Welding Power Source Duty Cycle And Overheating; Welding Gun Duty Cycle And Overheating - Miller Millermatic 251 Owner's Manual

4-2. Welding Power Source Duty Cycle And Overheating

500
450
400
350
300
250
200
150
100
50
10
60% Duty Cycle At 200 Amperes
6 Minutes Welding
Overheating

4-3. Welding Gun Duty Cycle And Overheating

CAUTION
WELDING LONGER THAN RATED DUTY CYCLE can damage gun and void warranty.
Do not weld at rated load longer than shown below.
Using gasless flux cored wire reduces gun duty cycle.
Definition
0
10
Minutes
Duty Cycle is percentage of 10
minutes that gun can weld at
rated load without overheating.
OM-1326 Page 10
20 30 40
% DUTY CYCLE
4 Minutes Resting
0
15
Minutes
.023 To .045 in (0.6 To 1.1 mm)
Hard Or Flux Cored Wires
100% Duty Cycle At 200 Amperes
Using CO
2
100% Duty Cycle At 150 Amperes
Using Mixed Gases
Continuous Welding
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Duty Cycle is percentage of 10
minutes that unit can weld at rated
load without overheating.
If unit overheats, Thermistor (T)
opens, output stops, and cooling
fan runs. Wait fifteen minutes for
unit to cool. Reduce amperage or
voltage, or duty cycle before
welding.
Y Exceeding duty cycle can
50 60 70 80 90 100
40% Duty Cycle At 250 Amperes
4 Minutes Welding
A or V
OR
Reduce Duty Cycle
.023 To .045 in (0.6 To 1.1 mm) Hard Or Flux Cored Wires
60% Duty Cycle At 300 Amperes
Using CO
60% Duty Cycle At 200 Amperes
Using Mixed Gases
6 Minutes Welding
damage unit and void
warranty.
6 Minutes Resting
duty1 4/95 − 150 215-A
warn7.1 8/93
2
4 Minutes Resting
SB1.1 8/93