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ALFA
IN
a.s.
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www.alfain.eu
Make sure that the earthing system of the electric equipment is correctly
connected and operational.
The operator must be insulated from the metal components connected to the
return wire.
The earthing of the piece being worked could increase the risk of injury to the
operator.
EN 60974-1 Standard: Open-circuit voltage. During the operation of the
machine, the highest voltage, with which it is possible to come into contact, is
the open-circuit voltage between the welding clamps.
The maximum open-circuit voltage of the welding machines is established by
national and international standards (EN 60974-1) depending on the type of
weld current to be used, on its waveform and on the hazards arising from the
work place. These values are not applicable to the strike currents and those for
stabilisation of the arc that could be above it.
The open-circuit voltage, for as many adjustments as possible, must never
exceed the values relating to the various cases shown in the following table:
Case Working
conditions
Open-circuit
voltage
1
Places with increased risk of
electric shock
DC current: 113V
peak value
AC current: 68V
peak value and
48V effective
2
Places without increased risk
of electric shock
DC current: 113V
peak value
AC current: 113V
peak value and
80V effective
3 Torches
held
mechanically
with increased protection for
the operator
DC current: 141V
peak value
AC current: 141V
peak value and
100V effective
In case 1, the dc welding machines with rectifier must be built in such a way
that, in case of a fault developing in the rectifier (for example open circuit, short
circuit or lack of power), the permitted values cannot be exceeded.
Before opening the machine switch off the machine and disconnect it from the
power socket.
Only personnel authorised by this company can carry out maintenance on the
machine.
3 ELECTROMAGNETIC
COMPATIBILITY
(EMC)
This welding machine conforms to EN 60974-10 standard. However, the
electromagnetic emissions generated could prove not be compatible with the
maximum permitted levels for some classes of electrical equipment, such as
the following:
Domestic electronic appliances (radios, TVs, videos, telephones, burglar
alarms, etc.).
Computers, robots, electro-medical instruments and life-support systems.
Radio-television transmitters and receivers.
Pacemakers and hearing aids.
All very sensitive electrical equipment.
