ESAB Migmaster 275, Instruction Manual

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sectIon 4 operatIon
4.2.5 Volt/aMpere curVes (figure 4.6)
The Volt/Ampere curves show the output Voltage available
at any given output current for the various Voltage Selector
positions in each range low, medium, and high.
4.3 operatIng proceDures
4.3.1 operatIng safetY precautIons
Comply with all ventilation, fire and other safety require-
ments for arc welding as established in the SAFETY Section
at the front of this manual.
Also remember the following:
A. Because of the radiant energy of the welding arc
and the possibility of drawing an arc before the
helmet is lowered over the face, the operator should
wear flash goggles with filter lenses under his helmet.
The helmet filter plated should be shade number
11 (nonferrous) or 12 (ferrous). All those viewing the
arc should use helmets with filter plates, as well as
flash goggles. Nearby personnel should wear flash
goggles.
fig. 4.6 Volt/amp curves
B. The radiant energy of the arc can decompose chlorinated
solvent vapors, such as trichloroethylene and perchlor-
ethylene, to form phosgene, even when these vapors
are present in low concentrations. DO NOT weld where
chlorinated solvents are present in atmospheres in or
around the arc.
C. DO NOT touch the electrode, nozzle or metal parts in
contact with them when power in ON: all are electrically
energized (HOT) and can cause a possibly fatal shock.
DO NOT allow electrode to touch grounded metal: it
will create an arc flash that can injure eyes. It may also
start a fire or cause other damage.
D. When working in a confined space, be sure it is safe to
enter. The confined space should be tested for adequate
oxygen (at least 19%) with an approved oxygen measur-
ing instrument. The confined space should not contain
toxic concentrations of fumes or gases. If this cannot be
determined, the operator should wear an approved
air supplied breathing apparatus.
The actual operating point of load Voltage and Current
is determined by type of process, electrode, shield gas,
wire feed speed, and operating technique.