Miller Electric Spectrum 1250, Owner'S Manual

Page: 17 / 48

OM-217 Page 13
Continuous Welding
8 Minutes Welding 2 Minutes Resting
3-2. Duty Cycle And Overheating
Duty Cycle is percentage of 10 min-
utes that unit can cut at rated load
without overheating.
If unit overheats, thermostat(s)
opens, output stops, Temperature
trouble light goes On, and cooling
fan runs. Wait fifteen minutes for
unit to cool or temperature light to
go off. Reduce amperage or duty
cycle before cutting or gouging.
Y
Exceeding duty cycle can
damage unit and void
warranty.
70 Ampere Models: 100% Duty Cycle At 70 Amperes
Overheating
0
15
duty1 4/95 – Ref. ST-159 463-B
Minutes
A
OR
Reduce Duty Cycle
100 Ampere Models: 80% Duty Cycle At 100 Amperes
3-3. Cutting Speed
The cutting speed curves show the
recommended maximum cutting
speed capabilities of the power
source and torch for mild steel of
various thickness.
Cut at speeds below the lines
shown to avoid poor cuts and torch
wear.
70 Ampere Model
ST-171 819 / ST-171 820
100 Ampere Model