OPERATIONS AND MAKING ELECTRICAL CONNECTIONS,
Connecting the cutting current return cable.
ALWAYS MAKE SURE THAT THE PLASMA CUTTING SYSTEM HAS
Connect the cutting current return cable to the piece to be cut or to the
BEEN SWITCHED OFF AND DISCONNECTED FROM THE MAIN
metal support bench, taking the following precautions:
- Make sure there is a good electrical contact, especially when cutting
POWER SUPPLY.
sheet that has an insulated coating or is oxidised etc.
ELECTRICAL CONNECTIONS MUST BE CARRIED OUT ONLY AND
- Make the earth connection as close as possible to the cutting area.
EXCLUSIVELY BY ESPERT OR SKILLED TECHNICIANS.
- Using metal structures that are not part of the workpiece as the cutting
________________________________________________________
current return conductor may endanger safety and result in an
inadequate cut.
PREPARATION
- Do not make the earth connection to the part of the piece that is to be
Unpack the machine, assemble the separate parts supplied with the
cut away.
package.
Connecting the plasma cutting torch (FIG. H) (where provided).
Assembling the return cable-earth clamp (Fig. E)
Insert the male terminal of the torch into the centralised connector on the
front panel of the machine, matching the polarisation key. Tighten the
HOW TO LIFT THE MACHINE
locking ring nut, clockwise as far as it will go, to ensure air and current
All the machines described in this manual must be lifted using the handle
passage with no leaks.
or the sling provided with the machine, if the model has one (fitted as
For some models the supplied torch is already connected to the power
shown in FIG. F).
source.
IMPORTANT!
POSITIONING THE MACHINE:
Before starting a cutting operation, make sure the consumable parts
The machine must be installed in a place where there are no obstructions
have been fitted correctly by inspecting the head of the torch, as
to the cooling air input and output apertures; at the same time, make sure
described in the chapter on "TORCH MAINTENANCE".
that there is no possibility of conductive powder, corrosive vapour or
moisture etc. being sucked into the machine.
6. PLASMA CUTTING: DESCRIPTION OF THE PROCEDURE
Allow at least 250 mm of free space all around the machine.
The plasma arc and the application principle in plasma cutting.
________________________________________________________
Plasma is a gas that is heated to an extremely high temperature and is
ionised so that it becomes an electrical conductor. This cutting procedure
WARNING! Prevent the machine from tipping up or shifting
uses the plasma to transfer the electric arc to the metal piece that is
dangerously, by positioning it on a level surface that is able to
melted by the heat and hence separated. The torch uses compressed air
support its weight.
form a single source, for both the plasma gas and the cooling and
________________________________________________________
protection gas.
HF strike
CONNECTION TO THE MAIN POWER SUPPLY
This type of strike is normally used on models with currents of over 50A.
- Before making any electrical connection whatsoever, check the power
Cycle start is determined by a high frequency/high voltage (“HF”) arc that
source rating plate to make sure that the mains voltage and frequency
is used to strike a pilot arc between the electrode (-ve polarity) and the
correspond with those at the place where the machine is to be
torch nozzle (+ve polarity). When the torch is brought close to the piece to
installed.
be cut, which is connected to the (+) polarity of the power source, the pilot
- The power source must be connected only and exclusively to a power
arc is transferred to set up a plasma arc between the electrode (-) and the
supply system with a neutral conductor connected to earth.
piece itself (the cutting arc): The pilot arc and HF strike are disabled as
- In order to guarantee protection against indirect contact use RCD's of
soon as the plasma arc is established between the electrode and the
the following types:
piece.
Pilot arc hold time is set in the factory at 2 s; if there is no arc transfer
- Type A (
) for single phase machines;
within this time the cycle is automatically stopped, apart from the
continuance of cooling air.
- Type B (
) for 3-phase machines.
To re-start the cycle it is necessary to release the torch button and then
press it again.
- In order to satisfy the requirements of Standard EN 61000-3-11
(Flicker) we recommend connecting the power source to power supply
Shorting strike
interface points with an impedance of less than the values shown in
This type of strike is normally used on models with currents of less than
table 1 (TAB.1).
50A.
Cycle start is determined by movement of the electrode inside the torch
nozzle, which is used to strike a pilot arc between the electrode (-ve
Plug and socket
polarity) and the nozzle itself (+ve polarity).
- Single phase models with absorbed currents no greater than 16A are
When the torch is brought close to the piece to be cut, which is connected
supplied with a power supply cable with a standard plug (2P+T) 16A
to the (+) polarity of the power source, the pilot arc is transferred to set up
\250V.
a plasma arc between the electrode (-) and the piece itself (the cutting
- Single phase model with absorbed currents greater than 16A and 3-
arc):
phase models have power supply cables that are to be connected to
The pilot arc is disabled as soon as the plasma arc is established
standard plugs, (2P+T) for single phase models and (3P+T) for 3-
between the electrode and the piece.
phase models, with appropriate capacities. Prepare a mains outlet
fitted with a fuse or an automatic circuit-breaker; the corresponding
Pilot arc hold time is set in the factory at 2 s; if there is no arc transfer
earth terminal must be connected to the (yellow-green) earth
within this time the cycle is automatically stopped, apart from the
conductor for the main power supply.
continuance of cooling air.
- Table 1 (TAB. 1) shows the recommended sizes for the delayed fuses
To re-start the cycle it is necessary to release the torch button and then
on the power supply line, calculated according to the max. nominal
press it again.
output current of the machine, and to the rated power supply voltage.
________________________________________________________
Preliminary operations.
Before starting cutting operations, make sure the consumable parts have
been fitted correctly by inspecting the head of the torch, as described in
WARNING! Failure to comply with the above rules will
the chapter on "TORCH MAINTENANCE".
render the manufacturer’s (class I) safety system ineffective, with
- Switch on the power source and set the cutting current (FIG. C-1),
consequent serious risks to people (e.g. electric shock) and to
basing it on the thickness and type of the metal that is to be cut. TAB. 3
property (e.g. fire).
shows the cutting rate for various thicknesses of aluminium, iron and
________________________________________________________
steel.
- Press and release the torch button so that there is an outflow of air (
CUTTING CIRCUIT CONNECTIONS
³
30 seconds of post-air).
________________________________________________________
- During this period, adjust the air pressure until the reading on the
pressure gauge corresponds to the required value in “bar” for the
WARNING! BEFORE MAKING THE FOLLOWING
particular torch being used (TAB. 2).
- Operate the air button so that the air flows out of the torch.
CONNECTIONS MAKE SURE THAT THE POWER SOURCE HAS
- Adjust the knob: pull upwards to release it and turn it to adjust the
BEEN SWITCHED OFF AND DISCONNECTED FROM THE MAIN
pressure to the value given in the TECHNICAL INFORMATION
POWER SUPPLY.
ABOUT THE TORCH.
Table 1 (TAB. 1) shows the recommended values for the return cable (in
2
- When the required reading (bar) is shown on the pressure gauge,
mm ), based on the maximum current output from the machine.
press the knob to lock the pressure at the adjusted value.
________________________________________________________
- Allow the last air to flow out naturally in order to facilitate removal of any
condensation that may have formed inside the torch.
Compressed air hookup (FIG. G).
Important:
- Prepare a compressed air distribution line with minimum pressure and
- Contact cut (with torch nozzle in contact with piece being cut): this can
capacity as given in table 2 (TAB. 2), for those models where it is
be applied with a max current of 40-50A (higher current values will
provided.
immediately destroy the nozzle-electrode-nozzle holder).
IMPORTANT!
- Space cutting (with a spacer mounted on the torch, FIG. I): this can be
Do not exceed the maximum input pressure of 8 bar. Air containing
applied for currents of over 35A;
substantial quantities of moisture or oil may cause excessive wear on the
- Extended nozzle and electrode: this can be applied where provided
consumable parts or damage the torch. If the quality of the available
for.
compressed air is doubtful, we recommend using an air dryer, to be fitted
upstream of the input filter. Use a flexible pipe to connect the compressed
Cutting operations (FIG. L).
air supply to the machine, fitting one of the supplied connectors to the
- Bring the torch nozzle close to the edge of the piece (at about 2 mm),
input air filter on the back of the machine.
press the torch button; after about 1 second (pre-air) the pilot arc will
strike.
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