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3-1.
DUTY
CYCLE
The
duty cycle
is the
percentage
of
a
ten
minute
period
that the torch
can
be
operated
at
a
given
load
without
overheating
and
damaging
the torch. The torch is rated
at
60
percent
duty cycle;
therefore,
the torch
can
be op
erated
at
10 amperes for six consecutive
minutes,
but it
must
operate
at
no
load forthe
remaining
four minutes
to
allow for
proper
cooling.
4A
CAUTION:
EXCEEDiNG THE RATED
AM
PERAGE and
duty cycle
will
damage
the
torch.
Do
not
exceed
rated
amperage and
dutycycle
stated/n
Table 3-1.
3-2.
DESCRIPTION
The model APT-i 000 torch is
designed specifically
for
the Plasma Arc
Cutting (PAC)
process. The torch
can
cut
through
all metals with the
capacity
to cut 3/16 in.
(4.7
mm)
mild steel.
The torch is
designed
to
protect
the
operatorfrom
touch
ing
live internal torch
parts.
This
safety design
is
accom
plished by
means
Of
a
shield cup detector circuit. If the
shield cup
comes
loose
or
is
removed,
the circuit is
opened.
The torch is
equipped
with
two
shield cup detec
tor
leads
which
provide
a
safety
circuit for the
operator
when
they
are
property
connected
to
the
plasma
arc
cut
ting
power
source.
These leads
are
connected
to two
pins
in
the torch head which
make contact with the
shield
cup
thereby completing
the
safety
circuit
to
the
power
source.
The power
source
must
be
designed
so
that
when this circuit is open there will be
no
power
at
the
torch.
The
alphanumeric
model
designation
refers
to
the fol
lowing:
A-Air
P
-
Plasma
T-Torch
I
1000
-
Amperage Rating:
10
Amperes
Plasma is air which has been heated
to
an
extremely
high
temperature
and ionized
so
that the air becomes.
electrically
conductive. The electrode
is located
inside
the
tip
of the torch. The torch
tip
has
a
small
opening (ori
fice)
which constricts the
arc.
The
compressed
air flows
through
the
arc
where it is heated
to
the
plasma
tem
perature
range. Since the air
cannot
expand
due
to
the
constriction of the
tip,
air is forced
through
the orifice and
emerges
in the form of
a
highly compressed
airstream.
The heat formed
by
the
arc
and the
plasma
melts the
metal,
and the
airstream forces the molten
metal from
the
cut.
SECTION
4-
INSTALLATION
IMPORTANT: See powersource Owners Manualforlo
cation of torch connections.
4-1.
REMOVING TORCH
(FIgure 4-1)
To
remove
torch,
refer
to
Figure
4-1,
and
proceed
as
fol
WARNING: ELECTRIC SHOCK
can
kIll.
Do
not
touch live electrical
parts.
Turn
off
power
source, and
remove
input
power
plug
from
receptacle
before
inspecting
or
installing.
MOVING PARTS
can cause
serIous
Injury.
Keep
away
from
moving
parts.
HOT SURFACES
can cause severe
burns.
Allow
cooling period
before
servicing.
1.
Open
lower
front
panel
access
door
or remove
wrapper,
as
applicable.
2.
Loosen strain
relief,
and
disconnect
torch cable
from
air/torch
(-)
output
connector.
3.
Disconnect
pilot
arc/shield cup detector lead
1
and
shield cup detector lead
2
from terminal
strip
iT.
4.
Disconnect
torch switch leads
3 and 4
from terminal
strip
1T.
5.
Remove
torch cable and
leads
from power
source.
4-2.
INSTALLING TORCH
(FIgure 4-1)
To install
torch,
refer
to
Figure
4-1,
and
proceed
as
follows:
Turn off power
source,
and
remove
input
power
plug
from
receptacle
before
inspecting
or
installing.
MOVING PARTS
can cause
serIous
Injury.
Keep
away
from
moving
parts.
HOT SURFACES
can cause severe
burns.
Allow
cooling period
before
servicing.
1.
Route
new
torch cable and leads
through
strain
relief.
2.
Connect
torch cable to air/torch
(-)
output
connector.
3.
Connect
pilot
arc/shield
cup detector lead
ito termi
nal
1
on1T.
4.
Connect shield cup detector
lead 2
to
terminal
2
on
iT.
5.
Connect torch switch lead
3
to
terminal 3
on
iT.
6.
Connect torch switch lead
4 to
terminal
4
on
iT.
lows:
a
4A
WARNING: ELECTRIC SHOCK
can
kIll.
Do not touch live electrical
parts.
129 326
Page
4
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