Pre-Charging And Bypass Contactor Chassis And Chassis-2 - Siemens SINAMICS S120 Function Manual

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3.5 Pre-charging and bypass contactor Chassis and Chassis-2

3.5 Pre-charging and bypass contactor Chassis and Chassis-2
Function description
Pre-charging is the term for the procedure used to charge the DC link capacitors via resistors.
Pre-charging is carried out from the feeding supply network. The precharging input circuit limits
the charging current of the DC link capacitors.
● Chassis format
The pre-charging input circuit for Active Infeed and Smart Infeed Modules consists of a pre-
charge contactor with pre-charging resistors and a bypass contactor. The
Active Line Module controls the pre-charging input circuit in the Active Interface Module
through terminals.
● Chassis-2 format
The pre-charging and main contactor must be provided externally for
Active Interface Modules. The control and feedback of the switches required for operation
are implemented and monitored using the software of the Active Line Modules. The
necessary signal interconnections are described in the manual referred to below: Opening
and closing times of the contacts being used can be adjusted using parameter p0255
(power unit contactor monitoring time).
● Sizes FI, GI, HI and JI
The precharging input circuit in the Active Interface Module of module types FI and GI
contains the bypass contactor. The bypass contactor must be provided separately for frame
sizes HI and JI.
● Smart Line Module
With the Smart Line Module, precharging is integrated in the Smart Line Module itself. The
bypass contactor must be implemented in this case.
● Basic Line Modules (Thyristor)
For Basic Line Modules with thyristors, the built-in thyristors are connected instead of a
bypass contactor. For Basic Line Modules with diodes, the bypass contactor is implemented
as a circuit breaker.
Further information
You will find more detailed information in the following manual:
● SINAMICS S120 Manual for Chassis Power Units, Air-cooled
Procedure during switch-on
● The precharging contactor is closed and the DC link is charged via the precharging resistors.
● Once precharging is complete, the bypass contactor is closed and the precharging
contactor opened. The DC link is precharged and ready for operation. If precharging could
not be completed, fault F06000 is output.
Procedure during switch-off
● The pulses are inhibited and the bypass contactor is then opened.
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Function Manual, 06/2019, 6SL3097-5AB00-0BP2
Drive functions