Clarke PLASMA KING 25-SI Instruction Manual

OPERATION & MAINTENANCE
INSTRUCTIONS
ORIGINAL INSTRUCTIONS GC1121
PLASMA CUTTER
MODEL NO: PLASMA KING 25-SI
PART NO: 6015700

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INTRODUCTION
Thank you for purchasing this CLARKE Plasma Cutter.
Before attempting to operate the machine it is essential that you read this
manual thoroughly and carefully follow all instructions given. In doing so you
will ensure the safety of yourself and that of others around you, and you can
also look forward to the product giving you long and satisfactory service.
Ensure the machine suffered no damage during transit and that all
components are present. Should any loss or damage be apparent, please
contact your CLARKE dealer immediately.
GUARANTEE
This CLARKE product is guaranteed against faulty manufacture for a period of
12 months from the date of purchase. Please keep your receipt as proof of
purchase.
This guarantee is invalid if the product is found to have been abused or
tampered with in any way, or not used for the purpose for which it was
intended.
Faulty goods should be returned to their place of purchase, no product can
be returned to us without prior permission.
This guarantee does not effect your statutory rights.
ENVIRONMENTAL RECYCLING POLICY
Through purchase of this product, the customer is taking on the
obligation to deal with the WEEE in accordance with the WEEE
regulations in relation to the treatment, recycling & recovery and
environmentally sound disposal of the WEEE.
In effect, this means that this product must not be disposed of with general
household waste. It must be disposed of according to the laws governing
Waste Electrical and Electronic Equipment (WEEE) at a recognised disposal
facility.
If disposing of this product or any damaged components, do not dispose of
with general waste. This product contains valuable raw materials. Metal
products should be taken to your local civic amenity site for recycling of metal
products.

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SAFETY AND GENERAL WARNINGS
1. Make sure that the unit is earthed and that the supply line has an
adequate earth connection.
2. Make sure that any workbench used has a satisfactory earth connection.
3. Avoid contact between the metal being cut and bare skin or damp
clothes.
4. DO NOT lean on the workpiece being cut or hold it in your hands.
5. DO NOT use in a damp environment or on wet surfaces.
6. DO NOT use the unit if the torch or cables appear damaged.
7. ALWAYS turn the unit off before replacing the electrode, the nozzle or the
spreader tip of the torch.
8. DO NOT allow debris to collect as this could obstruct air flow to the
machine.
9. ALWAYS switch the unit off and remove the power cable from the mains
socket before carrying out any maintenance on the unit.
10. All the panels of the unit should be correctly closed after carrying out
maintenance.
HARMFUL FUMES AND GASES
Harmful fumes and metallic powders are produced during the cutting
operation. Metals which are painted or coated or which contain mercury,
cadmium, zinc, lead and graphite may produce harmful concentrations of
toxic fumes during cutting. To protect the operator or other persons from
exposure to possible toxic fumes, fume respirators should be worn and work
areas should be adequately ventilated.
When working in enclosed environments, suction units should be fitted below
the cutting areas.
CAUTION: IF DURING THE CUTTING OPERATION A SLIGHT ELECTRIC
SHOCK IS FELT, STOP WORK IMMEDIATELY AND DO NOT USE THE UNIT
UNTIL THE FAULT HAS BEEN DISCOVERED AND RESOLVED.
CAUTION: WHEN HALOGENATED SOLVENTS OR DEGREASING AGENTS
ARE PRESENT, THE MATERIAL TO BE CUT SHOULD BE CLEANED PROPERLY
TO PREVENT THE FORMATION OF TOXIC GASES. SOME CHLORINATED
SOLVENTS MAY DECOMPOSE IN THE PRESENCE OF THE RADIATION GIVEN
OUT BY THE ARC AND MAY GENERATE PHOSGENE GAS.7

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FIRE HAZARDS
1. Prevent sparks or hot scale from producing flames.
2. Remove inflammable or combustible materials from the cutting area.
3. Make sure that fire-fighting equipment is located near the work area.
4. Situate the unit in an area where the air can be sucked in and exhausted
from the grilles on the panel.
ELECTRO-MAGNETIC INTERFERENCE (EMI)
1. Make sure that there are no other power supply cables, control lines,
telephone leads or other equipment near the unit.
2. Make sure that there are no radio receivers or televisions.
3. Make sure there are no computers or other control systems.
4. Make sure that there is no-one with a pacemaker or hearing aid in the
area around the unit.
5. Check the immunity of any other equipment operating in the same
environment. In certain cases additional protective measures may be
required. Before installing the plasma cutting unit, carry out an inspection
of the surrounding area, observing the following guidelines:
Interference can be reduced in the following ways:
1. If there is interference in the power supply line, an E.M.I. filter should be
inserted between the mains and the unit.
2. The output cables of the unit should be shortened; these should be kept
close together and stretched along the ground.
PERSONAL PROTECTIVE EQUIPMENT(PPE)
One of the hazards during the cutting process is the emission of
electromagnetic waves due to the electric arc. The length of these waves
ranges from infrared to ultraviolet. If these rays hit the eyes they can cause
various complaints such as conjunctivitis, burns to the retina, deterioration of
sight, etc. Moreover a high concentration of ultraviolet rays can burn the skin.
It is, therefore, extremely important that the operator uses adequate safety
equipment and clothing, such as:
CAUTION: DO NOT CUT FUEL OR LUBRICANT CONTAINERS EVEN IF THEY
ARE EMPTY. DO NOT CUT CONTAINERS OR CASINGS WHICH CONTAIN
FLAMMABLE MATERIAL. NEVER CUT IN ENVIRONMENTS WHICH ARE
POLLUTED BY FLAMMABLE GAS OR COMBUSTIBLE LIQUID VAPOURS
(SUCH AS PETROL).

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• Leather welding gauntlets (part no 8133492)
• Leather welding apron (part no 6000920)
•Safetyshoes
• Safety mask (or even better, a helmet) large enough to cover the whole of
the face, equipped with safety lenses able to filter all the radiation and
reduce the intensity of the light absorbed by the eye.
• Safety screens should be installed around the work area to protect other
people who may be working nearby, from the radiation given out by the
arc.
THE WORK AREA
The work area should be clean and well lit. Bystanders etc should be kept
away to prevent injury or distraction.
Arrange the power cable along a safe route so as to avoid a trip hazard.
Allow enough range of movement to facilitate movement while working
keeping the cutter within 2 metres of the workpiece to be cut.
• A barrier such as a welding curtain or screen e.g. CLARKE Welding Screen
(part no 6000945) should be put up to protect others from flashing and
sparks.

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SAFETY SYMBOLS
Read Instruction
manual before use
Flammable
Caution - The user
should be aware of a
general hazard
Hot Surface - Do not
touch
Dangerous voltage Poisonous fumes - Do
not use in an enclosed
space.
Plasma cutting Thermal protection
devices
Under pressure
protection device
Wear protective
gloves
Wear a dust mask Use a protective
eyewear
Appliance for indoor
use only
This appliance falls
under the WEEE
Directive for disposal
of waste electrical
equipment.

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ELECTRICAL CONNECTIONS
Before switching the product on, make sure that the voltage of your electricity supply is
the same as that indicated on the rating plate. This product is designed to operate on
230VAC 50Hz. Connecting it to any other power source may cause damage.
This product may be fitted with a non-rewireable plug. If it is necessary to change the
fuse in the plug, the fuse cover must be refitted. If the fuse cover becomes lost or
damaged, the plug must not be used until a suitable replacement is obtained.
If the plug has to be changed because it is not suitable for your socket, or due to
damage, it should be cut off and a replacement fitted, following the wiring instructions
shown below. The old plug must be disposed of safely, as insertion into a mains socket
could cause an electrical hazard.
If the colours of the wires in the power cable of this product do not correspond
with the markings on the terminals of your plug, proceed as follows.
• The Blue wire must be connected to the terminal marked Nor
coloured Black.
• The Brown wire must be connected to the terminal marked Lor
coloured Red.
• The Yellow and Green wire must be connected to the terminal
marked E or or coloured Green.
We strongly recommend that this machine is connected to the mains supply
via a Residual Current Device (RCD). If in any doubt, consult a qualified
electrician. DO NOT attempt any repairs yourself.
WARNING! READ THESE ELECTRICAL SAFETY INSTRUCTIONS
THOROUGHLY BEFORE CONNECTING THE PRODUCT TO THE
MAINS SUPPLY.
WARNING! THE WIRES IN THE POWER CABLE OF THIS PRODUCT
ARE COLOURED IN ACCORDANCE WITH THE FOLLOWING CODE:
BLUE = NEUTRAL BROWN = LIVE YELLOW AND GREEN =
EARTH
Plug must be BS1363/A approved.
Always fit a 13 Amp fuse.
Ensure that the outer sheath of the cable is firmly held by the clamp
Neutral
(Blue)
Live
(Brown)
Earth
(Green and Yellow)

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COMPRESSED AIR REQUIREMENTS
A source of clean, dry compressed air or nitrogen must be supplied to your
plasma cutting unit. An air regulator is incorporated into the unit. A male quick
release adapter is used to connect the air supply hose to the filter/regulator.
• The operating pressure must be between 3 and 3.5 bar (0.3 and 0.35Mpa)
• The supply must also have a flow rate of approximately 7.2 cfm.
Failure to operate within the limits could result in excessive operating
temperatures or damage to the machine.
A TYPICAL AIR LINE LAYOUT IS SHOWN BELOW
Never exceed the maximum operating pressure for the machine It is
recommended that air pressure to the plasma cutter does not exceed 90 psi
at the machine. Higher pressures are a possible safety hazard.
Use only clean, dry, oil-free compressed air.
Air compressors used with the cutter must comply with the appropriate
European Community Safety Directives.
A build-up of moisture in the air compressor will accelerate wear and corrosion
in the machine. Ensure any moisture is drained from the compressor daily and
the inlet filter is kept clean.
WARNING: COMPRESSED AIR CAN BE DANGEROUS. ENSURE THAT YOU
ARE FAMILIAR WITH ALL PRECAUTIONS RELATING TO THE USE OF
COMPRESSORS AND COMPRESSED AIR SUPPLY.

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If an unusually long air hose is required, (over 8 metres), the line pressure or the
hose inside diameter may need to be increased.
NOTE: The air hose must be rated at least 150% of the maximum
operating pressure of the air tool or other machine.
PRINCIPLES OF OPERATION
PRINCIPLES OF PLASMA CUTTING
Plasma cutting is a fast, clean and distortion free, means of cutting through all
types of metal from mild and stainless steels to aluminium, brass and copper.
• An inert gas (compressed air) is blown at high speed out of the nozzle;
whilst at the same time an electrical arc travels through the gas, heating it
to an extremely high temperature, which ionizes the gas.
• The column of heated ionized gas is called “Plasma” and is a good
conductor of electricity.
• The cutting procedure utilises the plasma to transfer the electric arc to the
metal workpiece, which is melted by the heat and then blown out of the
way using the compressed air supply.
HOW THE PLASMA CUTTER WORKS
• The process is created by an arc which is struck between the electrode
(negative polarity) and the torch nozzle (positive polarity) due to the short
circuit between these two elements.
• When the torch is brought into direct contact with the workpiece
(connected to the positive polarity of the power source) the arc is
transferred between the electrode and the workpiece itself, thus striking a
plasma arc, also called cutting arc.
THERMAL PROTECTION DEVICE
• This is installed at the points most subject to high temperatures such as the
power transformers and the rectifying units. An amber light on the front
panel lights up when the thermal protection device intervenes and the
machine returns to service when it cools down.

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OVERVIEW
NO DESCRIPTION NO DESCRIPTION
1 Green “Power On” LED 8 Air Pressure gauge
2 Red “Cutting in Progress” LED 9 Earth cable connection
3 Power supply cable 10 Torch (Trigger) connection
4 Digital power display (Amps) 11 Torch (Cutting nozzle) connection
5 On/Off switch 12 Compressed air filter/regulator
6 Yellow “Overheating” LED 13 Cooling Fan
7 Control Potentiometer

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PREPARATION FOR USE
1. Connect the power supply cable
to a mains socket.
2. Connect the earthing cable into
the machine (push in and twist).
3. Connect the two screw-in
connections to the cutting torch.
4. Connect the compressed air
supply to the filter/regulator.
• An adaptor is supplied to receive
a length of hose.
5. Turn the air supply ‘ON’.
6. Pull up the air regulator knob and
turn it anticlockwise until a
pressure of 0.3 - 03.5Mpa is
displayed on the gauge.
7. When the pressure is set, push the
knob down to lock it at that
setting.
8. Fasten the earth clamp to the
workpiece. If a metal bench is
being used, make sure it has also
been connected to earth. Clamp
as close as possible to the
workpiece and take care not to
damage the cable while cutting.
• If the surface of the workpiece is
painted or rusty, clean the surface
so that satisfactory contact
between the workpiece and the
earth clamp can be obtained.

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USING THE PLASMA CUTTER
The torch can be comfortably held in one hand or steadied with two hands.
Choose the technique that feels most comfortable and allows good control
and movement. Position the index finger or thumb to depress the switch on
the torch handle.
SWITCHING ON/OFF
1. Switch the plasma cutter ON using
the ON/OFF switch.
• The green LED and the digital
display will light up on the control
panel.
• After switching off the machine,
the cooling fan will run briefly to
cool the machine down.
2. Set the desired current (10-25
amps) for the type of metal being
cut using the potentiometer knob. See cutting table on page 13.
• Thin metals require lower current.
3. DO NOT touch the torch and
cable with hot items.
4. DO NOT strain the cable.
5. DO NOT rest the cable across
sharp edges or abrasive surfaces.
6. DO NOT step on the cable.
CUTTING
1. Hold the torch firmly in the starting position squeeze the trigger switch.
• The red “Cutting” LED will illuminate and the machine will initiate a gas
purge (pre-flow) to remove any condensation that has accumulated in
the torch.
• If the cutting arc has not started after 2-3 seconds the trigger should be
released and pressed again.
2. Once on, the cutting arc remains on as long as the trigger is held down
unless the torch is withdrawn from the work or torch motion is too slow.
Keep moving while cutting.

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3. Move the cutting head more slowly for thicker and harder metals and keep
the cutting head moving while cutting.
4. If clean cutting is not achieved, adjust the control potentiometer knob to a
higher level and/or increase air flow.
CUTTING TABLE
FOR EDGE STARTS
Hold the torch perpendicular to the
workpiece with the front of the tip on
the edge of the workpiece at the
point where the cut is to start.
FOR DRAG CUTS
Keep the torch in contact with the
workpiece.
5. Cut at a steady speed without
pausing. Maintain the cutting
speed so that the arc is about 30°
behind the direction of travel.
6. Keep the torch in light contact
with the workpiece to avoid
nuisance shut off of the torch.
PIERCING WITH THE TORCH
NOTE: The recommended maximum
cutting capability from an edge is 2mm. If you need to cut sheet metal more
than 2mm without an edge start, make a hole ø 6mm using an electric drill
before you start cutting.
Thickness Steel Aluminium
0.8mm 10A clean cutting
1mm 12A clean cutting 16A clean cutting
2mm 15A clean cutting 20A clean cutting
3mm 20A clean cutting 25A clean cutting
4mm 25A clean cutting 25A severance cutting
5mm 20A severance cutting
6mm 25A severance cutting

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1. When piercing, tilt the torch so
that blowback particles blow
away from both the operator and
the torch.
2. Complete the piercing off the
cutting line and then continue the
cut onto the line. Hold the torch
perpendicular to the workpiece
after the cut is complete.
3. Clean spatter and scale from the
shield cup and the tip as soon as
possible. Spraying or dipping the
shield cup in anti-spatter
compound will minimize the scale
which adheres to it.
4. Handle torch leads with care and protect them from damage.
SHUTTING OFF THE PLASMA CUTTER
1. To stop cutting, remove the torch from the workpiece and release the
trigger.
NOTE: When the trigger is released, compressed air will continue to flow
for a short period of time in order to cool the torch. DO NOT switch
off the machine until the air has stopped flowing or damage may
occur to the torch.
2. When finished cutting and the airflow has stopped switch the cutter off
and turn off the air supply.
CAUTION: SPARKS FROM THE CUTTING PROCESS CAN CAUSE DAMAGE
TO COATED, PAINTED AND OTHER SURFACES SUCH AS GLASS, PLASTIC
AND METAL.

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TROUBLESHOOTING
Problem Possible Cause and Likely solution
Machine does
not function
when switched
on.
Tripped thermal
protection device.
Allow the machine to cool until the
yellow “Overheating” LED goes off,
then resume use. Reduce duration
of cutting periods to help reduce
load on the machine and tendency
to overheat.
Internal fuse
blown.
Return to your CLARKE dealer for
investigation.
Faulty power
switch
Return to your CLARKE dealer for
investigation.
Cutting not
stable
Loose torch cable
or earth clamp
cable.
Check that all connections are
tight.
Damaged torch
connection within
torch.
Return to your CLARKE dealer for
investigation.
Weak arc
strength
Incorrect line
voltage.
Have a qualified electrician
investigate the situation.
Arc does not
ignite
Poor ground
connection.
Make certain that the work piece
has a good connection with the
earth clamp using a clean surface
at the contact location.
Incorrectly sized or
excessively worn
nozzle.
Confirm that the nozzle is the
correct size for the torch used.
Check that the hole in the tip is not
deformed, enlarged or dirty.
Replace if required.

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Gas does not
flow
Nozzle blocked. Clean nozzle and replace if
necessary.
Air pressure
regulator not
sufficiently open.
Ensure regulator is correctly
adjusted.
Blockage in
compressed airline
Check supply hose and the hose
within the cutting torch cable.
Unit continually
overheats
Input voltage too
high or too low.
Have electrician inspect the
building power supply.
Insufficient
penetration
1. Cutting speed too high.
2. Torch is tilted.
3. Workpiece is too thick.
4. Cutting current is too low.
5. Torch parts are worn out.
Interruption of
the cutting arc
1. Cutting speed too slow
2. Excessive distance between torch and workpiece
3. AC line too low - reduce output current
4. Torch parts are worn out
5. Non-genuine manufacturer's parts
6. Work cable is disconnected
Excessive scoria
settlement
1. Too low cutting speed causing bottom dross
2. Too high cutting speed causing top dross
3. Excessive distance between torch and workpiece.
4. Cutting current too low
5. Torch parts are worn out
6. Non-genuine manufacturer's parts
Tilted cutting 1. Torch position not correct
2. Asymmetric wear of nozzle hole and/or wrong assembly
of the torch parts
Problem Possible Cause and Likely solution

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DATA PLATE INFORMATION
Excessive wear
of the nozzle
and electrodes
1. Air pressure too low
2. Exceeding system capability (material too thick)
3. Contaminated air (humidity-oil)
4. Improperly assembled torch
5. Torch tip contacting workpiece
6. Damaged or loose torch head components
7. Non-genuine manufacturer's parts
Problem Possible Cause and Likely solution

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MAINTENANCE
DO NOT open or dismantle the machine. Repairs must only be undertaken by
your CLARKE dealer.
Keep the machine clean by wiping with a soft cloth. DO NOT use abrasives.
Check that cables and leads are in good condition. If damaged, contact
your authorised service agent. Keep cables and leads clean. DO NOT use
solvents.
TORCH AND CABLE
These parts need no maintenance with the exception of a periodic inspection
and cleaning. All repairs should be carried out by a qualified service engineer.
• DO NOT use solvents or strong detergents when cleaning.
• If there is damage to the insulation such as breaks, cracks and burns or
even a loosening of electric conductors, the torch must not be used.
Manually dismantle the torch nozzle head.
To replace the consumable parts in
the torch:
1. Unscrew the shield cup from the
torch head assembly.
• Clean the shield cup thoroughly
and replace if it is damaged
(burns, distortions or cracks). If in
any doubt, replace.
2. Remove the nozzle, gas diffuser
ring and electrode.
3. Fit a new nozzle, gas diffuser ring and electrode.
• ALWAYS replace the nozzle, gas diffuser ring and electrode at the same
time.
4. Replace the shield cup and ensure that it is secure.
• Check the build-up on the emitting surface of the electrode. When the
build-up is approximately 2mm replace the electrode.
CAUTION: BEFORE PERFORMING ANY MAINTENANCE ON THE PLASMA
CUTTER TURN OFF AT THE MAINS SOCKET AND LET ALL PARTS COOL
DOWN.

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• Check that the diffuser ring is not burned or cracked and that the airflow
holes are not obstructed. If damaged replace.
5. If the nozzle surface is oxidised, clean with extra fine abrasive paper. Check
wear of the plasma arc hole and the inner and outer surfaces. If the hole
has widened, or the nozzle is damaged in any way, replace it. The nozzle
“V” crater should be 1.5mm in depth.
COMPRESSED AIR FILTER
The unit is equipped with a filter for the compressed air which captures water
and oil vapour. The filter is fitted with a plunger for the manual draining of the
condensation. Periodically drain the water in the filter.
The air filter and air filter cartridge can only be replaced by a qualified service
engineer. Contact your nearest CLARKE service department.
STORAGE AND HANDLING
Store the machine in a dry location free from damp and humidity. Always
carry the machine by its handle and avoid straining the power cable, earth
cable or torch connector.

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SPECIFICATIONS
Please note that the details and specifications contained within, are correct
at the time of going to print. However, CLARKE International reserve the right
to change specifications at any time without prior notice.
PLASMA KING 25si Part No 6015700
Power supply 230V-50Hz-1Ph
Input Current (MAX) 18A
Output current (MIN-MAX) 10A - 25A
Ingress protection Class IP21S
Compressed air pressure 0.3 - 0-35 Mpa
Compressed air flow rate 7.2 cfm
Duty cycle 25% @ 25 Amps
60% @ 16 Amps
100% @ 12.5 Amps
Weight 8.15 kg
Dimensions L x W x H 440 x 175 x 290 mm
Maximum cutting depth Steel - 4mm clean cut
6 mm rough severance
Aluminium - 3 mm clean cut
4 mm rough severance