycle