POWER ELECTRONICS
VS65 SERIES MV SOFT STARTER
TECHNICAL CHARACTERISTICS
17
3.1.
Topology
The VS65 soft starter is divided in four sections that isolate the medium voltage from the low voltage
cabinets. The following image shows where the main soft starter components are placed.
Figure 3.1 Inner view- Main components
o
Power stage with SCR modules.
Integrated in antiparallel and connected in series among themselves depending on the rated motor
voltage.
Voltage
Pairs in series
Total SCR
Inverse Peak
Voltage
2300V
1
6
6500V
3300V / 4160V
2
12
13000V
6000V / 6600V
3
18
19500V
o
Snubber Circuit
The soft starter integrates dynamic voltage balanced circuits that protect and balance the current through
the SCR’s.
o
Trigger circuit:
Provides trigger pulses to in order to control the SCR firing. Both the trigger circuit and the SCR are
connected to the medium voltage side and separated from the control board and the transformer by fiber
optics.
o
Line vacuum Contactor:
The line contactor isolate the SCR once the motor is started, increasing the thyristor protection and
lifetime. It will activate when the run sequence command is received by the equipment. When the soft
starter receives the stop command, it will not open the line contactor until the soft starter has stopped the
motor. The status of the contactor can be seen through its dedicated window.
Note: When the customer selects the input module option equipped with circuit breaker, the line
contactor will not be included in the soft starter because its function will be assumed by the circuit
breaker.