ESAB Migmaster 275 Instruction Manual page 33

sectIon 4
Avoid gas leaks in a confined space, as the leaked gas
can dangerously reduce oxygen concentration in the
breathing air.
DO NOT bring gas cylinders into confined spaces.
When leaving a confined space, shut OFF gas supply at
the source to prevent gas from leaking into the space
if the switch is accidently kept depressed. Check the
breathing atmosphere in the confined space to be
sure it is safe to reenter.
E. Never operate the equipment at currents greater than
the rated ampere capacity; overheating will occur.
F. Never operate equipment in a damp or wet area
without suitable insulation for protection against
shock. Keep hands, feet and clothing dry at all
times.
G. Whenever the equipment is left unattended, turn
all control and power supply switches and gas
supplies OFF and open the main line switch.
H. Wear dark substantial clothing to protect exposed
skin from arcburn, sparks and flying hot metal.
I. Turn off welding power before adjusting or replacing
electrodes.
never operate the welding machine with any portion of
the outer enclosure removed. In addition to a hazard,
improper cooling may result in damage to the welding
transformer and the welding machine components.
Warranty is void if the machine is operated with any
portion of the outer enclosure removed.
4.3.2 pre-WelD reQuIreMents
Before welding commences, with all power OFF, check
the following:
A. All safety requirements have been read and under-
stood.
B. All hoses and cables are in good condition, safely
insulated and securely connected.
C. Turn on gas supply by slowly opening cylinder
valve to full ON.
D. Correct size wire accessories have been installed
on the wire feeder, drive gears are meshed, wire
pressure set, and guide tube is installed for type
and size wire you plan to use, refer to Tables
3.1 and Figure 4.7.
E. Spool of correct size wire is locked in place, brake
tension is set, and wire is properly threaded through
the inlet guide to the gun tip.
F. The wire feeding compartment cover is closed and
secure.
G. Make sure that the metal to be welded is properly
prepared:
a. Remove loose surface rust, scale or paint with
wire brush or sander.
b. Attempting to weld over grease or oil will cause
weld defects.
c. Before welding on aluminum, be sure to clean
surface thoroughly using a stainless steel brush.
4.3.3 set-up proceDure
A. Determine the material type, thickness and joint
configuration to be welded from Table 4.2 and use
the recommendations to set the following:
a. Coarse Voltage Range.
b. Fine Arc Voltage Setting.
c. Wire Speed setting.
B. Set the two-position switch in the wire feeder compart-
ment to STANDARD for seam welding with the GUN-
MASTER 250 torch. (For ST-23A Spool-On-Gun welding,
see Section 4.2.2).
C. If optional Burn Back module is installed, refer to Sec-
tion 4.2.3 for operation, settings and welding condition
table.
D. Make sure the GUNMASTER 250 gun fitting and the "Work"
cable are connected to the proper output terminals
for the polarity desired.
only qualified personnel should make these changes. Make
certain the primary power has been disconnected and all
safety procedures have been followed before proceeding
with these instructions.
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operatIon