Efficient Networks Siemens Sinamics S120 - Manual (Page 163)

Vector control
4.20 Bypass
Drive Functions
Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4
163
● Pulses are enabled. Since "Synchronize" is set before "Pulse enable", the converter
interprets this as a command to retrieve a motor from the supply and to take it over.
● After the motor has been synchronized to the line frequency, line voltage and line phase,
the synchronizing algorithm reports this status.
● The bypass mechanism evaluates this signal and closes contactor K1. The signal is
internally evaluated - BICO wiring is not required.
● Once contactor K1 has reported "closed" status, contactor K2 is opened and the motor is
operated again on the converter.
4.20.2 Bypass with synchronization, without overlap (p1260 = 2)
Description
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).
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.
Sufficiently large moment of inertia is a precondition for sound functioning.
It is no longer necessary to use the de-coupling reactor after having determined the
synchronizing setpoint (p3809).
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Figure 4-27 Circuit example, bypass with synchronization without overlap
Activating
The bypass function with synchronization without overlap (p1260 = 2) can only be activated
using a control signal. It cannot be activated using a speed threshold or a fault.