Bosch PSU 5000 Series Instructions For Assembly And Operation Manual page 92

Circulating currents
When do circulating currents occur?
Supply line
U
V
PE
Supply line
U
V
PE
1070 078 224- -109
PSU 5000 / PSG 3000
Instructions for Assembly and Operation
Circulating currents are defined as currents which do not flow as desired from the
positive pole of the welding equipment through the workpiece and to the negative
pole of the welding equipment during the welding process, but rather through the
workpiece and then through external "ground connections" and the protective con-
ductor jumper (MPE) to the negative pole.
Case 1
Transformer
(
MPE
(
(
Housing
Negative pole grounded through protective conductor jumper (MPE), workpiece
not grounded (ideal arrangement).
Circulating currents are not possible.
Case 2
Transformer
(
MPE
(
(
Housing
Negative pole grounded via protective conductor jumper (MPE), workpiece
grounded, transformer housing insulated from
There will be circulating currents through the mains supply line.
Rectifier +
- -
Rectifier +
- -
.
Connection
Workpiece
Workpiece
11--13