MK Products CobraTurn Digital Turntable - Manual (Page 6)

1-3 ARC WELDING
Comply with precautions in 1-1, 1-2,
and this section. Arc Welding, properly
done, is a safe process, but a careless
operator invites trouble. The equipment
carries high currents at significant volt-
ages. The arc is very bright and hot.
Sparks fly, fumes rise, ultraviolet and
infrared energy radiates, weldments
are hot, and compressed gases may
be used. The wise operator avoids
unnecessary risks and protects himself
and others from accidents.
A. Burn Protection
Comply with precautions in 1-2.
The welding arc is intense and visibly
bright. Its radiation can damage eyes,
penetrate lightweight clothing, reflect
from light-colored surfaces, and burn
the skin and eyes. Skin burns resemble
acute sunburn; those from gas-shielded
arcs are more severe and painful. DON’T
GET BURNED; COMPLY WITH PRE-
CAUTIONS.
1. Protective Clothing
Wear long-sleeve clothing in addition to
gloves, hat, and shoes. As necessary,
use additional protective clothing such
as leather jacket or sleeves, flameproof
apron, and fire-resistant leggings. Avoid
outer garments of untreated cotton.
Bare skin protection. Wear dark, sub-
stantial clothing. Button collar to protect
chest and neck, and button pockets to
prevent entry of sparks.
2. Eye and Head Protection
Protect eyes from exposure to arc. Eyes
may be damaged by radiant energy
when exposed to the electric arc, even
when not looking in the direction of the
arc. Never look at an electric arc without
protection.
Welding helmet or shield containing a
filter plate shade no. 12 or denser must
be used when welding. Place over face
before striking arc.
Protect filter plate with a clear cover
plate.
Cracked or broken helmet or shield
should NOT be worn; radiation can be
passed through to cause burns.
Cracked, broken, or loose filter plates
must be replaced IMMEDIATELY.
Replace clear cover plate when broken,
pitted, or spattered.
Flash goggles with side shields MUST
be worn under the helmet to give some
protection to the eyes should the helmet
not be lowered over the face before
an arc is struck. Looking at an arc
momentarily with unprotected eyes
(particularly a high intensity gas-shielded
arc) can cause a retinal burn that may
leave a permanent dark area in the field
of vision.
3. Protection of Nearby Personnel
Enclose the welding area. For production
welding, a separate room or enclosed
bay is best. In open areas, surround the
operation with low-reflective, noncombus-
tible screens or panels. Allow for free air
circulation, particularly at floor level.
Viewing the weld. Provide face shields for
all persons who will be looking directly
at the weld.
Others working in area. See that all persons
are wearing flash goggles.
Before starting to weld, make sure that
screen flaps or bay doors are closed.
B. Toxic Fume Prevention
Comply with precautions in 1-2B.
Generator engine exhaust must be vented
to the outside air. Carbon monoxide can
kill.
C. Fire and Explosion Prevention
Comply with precautions in 1-2C.
Equipment’s rated capacity. Do not overload
arc welding equipment. It may overheat
cables and cause a fire.
Loose cable connections may overheat or
flash and cause afire.
Never strike an arc on a cylinder or other
pressure vessel. It creates a brittle area that
can cause a violent rupture or lead to such
a rupture later under rough handling.
D. Compressed Gas Equipment
Comply with precautions in 1-2D.
E. Shock Prevention
Exposed electrically hot conductors or
other bare metal in the welding circuit, or in
ungrounded, electrically-HOT
equipment can fatally shock a person
whose body becomes a conductor. DO
NOT STAND, SIT, LIE, LEAN ON, OR
TOUCH a wet surface when welding without
suitable protection.
To protect against shock:
Keep body and clothing dry. Never work
in damp area without adequate insulation
against electrical shock. Stay on a dry
duckboard, or rubber mat when dampness
or sweat cannot be avoided. Sweat, sea
water, or moisture between body and
an electrically HOT part - or grounded
metal - reduces the body surface electri-
cal resistance, enabling dangerous and
possibly lethal currents to flow through
the body.
1. Grounding the Equipment
When installing, connect the frames of
each unit such as welding power source,
control, work table, and water circulator to
the building ground. Conductors must be
adequate to carry ground currents safely.
Equipment made electrically HOT by stray
currents may shock, possibly fatally. Do
NOT GROUND to electrical conduit, or to
a pipe carrying ANY gas or a flammable
liquid such as oil or fuel.
Three-phase connection. Check phase
requirement of equipment before installing.
If only three-phase power is available,
connect single-phase equipment to only
two wires of the three-phase line. Do NOT
connect the equipment ground lead to
the third (live) wire, or the equipment
will become electrically HOT - a danger-
ous condition that can shock, possibly
fatally.
Before welding, check ground for continu-
ity. Be sure conductors are touching
bare metal of equipment frames at con-
nections.
If a line cord with a ground lead is
provided with the equipment for connec-
tion to a switch box, connect the ground
lead to the grounded switch box. If a
three-prong plug is added for connection
to a grounded mating receptacle, the
ground lead must be connected to the
ground prong only. If the line cord comes
with a three-prong plug, connect to a
grounded mating receptacle. Never
remove the ground prong from a plug, or
use a plug with a broken ground prong.
2. Connectors
Fully insulated lock-type connectors
should be used to join welding cable
lengths.
3. Cables
Frequently inspect cables for wear,
cracks, and damage. IMMEDIATELY
REPLACE those with excessively worn
or damaged insulation to avoid possibly
lethal shock from bared cable. Cables
with damaged areas may be taped to
give resistance equivalent to original
cable.
Keep cable dry, free of oil and grease,
and protected from hot metal and
sparks.
4. Terminals and Other Exposed
Parts
Terminals and other exposed parts of
electrical units should have insulating
covers secured before operation.
5. Electrode Wire
Electrode wire becomes electrically HOT
when the power switch of gas metal-arc
welding equipment is ON and welding
gun trigger is pressed. Keep hands
and body clear of wire and other HOT
parts.
6. Safety Devices
Safety devices such as interlocks and
circuit breakers should not be discon-
nected or shunted out.
Before installation, inspection, or service
of equipment, shut OFF all power, and
remove line fuses (or lock or red-tag
switches) to prevent accidental turning
ON of power. Disconnect all cables from
welding power source, and pull all 115
volts line-cord plugs.
Do not open power circuit or change
polarity while welding. If, in an emer-
gency, it must be disconnected, guard
against shock burns or flash from switch
arcing.
Leaving equipment unattended. Always
shut OFF, and disconnect all power to
equipment.
Power disconnect switch must be avail-
able near the welding power source.