Bypass With Synchronizer Without Degree Of Overlapping (P1260 = 2) - Siemens SINAMICS G150 Operating Instructions Manual

9.3.2.2

Bypass with synchronizer without degree of overlapping (p1260 = 2)

Description
When "Bypass with synchronizer without degree of overlapping (p1260 = 2)" is activated,
contactor K2 (to be closed) is only closed when contactor K1 is opened (anticipatory type
synchronization). During this time, the motor is not connected to a line supply so that its
speed is determined by the load and the friction. The phase position of the motor voltage
before synchronization must be set to establish a "lead" before the line supply to which the
system should be synchronized. This is realized by setting the synchronization setpoint
(p3809). A phase and frequency difference of around zero is produced when closing
contactor K2 by braking the motor in the brief period in which both contactors are open.
For the function to run correctly, the moment of inertia of the drive and the load must be
sufficiently high.
Note
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. The
electrical angular difference of the motor relative to the phase difference of the line supply
may only change to the extent that it can still be compensated using p3809.
It is no longer necessary to use the de-coupling reactor after having determined the
synchronizing setpoint (p3809) in the manner described above.
Figure 9-14
Converter cabinet units
Operating Instructions, 03/2012, A5E03263466A
K 1
M
~
Example circuit for bypass with synchronizer without degree of overlapping
Functions, Monitoring, and Protective Functions
K 2
9.3 Extended functions
485