Safety Standards; Explosion And Fire Prevention; Safety Of Operator And Third Parties; General Definition - Air Liquide CEMONT PRATIKA 211 AC/DC Instruction De Securite D'emploi Et D'entretien

EN
The technical specifications and the wiring diagrams contained in
this user manual are valid only for the model system which has the
serial number indicated on the sticker.
TRANSFORMERS FOR MANUAL ARC WELDING WITH LIMIT-
ED DUTY CYCLE
1.0

SAFETY STANDARDS

The use of welding equipment and the execution of welding oper-
ations place both the operator and others at risk. It is the opera-
tor's duty to read, assimilate and observe the safety regulations
indicated below. It is worth remembering that a prudent operator
familiar with and observant of the relative safety regulations, is the
best safeguard against accidents. Before connecting, preparing,
using or transporting the transformer, carefully read the safety
regulations indicated below.
1.1

EXPLOSION AND FIRE PREVENTION

Incandescent slag and sparks may cause fires. Fires and explo-
sions are dangers, which can be avoided following the regulations
indicated below:
- Clear or protect, using fire-retardant material, flammable
substances and objects such as wood, sawdust, clothing,
paints, solvents, petrol, kerosene, natural gas, acetylene,
propane and any other flammable substance.
- Even if the recipient or pipe to be welded is open, empty and
thoroughly clean the welding operation must nonetheless be
executed with due care.
- Always make sure that a fire extinguisher, sand or water etc.
is at hand as a fire-fighting measure.
1.2

SAFETY OF OPERATOR AND THIRD PARTIES

Since welding is a source of radiation, loud noise, heat and toxic
gaseous fumes, the safety of the operator and third parties must
be guaranteed by appropriate safety measures. Never expose
yourself to the action of the electrical arc or incandescent metal
without wearing the necessary protective clothing. Disregard of
the regulations indicated below when carrying out welding opera-
tions, may cause serious damage to your health.
- Always wear suitable protective clothing, i.e.: non-flamma-
ble heavy gauntlet-type gloves, thick shirt with long sleeves,
trousers without turn-ups, ankle-high boots to protect the skin
from arc rays, sparks or incandescent metal, and hard hat or
welder's cap to protect hair.
- Always wear a mask with special protection filter (at least
NR10 protection or more) to protect the eyes. Also take care
to protect the face, ears and neck. Notify those in the vicinity
to keep well clear of the range of arc rays and incandescent
metal. Always use ear protectors. Welding operations can be
noisy and may even disturb others working in the vicinity.
- Always wear safety glasses with side shields, particularly
when removing slag either manually or mechanically. Slag is
generally very hot in temperature and may throw sparks
some considerable distance. Notify work colleagues in the vi-
cinity when removing such material.
- Cordon off the welding area with a fireproof partition, since
rays, sparks, incandescent slag may injure colleagues or per-
sons in the vicinity of the welding area.
2.0

GENERAL DEFINITION

The welding unit provides a smooth electrical arc in order to weld
two metal parts together. In fact, the electrical arc struck between
the electrode and welding joint, generates such a high tempera-
ture that it melts both the electrode and base metal. The molten
metal droplets which form the electrode are deposited on the
welding joint, thereby creating a molten metal poor which welds
the joint as it solidifies. The electric we/ding unit primarily compris-
es a metal or plastic housing which contains the transformer. It is
the transformer which serves to reduce the line voltage to one that
is suitable and harmless (50 to 70 V). This voltage which is avail-
able at the transformer output generates a flow of electrons and a
SAFETY STANDARDS
corresponding high electric current (50÷160 AMP) each time the
welding electrode contacts the piece to be welded. The welding
unit is fitted with a device which regulates the current (1 - Picture
1 Page 3.) supplied by the transformer. A control scale (2 - Picture
1 Page 3.) indicates the current setting. This device optimises the
welding current in accordance with the electrode diameter. The
starter switch (3 - Picture 1 Page 3.) which is usually located on
the panel interrupts the primary supply line (i.e.: 230 V/400V).
Picture 1.
3
1
3
1
Some welding units may be supplied by two different voltages,
which are selected using the starter switch. The indicator lights on
the welding unit indicate THERMOSTAT tripped.
2.1

OPERATION PARAMETERS

The table printed on the generator indicates the operation param-
eters which are expressed in number of electrodes and which are
as follows:
nc: indicates the number of reference electrodes the generator
can weld starting at ambient temperature before the thermostat is
tripped; nh: indicates the average number of reference electrodes
which can be welded between thermostat resetting and tripping;
nh1: represents the total number of reference electrodes which
can be welded in an hour starting with the generator at ambient
temperature; nh1: presents the total number of reference elec-
trodes which can be welded in an hour after the first thermostat re-
set.
2.2

THERMOSTATIC PROTECTION

A thermostatic protection (thermostat) is fitted on the transformer
to protect the windings from overheating (in heavy duty welding
applications). If the windings exceed a predetermined tempera-
ture threshold, which might damage the insulation, the thermostat
3 EN
2
2