Siemens SINAMICS G150 Operating Instructions Manual page 557

For the function to run correctly, the moment of inertia of the drive and the load must be
sufficiently high.
Note
Sufficiently high moment of inertia
A sufficiently high moment of inertia is characterized by a change in the motor speed when
contactors K1 and K2 are opened, which is approximately equal to the rated slip. Further, it
must be ensured that at the switchover instant, the motor is not significantly braked as a
result of external effects (e.g. friction).
It is no longer necessary to use the de-coupling reactor after having determined the
synchronizing setpoint (p3809) in the manner described above.
Figure 9-17
Activation
The synchronized bypass without overlap (p1260 = 2) function can only be activated using a
control signal. It cannot be activated using a speed threshold.
Converter cabinet units
Operating Instructions, 07/2016, A5E03347396A
Example circuit for bypass with synchronizer without degree of overlapping
Functions, monitoring, and protective functions
9.3 Extended functions
557