Safety Rules For Operation Of Arc Welding Machine; General; Welding Cables; Electrode Holder - Miller Two Fifty Twin Owner's Manual

SECTION
1-
SAFETY RULES
FOR
OPERATION OF ARC WELDING MACHINE
1
-
1. GENERAL
These rules
apply
to
ac
and dc
welding
generators.
ac
trans
former and ac/dc
welding machines,
and dc transformer recti
fier welding machines.
In arc-welding operations, where
electrically energized
parts
are
exposed, observe the
following safety
rules
to
insure
max
imum
personal safety and protect
nearby
persons.
Failure
to
observe these safety
precautions
may expose
not
only
you,
but fellow workers
as
well,
to
serious injuries. Once
these rules
are
learned and
kept
in
mind, proceed with maxi
mum assurance.
1 -2. WELDING CABLES
Figure 1-1. Dont overload cables
NEVER
use
welding cables
at currents
in
excess
of their rated
capacity. It will
cause
overheating and
rapid deterioration of
the insulation. It is also uneconomical.
DONT
use worn or
poorly connected cables. )Figure 1-2)
Inspect the cables frequently. Immediately repair
all breaks
in the insulation with rubber and friction
tapes.
Tighten all
cable connections and
adequately insulate
any
joints where
a
connector
may
have
an
exposed conductive part. In addition
to
the potential hazard
to
life,
a
hazard
occurs
when
exposed
sections of cable
come
in
contact
with grounded metallic
objects, causing
an
arc.
Unprotected eyes may be injured and
fire
may
result if combustible materials such
as
oil
or grease
are
in the vicinity. The efficiency
and quality of welding will
be improved by elimination of these
dangerous grounds, and
by keeping
connections tight.
1
-
3. ELECTRODE HOLDER
DONT
use
electrode holders with defective
jaws.
(Figure
1-3)
Keep the jaws of the electrode holder
tight
and the
gripping
surfaces in
good
condition
to
provide close
contact
with the
electrodes. Defective jaws
will permit the electrode
to
wob
ble, making
control of the
welding operations difficult.
Figure
1-3. Dont
use
Electrode Holder with defective
jaws
DONT
use
electrode holder with loose cable connections.
Keep the connections of the electrode lead
to
the holder
tight
at
all times.
Use
only
fully insulated electrode holders
(and without
pro
truding screwheads.)
Never touch
two
electrode holders from
two
separate
welding
machines
at
the
same
time.
1 -4. CODE CONFORMANCE
The machine and its equipment
must
be installed and main
tained in accordance with the National Electrical Code and
local requirements.
1 -5. PARALLEL CONNECTIONS
See
diagrams in the instruction manual applying
to
the weld
ing machine used.
1
-
6. POWER DISCONNECT SWITCH
If the welding machine does
not
include
a
power disconnect
switch, install
one
at
or near
the machine.
1 .7. POLARITY SWITCH
DONT operate the
polarity
switch under load.
The polarity switch (when supplied) is provided for changing
the electrode lead from
positive
(reverse polarity)
to
negative
(straight polarity).
Never
move
it while under the load of
a
welding current.
Operate this switch
only
while the machine
is idling and the welding Circuit
5
open. The potential dan
gers of opening the Circuit while
carrying high
current are:
1. An
arc
will form between the
contact
surfaces of the
switch and
severely
burn them.
2. The person
throwing the switch
may
receive
a severe
burn
from this
arcing.
1- 8. RANGE SWITCH
DONT
operate
the range switch under load.
The range switch lwhen
supplied) is provided for
obteining
required
current
settings. It
must
never
be operated while the
machine is under the load of
welding
current.
Operate the
range switch only while the machine is
idling and the welding
circuit is
open.
The
potential danger of switching the Circuit
while
carrying high
current
is the formation of
an arc
be
tween
the
contact
surface which will
severely burn them.
Repeated
occurrences
of this
arcing will
eventually prevent
operation of the
contacts.
1
-
9. EXHAUST GASES
DONT
use gas
engine
units in Confined spaces without
vent
ing the exhaust gases.
)Figure 1-4)
If
gasoline
or
other fuel driven welding machines
are
operated
indoors, provide
means to
pipe
the exhaust gases
to
the
Out
side air
to
avoid carbon monoxide
poisoning.
DONT overload
cables, (Figure
1-1)
Figure 1-2. Dont
use worn or
poorly connected cables
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