ESAB LAF Series User Manual

-12-
hga7d3ea
4 Connection in Parallel Using Six-Thyristor Operation
In this case the Master/Slave welding power sources are connected to the mains by
way of six thyristors (three in each welding power source). T his results in softer
welding current as the phase shift is 60° instead of 120° .
S Connection of Master+Slave using the six-thyristor effect. Note that the primary
winding of the Slave is reversed.
S The phase shift goes down from 120° to 60 ° , see the diagrams below.
S The following sine-wave diagram shows the equalising effect obtained when
using inversion of the Slave transformer.
The requirement is that the welding power sources are of the same size, and that it
is possible to shift the input and output on the primary side of the main transformer.
This is easily done on LAF 1001, 1251 and 1601, whereas it is more complicated on
LAF 631, as the winding of the transformer is connected directly to the main
contactor.
GB

ESAB LAF Series Specifications

General

Duty Cycle	100% at rated current (depending on model)
Input Frequency	50/60 Hz
Current Range	30-500 A
Input Voltage	380-415V/440-460V
Output Current Range	30-500 A
Efficiency	85%
Cooling	Water-cooled (depending on model)
Power Factor	0.93