CIGWELD 250i Transmig, Service Manual

Page: 17 / 128

INTRODUCTION TRANSMIG 250i
Manual 0-5188 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 cur-
rent 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 40%
duty cycle, 250 amperes at 26.5 volts. This means that it has been designed and built to provide the rated amperage
(250A) for 4 minutes, i.e. arc welding time, out of every 10 minute period (40% of 10 minutes is 4 minutes). During
the other 6 minutes of the 10 minute period the Welding Power Source must idle and be allowed to cool.
Art # A-10315
Duty Cycle (per
centage)
Safe
Operating
Region
0
25 50 75
80
100
125 150 225 250
30
50
70
90
40
60
20
10
100
0
Welding Current (amps)
Stick (MMAW)
TIG (GTAW)
MIG (GMAW)
175
200
With Factory Installed Input Lead and Plug
Figure 2-2: Transmig 250i Duty Cycle with Factory Fitted Supply Lead and Plug
Art # A-10316
Duty Cycle (per
centage)
Safe
Operating
Region
0
25 50 75
80
100
125 150 225 250
30
50
70
90
40
60
20
10
100
0
Welding Current Max (amps)
Stick (MMAW)
TIG (GTAW)
MIG (GMAW)
175
200
With Upgraded Supply Lead and Plug
Figure 2-3: Transmig 250i Duty Cycle with Upgraded Supply Lead and Plug