Functions, monitoring, and protective functions
9.4 Extended functions
Drive converter cabinet units
344
Operating Instructions, 07/07, A5E00288214A
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Once motor synchronization to line frequency, line voltage and line phasing is complete,
the synchronization algorithm reports this state (r3819.2).
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The bypass mechanism evaluates this signal and closes contactor K2 (r1261.1 = 1). The
signal is evaluated internally - BICO wiring is not required.
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After contactor K2 has fed back the "closed" state (r1269[1] = 1), contactor K1 is opened
and the converter inhibits the pulses. The converter is in "Ready for operation and
bypass" state.
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If the On command is cancelled in this phase, the converter will change to "Ready to start
and bypass" status. If the appropriate contactors are being used, the converter will be
isolated from the line supply and the DC link discharged.
To transfer the motor back from the line supply, the sequence is simply reversed: At the start
of the process, contactor K2 is closed and contactor K1 is open.
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The "Command bypass" control bit is canceled (e.g., by the higher-level automation).
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The bypass function sets the control word bit "synchronizing".
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The pulses are enabled. Since "synchronizing" is set before "pulse enable", the converter
interprets this as a command to retrieve the motor from the line supply.
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Once converter synchronization to line frequency, line voltage and line phasing is
complete, the synchronization algorithm reports this state.
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The bypass mechanism evaluates this signal and closes contactor K1. The signal is
evaluated internally - BICO wiring is not required.
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Once contactor K1 has reported "closed" status, contactor K2 is opened and the motor
returns to operation on the converter.
9.4.2.2
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). 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 done 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.
In order for the function to run correctly, the moment of inertia must be sufficient.
Due to the expense of determining the synchronization setpoint (p3809), the decoupling
restrictor is not needed.
The "flying restart" function must be activated (p1200 = 1).