Weld334m - User’s manual
4
1.2
Observations on connections
1.2.1
Earthing, insulation
This paragraph deals with the earthing of the equipment, please ensure that all earthing is
correctly carried out.
•
The correct earthing of each part of the electric system is a compulsory precaution,
in order to ensure the plant workers/operators safety.
•
Furthermore, earthing is of paramount importance to avoid damage to the
installation itself. Periodically check the status of earth connection of all cables and
terminal cards.
•
Special care is to be paid to connections with moving and metal parts, making sure
there is no oxidation of connection and that the electrical connections are made
against painted areas.
•
To have correct earthing, it is fundamental to avoid series connecting the whole earth
installation or part of it with only one cable. It is also important to check that, for
each machine, the earth is star connected at the fixing point of the earth cable.
•
Some types of welding machines need for the earth connection of the transformer
secondary to be made outside of the machine.
•
The Weld334m is a sophisticated, microprocessor controlled equipment which can
also be used in environments showing «electromagnetic field pollution». In the
design phase, systems have been adopted which respect the EMC requirements with
the surrounding ambient. It is recommended to scrupulously observe the conditions
of use (meaning by this that the Weld334m cabinet is to be closed and all its earth
leads must be connected).
•
In compliance with the accident prevention Standards, the welding control does not
act directly on the SCR block; the SCR switching is operated through a special
external firing circuit which is isolated from high voltage present on the power circuit.
1.2.2
Safety criteria against short circuits
On a welding machine, the short circuit is likely to occur on the transformer primary side.
This may entail very serious consequences such as, for example:
•
On a Robot or an automatic installation, the destruction of parts onto which the short
circuit current is discharged.
•
On a manual station, the electrical shock of the operator and damage to the
equipment.
The short circuit may occur between the primary and ground or between the primary and
the secondary.
380/500V
TRS
Robot arm
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