Tweco 550i Transmig - Manual (Page 17)

TRANSMIG 350i, 450i, 550i
Manual 0-5205 2-5 INTRODUCTION
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 60% duty cycle, 550 amperes at 41.5 volts. This means that it has been designed
and built to provide the rated amperage (550A) for 6 minutes, i.e. arc welding time, out of every 10 minute
period (60% of 10 minutes is 6minutes). During the other 4minutes of the 10 minute period the Welding
Power Source must idle and allowed to cool. The thermal cut out will operate if the duty cycle is exceeded.
25 50 75 100 125 150 175 200 225 250 275 300 325 350 375 400 425 450 475 500 525 550
TRANSMIG
550i
TRANSMIG
450i
TRANSMIG
350i
Welding Current (AMPS)
SAFE OPERATING REGION
(MIG, STICK & TIG )
0
0
10
20
30
40
60
70
50
80
100
90
Duty Cycle (PERCENTAGE)
A-10626
Figure 2-1: Transmig 350i, 450i, 550i Duty Cycle