ESAB LAB 320, Instruction Manual, Page: 21 / 52

NOTE: DO NOT USE THE NEUTRAL OF THE POWER SUPPLY SYSTEM FOR
GROUNDING.
IMPORTANT !
The grounding terminal is connected to the 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 voltage.
All electrical connections must be firmly tightened to avoid sparkling risks, overheating or circuit voltage
drop.
LAB 320
LAB 475
21
The LAB 320 and 475 Sources are supplied for connection to a power main of 440 V. In case the power
voltage is different, the primary connections should be modified as indicated in the electric diagrams
(Appendix A). The right side panel can be removed to gain direct access to the terminal bar to the primary
connections.
TABLE 6.1
LAB 320
LAB 475
Model
220
220
380
380
440
440
Feeding
voltage
(V)
30
17
15
46
26
23
Consumption in
rated loading
(A)
10
10
10
10
10
10
Feeding
conductors
(copper – mm²)
40
30
25
65
40
35
Delayed
fuses
(A)
6.4) Welding circuit
The good performance of a LAB Source depends on the usage of a copper “Work” cable, isolated, and with
the smallest length possible and compatible with the considered application(s), and in good trim, tightly
fixed in its terminals, and still, the connections in the piece to be weld, or in the working station and in the
“negative” terminal of the set should all be correctly fixed.
Regardless of its total length (which should be the smallest possible) and regardless of the welding current
used, the part of the “Work” cable should correspond to the maximum current that the unit uses to supply in
the duty cycle of 100%.
The electric resistor of the welding circuit causes drops in the voltage which added to the natural internal
slopes of the rectifier itself, decreases the arc voltage and the maximum current available making the arc
unstable.
accordingly (see table 6.1).
For the electric feeding of a LAB Source, the User can use the inlet cable supplied or a proper cable with the
corresponding gauge to the desired length, and always with 4 conductors, that being 3 feeding conductors