Tweco 175i Transtig - Manual (Page 16)

TRANSMIG 175i
INTRODUCTION 2-4 Manual 0-5143
2.09 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 15% duty cycle, 90 amperes at 23.6 volts. This means that it has been designed and
built to provide the rated amperage (90A) for 1.5 minutes, i.e. arc welding time, out of every 10 minute period
(15% of 10 minutes is 1.5 minutes). During the other 8.5 minutes of the 10 minute period the Welding Power
Source must idle and be allowed to cool.
A-09520
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 (MMAW)
MIG (GMAW)
TIG (GTAW)
Figure 2-1: Transmig 175i Duty Cycle