General Information; Installation; Location; Main Supply Voltage Requirements - Helvi PC75 Manual De Uso

PLASMA ARC AND BASIC PRINCIPLES
FOR THE PERFORMANCE OF PLASMA
CUTTING
• Plasma is a gas that is heated to an extremely
high temperature and ionised so that it beco-
mes a conductor of electricity.
• This cutting procedure utilises the plasma to
transfer the electric arc to the metal workpie-
ce, which is melted by the heatand then sepa-
rated.
• The torch uses compressed air from a single
source, for both the plasma and cooling and
protective gas.
• The start of the cycle is determided by an arc,

LOCATION

Be sure to locate the welder according
to the following guidelines.
• In areas, free from moisture and dust;
• Ambient temperature between 0° to 40°C;
• In areas, free from oil, steam and corrosive
gases;
• In areas, not subjected to abnormal vibration
or shock;
• In areas, not exposed to direct sunlight or rain;
• Make sure that obstacles do not prevent the
cooling air flow out of front and rear ope-
nings of the machine.
• Arrange an open space of at least 5m around
the machine.
• In the case the machine has to be moved,
always disconnect the plug from the outlet
and gather the cables and pipes so as not to
damage them.
Since the inhalation of welding fumes
can be harmful, ensure that the welding
area is effectively ventilated.

MAIN SUPPLY VOLTAGE REQUIREMENTS

Before you make any electrical connection,
check that supply voltage and frequency avai-
lable at site are those stated in the ratings la-
bel of your generator.
The main supply voltage should be within ±10% of
the rated main supply voltage. Too low a voltage
may cause poor welding performance. Too high a
supply voltage will cause components to overheat
and possibly fail. The welder Power Source must be:
• Correctly installed, if necessary, by a qualified
electrician;
• Correctly grounded (electrically) in accordan-
ce with local regulations;
• Connected to the correct size electric circuit.
In case the supply cable is not fitted with a plug,
connect a standardized plug (3P+T) to the
cable (in some models the supply cable is supplied
with plug).
EN-6

GENERAL INFORMATION

INSTALLATION

supply
called the pilot arc, which is struck between
the mobile electode(negative polarity) ab
dthe torch nozzle (positive polarity) due to the
short circuit between these two elements.
• When the torch is brought into direct contact
with the workpiece to be cut (connetcted to
the positive polarity of the power source) the
pilot arc is transfered between the electrode
and the workpiece itself thus striking a pla-
sma arc, also called cutting arc.
• The duration of the pilot arc is set in the fat-
cory at 3 seconds; if the transfer has not been
made within this time, the cycle is automati-
cally stopped except for the cooling air which
is kept on.
To connect the plug to the supply cable, follow these
instructions:
• the brown (phase) wire must be connected to
the terminal identified by the letter L1
• the blue or grey wire must be connected to
the terminal identified by the letter L2
• the black or grey wire must be connected to
the terminal identified by the letter L3
• the yellow/green (ground) wire must be con-
nected to the terminal identified by the letter
PE or by the symbol
In any case, the connection of the yellow/green wire
to the PE terminal
the event of tearing of the power supply cable from
the plug, the yellow/green wire should be the last
one to be disconnected.
The outlet should be protected by the proper
protection fuses or automatic switches.
Notes:
• Periodically inspect supply cable for any
cracks or exposed wires. If it is not in good
conditions, have it repaired by a Service Cen-
tre.
• Do not pull violently the input power cable to
disconnect it from supply.
• Do not squash the supply cable with other ma-
chines, it could be damaged and cause electric
shock.
• Keep the supply cable away from heat sorces,
oils, solvents or sharp edges.
• In case you are using an extension cord, try to
keep it well straight and avoid its heating up.

SAFETY INSTRUCTIONS

For your safety, before connecting the power source
to the line, closely follow these instructions:
• An adequate switch must be inserted before
the mains outlet; this switch must be equip-
ped with time-delay fuses;
• The connection with ground must be made
with a plug compatible with the above men-
tioned socket;
.
must be done in order that in