Clarke King 35 Installation and operation manual

OPERATING & MAINTENANCE
INSTRUCTIONS 1/97
PLASMA CUTTERS
Model Nos.
King 35 • King 50 • King 70

SPECIFICATIONS
King35 King50 King70
Supply Voltage 230V 230V 230/400V
No. of phases IPH 1PH 3PH
Frequency 50/60HZ 50/60 HZ 50/60 HZ
Max. Input Current (230V) 18A 31A 46A
Max. Input Current (400V) - - 26A
Fuse Rating T20A (230V) T30A (230V) T35A(230) T25A(400)
Cutting Depth - (Steel Class C) 4MM 10MM 15MM
No. Current Settings 1 2 2
Working Air Pressure 5 to 5.5 BAR 5 to 5.5 BAR 5 to 5.5 BAR
Rated Air Delivery 100 L/MIN 105 L/MIN 210 L/MIN
Protection IP21 IP21 IP21
Insulation Clas H H H
Weight 30KG 50KG 83KG
Dimensions 250x500x380 456x610x695 456x610x695
For wiring diagrams and parts lists, please refer to
the accompanying booklet.
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CONTENTS Page
Specifications ................................................................................................ 1
EMC Regulations .......................................................................................... 3
Safety Precautions - General ...................................................................... 5
Additional Safety Precautions for Plasma Cutters .................................... 7
What is Plasma Cutting ................................................................................. 8
Features ......................................................................................................... 8
Air Supply ....................................................................................................... 9
Front Panel Description ............................................................................... 9
Electrical Connections ................................................................................ 11
Installation & Operation ............................................................................... 12
Duty Cycle .................................................................................................... 14
Maintenance ............................................................................................... 15
Troubleshooting ............................................................................................ 16
Thank you for purchasing this CLARKE Plasma Cutter .
Before attempting to operate this machine, please read this leaflet thoroughly
and follow the instructions carefully, in doing so you will ensure the safety of yourself
and that of others around you, and you can look forward to the Plasma Cutter
giving you long and satisfactory service.
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.

ELECTROMAGNETIC INTERFERENCE (EMC)
Whilst this unit complies with EMC regulations, the user is responsible for installing
and using the welding equipment according to the manufacturers instructions. If
electromagnetic disturbances are detected then it shall be the responsibility of
the user of the welding equipment to resolve the situation. In some cases this
remedial action may be as simple as earthing the welding circuit, see ‘Note’. In
other cases it could involve constructing an electromagnetic screen enclosing
the power source and the work complete with associated input filters. In all cases
electromagnetic disturbances must be reduced to the point where they are no
longer troublesome.
Note - The welding circuit may or may not be earthed for safety reasons. Changing
the earthing arrangements should only be authorised by a person who is
competent to assess whether the changes will increase the risk of injury, e.g. by
allowing parallel welding current return paths which may damage the earth circuits
of other equipment.
1. Assessment of area
Before installing welding equipment the user shall make an assessment of potential
electromagnetic problems in the surrounding area. Avoid using your inverter in
the vicinity of:
a) other supply cables, control cables, signalling and telephone cables;
above, below and adjacent to the welding equipment;
b) radio and television transmitters and receivers;
c) computer and other control equipment;
d) safety critical equipment, e.g. guarding of industrial equipment;
e) pacemakers and hearing aids etc;
f) equipment used for calibration or measurement;
g) other equipment in the environment. The user shall ensure that other
equipment being used in the environment is compatible. This may
require additional protection measures;
It may be possible to avoid the above by changing the time of day that welding
or other activities are to be carried out.
The size of the surrounding area to be considered will depend on the structure of
the building and other activities that are taking place. The surrounding area may
extend beyond the boundaries of the premises.
2. Methods of reducing emissions
2.1 Mains supply
Welding equipment should be connected to the mains supply according to the
manufacturers recommendations. If interference occurs, it may be necessary to
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take additional precautions such as filtering of the mains supply. Consideration
should be given to shielding the supply cable of permanently installed welding
equipment, in metallic conduit or equivalent. Shielding should be electrically
continuous throughout its length. The shielding should be connected to the welding
power source so that good electrical contact is maintained between the conduit
and the welding power source enclosure.
2.2 Maintenance of the welding equipment
The welding equipment should be routinely maintained according to the
manufacturers recommendations. All access and service doors and covers should
be closed and properly fastened when the welding equipment is in operation.
The welding equipment should not be modified in any way except for those
changes and adjustments covered in the manufacturers
instructions. In particular, the spark gaps of arc striking and stabilizing devices should
be adjusted and maintained according to the manufacturers recommendations.
2.3 Welding cables
The welding cables should be kept as short as possible and should be positioned
close together, running at or close to the floor level.
2.4 Equipotential bonding
Bonding of all metallic components in the welding installation and adjacent to it
should be considered. However, metallic components bonded to the work piece
will increase the risk that the operator could receive a shock by touching these
metallic components and the electrodes at the same time. The operator should
be insulated from all such bonded metallic components.
2.5 Earthing of the workpiece
Where the workpiece is not bonded to earth for electrical safety, nor connected
to earth because of its size and position, e.g. ships hull or building steelwork, a
connection bonding the workpiece to earth may reduce emissions in some, but
not all instances.
Care should be taken to prevent the earthing of the workpiece increasing the risk
of injury to users, or damage to other electrical equipment.
Where necessary, the connection of the workpiece to earth should be made by
a direct connection to the workpiece, but in some countries where direct
connection is not permitted, the bonding should be achieved by suitable
capacitance, selected according to national regulations.
2.6 Screening and shielding
Selective screening and shielding of other cables and equipment in the surrounding
area may alleviate problems of interference. Screening of the entire welding
installation may be considered for special applications.

SAFETY PRECAUTIONS
WARNING:
As with all machinery, there are certain hazards involved with their operation
and use. Exercising respect and caution will considerably lessen the risk of
personal injury. However, if normal safety precautions are overlooked, or
ignored, personal injury to the operator may result.
FAILURE TO FOLLOW THESE RULES MAY RESULT IN SERIOUS PERSONAL INJURY
GENERAL PRECAUTIONS
A) Burn prevention
Wear protective clothing - gauntlet gloves designed for use in welding, hat, and
protective shoes. Button shirt collar and pocket flaps, and wear cuffless trousers to
avoid entry of sparks and slag. Wear helmet with safety goggles or glasses with side
shields underneath, appropriate filter lenses or plates (protected by clear cover
glass). This is a MUST for welding or cutting, (and chipping) to protect the eyes from
radiant energy and flying metal. Replace cover glass when broken, pitted, or
spattered. Avoid oily greasy clothing. A spark may ignite them. Hot metal such as
electrode stubs and workpieces should never be handled without gloves. First aid
facilities and a qualified first aid person should be available for each shift unless
medical facilities are close by for immediate treatment of flash burns of the eyes
and skin burns. Ear plugs should be worn when working overhead or in a confined
space. A hard hat should be worn when others work overhead. Flammable hair
preparations should not be used by persons intending to weld or cut.
B) Toxic fume prevention
Severe discomfort, illness or death can result from fumes, vapours, heat, or oxygen
enrichment or depletion that welding (or cutting) may produce. Prevent them
with adequate ventilation. NEVER ventilate with oxygen. Lead-, cadmium-, zinc-,
mercury- and beryllium-, bearing materials, when welded (or cut) may produce
harmful concentrations of toxic fumes. Adequate local exhaust ventilation must
be used, or each person in the area as well as the operator must wear an air-
supplied respirator. For beryllium, both must be used. Metals coated with or
containing materials that emit toxic fumes should not be heated unless coating is
removed from the work surface, the area is well ventilated, or the operator wears
an air-supplied respirator. Work in a confined space only while it is being ventilated
and, if necessary, while wearing an air-supplied respirator. Vapours from chlorinated
solvents can be decomposed by the heat of the arc (or flame) to form PHOSGENE,
a highly toxic gas, and other lung and eye irritating products. The ultraviolet
(radiant) energy of the arc can also decompose trichloroethylene and
perchloroethylene vapours to form phosgene. DO NOT WELD or cut where solvent
vapours can be drawn into the welding or cutting atmosphere or where the radiant
energy can penetrate to atmospheres containing even minute amounts of
trichloroethylene or perchloroethylene.
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C) Fire and explosion prevention
Causes of fire and explosion are:
1) combustibles reached by the arc, flame, flying sparks, hot slag or heated
material;
2) misuse of compressed gases and cylinders;
3) short circuits.
BE AWARE THAT flying sparks or falling slag can pass through cracks, along pipes,
through windows or doors, and through wall or floor openings, out of sight of the
goggled operator. Sparks and slag can fly 10m.
To prevent fires and explosion: keep equipment clean and operable, free of oil,
grease, and (in electrical parts) of metallic particles that can cause short circuits.
If combustibles are in area, do NOT weld or cut. Move the work if practicable, to
an area free of combustibles.
Avoid paint spray rooms, dip tanks, storage areas, ventilators. If the work cannot
be moved, move combustibles at least 10m. away out of reach of sparks and
heat; or protect against ignition with suitable and snug fitting, fire- resistant covers
or shields.
Walls touching combustibles on opposite sides should not be welded on (or cut).
Walls, ceilings, and floor near work should be protected by heat resistant covers
or shields. Fire watcher must be standing by with suitable fire extinguishing
equipment during and for some time after welding or cutting if:
a) appreciable combustibles (including building construction) are within 10m.
b) appreciable combustibles are further than 10m but can be ignited by sparks.
c) openings (concealed or visible) in floors or walls within 10m can expose
combustibles to sparks.
d) combustibles adjacent to walls, ceilings, roofs or metal partitions can be
ignited by radiant or conducted heat.
After work is done, check that area is free of sparks, glowing embers, and flames.
An empty container that held combustibles, or that can produce flammable or
toxic vapours when heated, must never be welded on or cut, unless container
has first been cleaned. This includes
.......a thorough steam or caustic cleaning (or a solvent or water washing,
depending on the combustible’s solubility) followed by purging and inerting with
nitrogen or carbon dioxide, and using protective equipment.
Water filling just below working level may substitute for inerting.
A container with unknown contents should be cleaned (see paragraph above),
do NOT depend on sense of smell or sight to determine if it is safe to weld or cut.
Hollow castings or containers must be vented before welding or cutting - they
can explode.
In explosive atmospheres, never weld or cut where the air may contain flammable
dust, gas, or liquid vapours.

The safety precautions given previously must be strictly adhered to. The following
precautions are additional to, and focus specifically on Plasma Cutters.
ALWAYS have a fire extinguisher handy when operating the cutter.
ALWAYS wear protective clothing - overalls, gloves and sturdy footwear, To
avoid the risk of burns,
ALWAYS ensure that the cutting cable, air compressor hose and electrical
input lead are kept well away from the possible ‘spatter’ of hot metal created
when cutting.
ALWAYS operate the cutter in a well ventilated area or an area equipped
with a fume extractor. Check the possibility that the material to be cut will
give off toxic gas or fumes. If there is any doubt, a respirator should worn.
NEVER operate near water or any other liquid.
NEVER operate near anything flammable. Whilst plasma cutters do not produce
an open flame, they do produce very hot metal during the cutting process, hot
enough to set alight flammable materials, should contact be made.
NEVER observe the electric plasma arc with the naked eye. Always wear
eye protection such as welding goggles used for oxy-acetylene welding.
Should the cutting cable be burned, replace it NEVER attempt to repair it
yourself.
NEVER operate the machine with the covers removed.
NEVER dismantle the tip from the torch unless the machine has been
disconnected from the electrical supply.
NEVER push the torch nozzle down with your hands unless the machine has
been disconnected from the electrical supply.
NEVER cut fuel or lubricant containers, even if they are empty.
NEVER cut containers or casings which contain flammable material.
NEVER cut in environments which are polluted by flammable gas or
combustible vapours, such as petrol etc.
NEVER point the torch jet at people or animals.
Should you feel sick or develop sore eyes whilst using the plasma cutter, STOP
WORK IMMEDIATELY and move to fresh air. Do not resume cutting until you
have provided good ventilation for the cutting area.
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 phosphene gas.
ADDITIONAL SAFETY PRECAUTIONS FOR PLASMA CUTTERS
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WHAT IS 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.
The process relies upon the chemical reaction of a gas or mixture of gases, such
as air, when subjected to very high temperatures. The gas ionises, i.e. negative
electrons are separated from the atom, leaving the atom positively charged. In
this ionised state, the gas is electrically conductive and is called ‘plasma’.
A standing electric arc is created to achieve the very high temperature required
to create the plasma. By forcing the plasma through a small nozzle the arc is
constricted and its temperature is increased to over 20,000°C and concentrated
into a very small area.
When the plasma is directed at a conductive material (which is connected to
the earth return lead of the cutter) the arc is transferred through the plasma to
the material. The high energy of the arc melts the material which is displaced by
the gas flow.
The standing arc has to be created by producing an ionised path in the gas. This
is achieved by applying a very high voltage, at high frequency, between the
electrode and the tip/work, causing a high frequency spark. The main arc will
ignite as soon as the gas between the tip and the nozzle is ionised.
The power generator is essentially made up of a transformer, a rectifying unit and
an electronic board.
The latter controls the unit safeguards and governs the work cycles of the various
components which make up the unit, such as the solenoid valve, the HF circuit
(for models fitted with this), the power contactor, etc.
FEATURES
The plasma cutting units are supplied with the following safety devices:
1. Thermal protection devices are 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. See fig.3
2. A pneumatic protection device prevents damage to the torch due to
switching on with either no air supply or low air pressure.
An amber light on the front panel lights up when the pneumatic protection
device intervenes. See fig. 3
3. An Electric shock protection device prevents the operator from coming into
contact with the live parts of the torch (such as the electrode, etc.) This consists
of a safety device, built into the body of the torch, which breaks the main
power circuit when the end part of the torch is removed to replace the
electrode or the tip.
When the electrical protection device intervenes, the unit is prevented from
operating.
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MAIN COMPONENTS
The power generator is essentially made up of a transformer, a rectifying unit
and an electronic board.
The latter controls the unit safeguards and governs the work cycles of the various
components which make up the unit, such as the solenoid valve, the power
contactor, etc.
MAIN
CONTACTOR MAIN
TRANSFORMER MAIN
BRIDGE PLASMA
TORCH
CONTROL
PCB
AIR
SOLENOID
VALVE
AIR INPUT
AIR SUPPLY
A compressed air supply is required, capable of delivering clean dry air, at a
minimum pressure of 6 Bar, and at a rate of, from 100 to 210 litres per minute,
depending upon the model. (See Specifications on page 2).
Fig. 1