Duty Cycle And Overheating; Cutting Speed - Miller Electric Spectrum 1251 Owner's Manual

4-2. Duty Cycle and Overheating

230 Volts AC Three-Phase Input Power:
50% Duty Cycle
5 Minutes Cutting
Overheating

4-3. Cutting Speed

Rated Cutting Speed vs Material Type & Thickness
170
160
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
0.25" 0.375"
Aluminum
.
A complete Parts List is available at www.MillerWelds.com
208 Volts AC Three-Phase Input Power:
40% Duty Cycle
4 Minutes Cutting
5 Minutes Resting
0
Minutes
0.5" 0.625" 0.75"
Material Thickness (Inches)
Stainless Steel
6 Minutes Resting
380-575 Volts AC Three-Phase Input Power:
8 Minutes Cutting
15
Reduce Duty Cycle
1" 1.25"
Mild Steel
Duty Cycle is percentage of 10
minutes that unit can cut at rated
load without overheating.
If unit overheats, output stops, and
cooling fan runs. Wait fifteen min-
utes for unit to cool. Reduce amper-
age or duty cycle before cutting.
Y Exceeding duty cycle can
damage unit and void war-
ranty.
80% Duty Cycle
2 Minutes Resting
A
OR
The cutting speed curve shows the
rated cutting speed capabilities of
the power source and torch for mild
steel, stainless steel, and aluminum
of various thicknesses.
Y Exceeding
recommended
cutting speeds will cause
rapid erosion of the tip and
electrode.
OM-201 872 Page 11
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