Bypass - Siemens Sinamics S120 Function Manual

Vector control

4.25 Bypass

Preconditions
● Only possible for identical chassis power units connected in parallel
● Maximum number of parallel power units is 4
● Parallel connection of power units with suitable power reserves
● DRIVE-CLiQ star topology (possibly a DMC20 or a DME20, refer to the GH1 manual)
● Motor with one single-winding system (p7003 = 0)
● No Safe Torque Off (STO)
Overview of important parameters (see SINAMICS S120/S150 List Manual)
● p0125 Activate/deactivate power unit component
● r0126 Power unit component active/inactive
● p0895 BI: Activate/deactivate power unit component
● p7003 Par_circuit winding system
4.25 Bypass
Features
● Available for the vector control mode
● Available for induction motors without encoder
Description
The bypass function controls two contactors via digital outputs of the drive converter and
evaluates the feedback signals of the contactors via digital inputs (e.g. via TM31). This circuit
allows the motor to either be fed from the drive converter or connected directly to the supply
line. The drive converter controls the contactors; the feedback signals for the contactor
states must be fed back to the drive converter.
This bypass circuit can be implemented in two ways:
● Without synchronizing the motor to the line supply and
● Synchronizing the motor to the line supply.
For all bypass versions, the following applies:
● The bypass is always switched-out when one of the control word signals "OFF2" or
● Exception:
204
"OFF3" is withdrawn.
When required, the bypass switch can be interlocked by a higher-level control so that the
drive converter can be completely powered-down (i.e. including the control electronics)
while the motor is operated from the line supply. The contactor interlocking should be
implemented on the plant/system side.
Function Manual, (FH1), 01/2012, 6SL3097-4AB00-0BP2
Drive functions