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Transfer of motor to the line supply
(contactors K1 and K2 are controlled by the converter):
● The initial state is as follows: Contactor K1 is closed, contactor K2 is open and the motor
is fed from the converter.
● The control bit "bypass command" (p1266) is set (e.g. by 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 line supply"
synchronization process is started.
● The synchronizing algorithm signals once the motor has been synchronized to the line
frequency, line voltage and phase position (r3819.2).
● The bypass mechanism evaluates this signal and closes contactor K2 (r1261.1 = 1). The
signal is evaluated internally - BICO wiring is not required.
● After contactor K2 has signaled back the "closed" state (r1269[1] = 1), contactor K1 is
opened and the drive inhibits the pulses. The converter is in "Ready for operation and
bypass" state.
● If the On command is cancelled in this phase, the converter will change to "Ready to start
and bypass" state. 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.
● The "Bypass command" control bit is canceled (e.g. by the higher-level automation).
● The bypass function sets the control word bit "synchronizing".
● 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.
● The synchronizing algorithm signals once the converter has been synchronized to the line
frequency, line voltage and line phase.
● The bypass mechanism evaluates this signal and closes contactor K1. The signal is
evaluated internally - BICO wiring is not required.
● Once contactor K1 has reported "closed" state, contactor K2 is opened and the motor
returns to operation on the converter.
Enclosed Drives
Operating Instructions, 12/2018, A5E36652151A
Functions, monitoring and protective functions
9.4 Extended functions
615
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