Welding Circuit - ESAB LHJ 750 User Manual And Spare Parts

Table below gives information for dimensioning cables and line fuses; eventually consult with
local rules.
TABLE 4.1
Feeding
Voltage (V)
220
380
440
LHJ 750 is supplied to operate from a 440V input .In case your input is different, primary
connections must be changed as indicated in the electrical scheme (see page 10). Removal of
left cover primary connections gives direct access to terminal bars of primary connections.
IMPORTANT!
The grounding terminal is connected to the RECTIFIER chassis. It must be
connected to an efficient grounding point of the general power supply system. DO
NOT connect the grounding conductor of the input cable to any of the terminals of
the ON/OFF switch, which would put the machine chassis under electrical tension.
All electrical connections must be firmly tightened to avoid sparking risks, overheating or circuit
voltage drop.
NOTE!
DO NOT USE THE NEUTRAL OF THE POWER SUPPLY SYSTEM FOR
GROUNDING.
4.5

Welding circuit

The good functioning of a LHJ 750 also depends on the use of an insulated copper welding
cable, which must be the shortest possible and compatible to the considered application(s), it
must also be in good shape and firmly connected to its terminals; Electrical connections in the to-
be-welded piece or in the work station and in the set "negative" terminal must be firm.
Whatever the length (the shortest possible) and whatever the used welding current, the welding
cable must correspond to the maximum current which the used RECTIFIER can supply at power
factor 60%.
Welding circuit electrical strength causes voltage drops which add to Rectifier natural internal
drop, reducing the arc voltage and the maximum available current making the arc unstable.
Consume in
nominal load (A)
160
93
80
- 27 -
Feeding
Conductors
(copper - mm²)
35
35
35
Retard
Fuses (A)
160
100
80