Siemens SINAMICS S120 Function Manual page 309

When the line supply returns, the DC link voltage increases again. 5% above the V
switch-on level, the V
normally.
If the power supply is not re-established, the motor speed continues to drop. When the
threshold in p1297 is reached, this results in a response in accordance with p1296.
Once the time threshold (p1295) has elapsed without the line voltage being re-established, a
fault is triggered (F07406), which can be parameterized as required (factory setting: OFF3).
The V
the DC link, by transferring to them a scaling of their speed setpoint from the controlling drive
via BICO interconnection.
Note
If it is expected that the line supply will return, you must make sure that the converter is not
disconnected from the line supply. It could become disconnected, for example, if the line
contactor drops out. The line contactor must be supplied, e.g. from an uninterruptible power
supply (UPS).
Vdc_max control
Figure 6-9
The switch-on level for V
p1294 (automatic sensing of the
ON level (V/f))
Value
= 0
= 1
Drive functions
Function Manual, 11/2017, 6SL3097-4AB00-0BP5
control is switched off again. The motor continues operating
dc_min
controller can be activated for a drive. Other drives can participate in supporting
dc_min
Switching the V
dc_max
dc_max
Meaning
Switched out
Switched in
control on/off
-control (r1282) is calculated as follows:
Switch-on level of the
V control (r1282)
dc_max
r1282 = 1.15 · p0210
r1282 = V - 50 V
dc_max
V/f control (vector control)
6.5 Vdc control
dc_min
Comment
p0210 ≙ device supply voltage
V ≙ overvoltage threshold
dc_max
of the Motor Module
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