Bypass Without Synchronizer (P1260 = 3) - Siemens SINAMICS S150 NEMA Operating Instructions Manual

Functions, monitoring and protective functions
9.4 Extended functions
9.4.2.3

Bypass without synchronizer (p1260 = 3)

Description
When the motor is transferred to the line supply, contactor K1 is opened (after the drive
converter pulses have been inhibited); the system then waits for the motor de-excitation time
and then contactor K2 is closed so that the motor is directly connected to the line supply.
If the motor is connected to the supply in a non-synchronized manner, an equalizing current
flows when the motor is switched in, and this must be taken into account when designing the
protective equipment (see diagram "Circuit example for bypass without synchronization").
Consequently, this bypass type is suitable only for low power drives.
When the motor is being transferred from the supply by the converter, initially contactor K2 is
opened and after the excitation time, contactor K1 is closed. The converter then captures the
rotating motor and the motor is operated on the converter.
This bypass type does not require a VSM10 Voltage Sensing Module.
Contactor K2 must be designed for switching under load.
Contactors K1 and K2 must be interlocked against closing at the same time.
The "flying restart" function must be activated (p1200 = 1).
Figure 9-24
618
Example circuit for bypass without synchronization
Operating Instructions, 12/2018, A5E36652151A
Enclosed Drives