Duty Cycle; Volt-Ampere Curves - ESAB MTS 3500i Mode D'emploi

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1.6 Duty cycle

The MTS 3500i power source will operate on a 60% duty cycle with a load of 350 amperes at 34 V dc (with 3-phase input).
Duty cycle is defined as the ratio of operating time to total time. Ratings are based on a 10-minute cycle. The 60% duty
cycle rating means that the 350 ampere, 34 volt rated load can be applied for a total of 6 minutes and shut off for a total of
4 minutes in a 10-minute period. If the welding current (or voltage) is reduced, the duty cycle increases. Conversely, if the
welding current (or voltage) is increased, the duty cycle will decrease. Refer to Figure 1-2.

1.7 Volt-Ampere curves

Figure 1-2 illustrates the static volt-ampere characteristics for the power source in the MIG (CV), TIG (CC), and Stick (CC) modes.
The slant of these curves is referred to as the slope and is generally defined as the voltage drop per 100 amperes of current
rise. These curves show the output voltage available at any given output current between the minimum and maximum
settings of the output control. Values for other settings fall between the minimum and maximum curves.
These measurements are made at the output terminals of the power source. Additional voltage "drops" will occur in the
welding cable, torch cable, and in the workpiece. The use of proper size welding cable and secure electrical connections
for the electrode and ground circuits will minimize these effects which adversely affect welding conditions and waste
cv - MIg mode Volt-Amp curve
Minimum
Lift Arc Start
electrical energy.
F
M
S
AMPS
Maximum
AMPS
Figure 1-2. Volt-Ampere characteristics and Duty cycles
NotE:
Single Phase
Minimum
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Duty cycle chart
Three Phase
% Duty Cycle
Arc Force Range
Maximum
AMPS