Siemens SINAMICS S120 Manual page 218

Cabinet Modules
5.7 Central Braking Modules
S2 threshold switch
Table 5- 43
Item
1
2
The response threshold at which the Braking Module is activated and the resulting activated
DC link voltage for braking mode are specified in the following table.
The threshold switch must only be switched over when the cabinet unit is disconnected
from the power supply and the DC link capacitors are discharged.
Table 5- 44 Response thresholds of the Braking Module
Rated Response
voltage threshold
380 to 480 774 V
V
673 V
500 to 600 967 V
V
841 V
660 to 690 1158 V
V
1070 V
218
Threshold switch S2
Function
Upper switching threshold (factory setting)
Lower switching threshold
WARNING
Switch Comments
position
1 774 V is the default factory setting. With line voltages of between 380 and 400 V,
the response threshold can be set to 673 V to reduce the voltage stress on the
2
motor and converter. This does, however, reduce the possible braking power
with the square of the voltage (673/774)² = 0.75.
The maximum possible braking power is, therefore, 75%.
1 967 V is the default factory setting. With a line voltage of 500 V, the response
threshold can be set to 841 V to reduce the voltage stress on the motor and
2
converter. This does, however, reduce the possible braking power with the
square of the voltage (841/967)² = 0.75.
The maximum possible braking power is, therefore, 75%.
1 1158 V is the default factory setting. With a line voltage of 660 V, the response
threshold can be set to 1070 V to reduce the voltage stress on the motor and
2
converter. This does, however, reduce the possible braking power with the
square of the voltage (1070/1158)² = 0.85.
The maximum possible braking power is, therefore, 85%.
Cabinet Modules
Manual, (GH5), 05/2010, A5E03263538A