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Efficient Networks Siemens Sinamics S120 User Manual

Page 162

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Vector control

4.20 Bypass

Drive Functions

162

Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4

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Figure 4-26 Signal diagram, bypass with synchronization with overlap

The motor is transferred to the line supply

(the drive converter controls contactors K1 and K2):
● The initial state is as follows: Contactor K1 is closed, contactor K2 is open and the motor

is fed from the drive converter.

● The control bit "bypass command" (p1266) is set (e.g. from the higher-level automation).
● The bypass function sets the control word bit "synchronizing" (r1261.2).
● Since the bit is set while the converter is running, the "Transfer motor to supply"

synchronization process is started.

● After the motor has been synchronized to the line frequency, line voltage and line phase,

the synchronizing algorithm reports this status (r3819.2).

● The bypass mechanism evaluates this signal and closes contactor K2 (r1261.1 = 1). The

signal is internally evaluated - BICO wiring is not required.

● After contactor K2 has signaled back the "closed" state (r1269[1] = 1), contactor K1 is

opened and the drive converter inhibits the pulses. The drive converter is in the "hot

standby" state.

● If the on command is withdrawn in this phase, the drive converter changes into the basic

standby state. If the appropriate contactors are being used, the drive converter is isolated

from the line supply and the DC link is discharged.

Retrieving the motor from supply mode functions the same but in reverse:

At the start of the process, contactor K2 is closed and contactor K1 is opened.
● The "Command bypass" control bit is canceled (e.g. by the higher-level automation).
● The bypass function sets the control word bit "synchronizing".