Bypass With Synchronization Without Overlap - Siemens SINAMICS S120 Function Manual

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Bypass with synchronization without overlap

When "bypass with synchronization without overlap (p1260 = 2)" is activated, contactor K2 to

be closed is only closed when contactor K1 has opened (anticipatory type synchronization).

During this time, the motor is not connected to the line supply so that its speed is determined

by the load and the friction. Phasing of the motor voltage before synchronization must be set

such that there is an "initial jump" upstream of the supply to which synchronization should be

carried out. This is done by setting the synchronization setpoint (p3809). As a result of the

motor braking in the short time during which, both contactors are open, when closing

contactor K2, a phase and frequency difference of approximately zero is obtained.

For the function to run correctly, the moment of inertia of the drive and the load must be

A sufficiently high moment of inertia is characterized by a change in the motor speed during

opening of the contactors K1 and K2 that is approximately equal to the rated slip. The

electrical angle difference of the motor relative to the phase difference of the line supply may

only change to the extent that it can be compensated using p3809.

It is no longer necessary to use the decoupling reactor after having determined the

synchronizing setpoint (p3809).

The bypass function with synchronization without overlap (p1260 = 2) can only be activated

using a control signal. Activation using a speed threshold or a fault is not possible.

Drive functions

Function Manual, (FH1), 01/2013, 6SL3097-4AB00-0BP3

Circuit example, bypass with synchronization without overlap

Vector control