EN
4-3.
Duty Cycle Curve
Warning: Work in Overload is Harmful to the Welding Machine
67
34
10
0
600
I
2
（
A
）
U
2
（
V
）
Working
point
Volt-ampere characteristic
The relation between the
conventional loading
voltage and welding current
4-4. Volt-Ampere
Characteristic
TIG 220 DIGITAL PULSE RC welding machine has an excellent volt-ampere characteristic, whose
graph is shown as the following
fi
gure.
The relation between the conventional rated loading voltage U
2
and the conventional welding
current I
2
is as follows:
When I
2
≤
600A
≤
U
2
=10+0.04I2(V); When I
2
≥
600A,U
2
=34(V).
The letter “X” stands for duty cycle, which is
de
fi
ned as the proportion of the time that a
machine can work continuously within a certain
time (10 minutes). The rated duty cycle means
the proportion of the time that a machine can
work continuously within 10 minutes when it
outputs the rated welding current.
The relation between the duty cycle “X” and
the output welding current “I” is shown as the
right
fi
gure.
If the welder is over-heat, the IGBT over-heat
protection unit inside it will output an instruction
to cut output welding current, and brighten
the over-heat pilot lamp on the front panel. At
this time, the machine should be relaxed for 15
minutes to cool the fan. When operating the
machine again, the welding output current or
the duty cycle should be reduced.
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