ESAB LHI 425 Manual Do Usuário E Pecas De Reposicao página 23

The permissible system impedance of the supply, to which the power source is intended to be connected,
shall be equal to or less than 0,0973 Ohm. It is recommended to consult the supply authority in the
evaluation of the actual supply system.
The LHI RECTIFIER is supplied to connect in a 440 V main power supply. In case the power voltage is
different, the primary connections should be modified as indicated in the electric circuit diagram.
Remove the right side lid to have access to make any changes in the voltage, this gives direct access to the
board of primary connections terminal.
The earth terminal is connected to the chassi of the RECTIFIERS. It
should be connected to a efficient earth point of the main power
installation. DO NOT connect the earth conductor of the input cable to
any of the bornes of the ON/OFF switch. This puts the machine chassi
under electric voltage hazard.
All the electric connections should be completely fitted so that there is no risk of sparks, overheating or
drops in the circuit voltage.
N.B.: DO NOT USE THE MAIN POWER NEUTRAL FOR THE
EARTH CONNECTION
6.4)Welding circuit
To guarantee a perfect functioning of the LHI RECTIFIER use a work clamp copper cable, isolated and
with the smallest length possible and compatible with its applications considered, in a well kept state and
firmly fixed to its terminals, also make sure that the connections in the piece to be weld or in the working
station and in the Negative terminal of the set are well fixed.
Any total length (which should be the smallets possible) and any welding current used, the work clamp
cable part should correspond to the maximum current of the LHI RECTIFIER used to supply the duty cycle
of 60%.
The thermal welding circuit causes a drop in the voltage which added to the internal natural drop in the
Rectifier itself, reducing the voltage arc and the maximum current available making the arc unstable.
7) OPERATION
After having the LHI RECTIFIER connected to the main power supply, the electrode holder cable and the
work clamp cable connected:
1) Set the ON/OFF switch to the ON position. The exaustor engine starts to run creating a air flux needed to
cool the machine.
2) Pre-define the welding current throught the potentiometer or the remote control. The potentiometer
rotation clockwise increases the current value, and the rotation anti-clockwise decreases the current
value.
IMPORTANT !
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LHI 425