Fronius TransSteel 2700c, Operating Instructions Manual

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Options
VRD: safety func-
tion A Voltage Reduction Device (VRD) is an optional safety device for reducing the voltage.
It is recommended for environments in which the risk of an electric shock or electrical
accident is increased considerably during arc welding:
-
Due to a low human body resistance of the welder
- If the welder is exposed to a clear risk of touching the workpiece or other parts of the
welding circuit
A low human body resistance is possible when there is:
-
water in the area
- humidity
- heat, particularly ambient temperatures in excess of 32°C (89.6°F)
In wet, damp or hot locations, humidity or sweat can significantly reduce the skin resist-
ance and the insulation resistance of protective equipment and clothing.
Such environments can include:
-
Temporary dams for draining certain areas of a site during construction work (coffer-
dams)
- Trenches
- Mines
- Rain
- Areas partly submerged by water
- Spraywater areas
The VRD option reduces the voltage between the electrode and the workpiece. In safe
conditions, the indicator for the currently selected welding process is permanently lit. A
safe condition is defined as follows:
-
The output voltage in an open circuit is limited to 35 V.
For as long as the welding operation is active (welding circuit resistance < 200 Ohm), the
indicator of the currently selected welding process flashes and the output voltage may
exceed 35 V.
VRD: safety prin-
ciple The welding circuit resistance is greater
than the minimum human body resistance
(greater than or equal to 200 Ohm):
-
VRD is active
- Open circuit voltage is limited to 35 V
- Unintentional contact with the output
voltage does not put the welder at risk
The welding circuit resistance is less than
the minimum human body resistance (less
than 200 Ohm):
-
VRD is inactive
- Output voltage not restricted in order
to ensure sufficient welding power
- Example: Welding starts
In MMA welding mode:
Within 0.3 seconds of end of welding:
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