Bosch PST 6101.321 Technical Information page 25

System
Welding current
50/60 Hz
Frequency
f
20 ms
1000 Hz Frequency
f
1 ms
Figure 3: Comparison of 50/60 Hz and 1000 Hz welding
1-4
PST 6101.321 / PSI 6101.321
A 50 Hz welding system uses an AC welding current with gaps. The half-sines are set by
the thyristor unit in scale values (%I) between 0 to 99, corresponding to an electrical angle
of 31° to 130°.
The welding current can be controlled by the closed-loop constant-current regulation
system (KSR) integrated in the weld timers.
The Bosch medium-frequency welding system uses DC current for welding. The duration
of the welding current is programmed in milliseconds (ms). The welding process is per-
formed more evenly. The range of good welds is increased.
The medium-frequency welding current is clocked at 1000 Hz. The constant-current reg-
ulation system is faster and more precise compared to 50/60 Hz welding.
U
t
U
t
Output voltage of the
thyristor unit
t
Output voltage of the
inverter
t
Welding current
I
Welding current
I
1070 080 056-101 (99.09) GB
t
t