Smart Infeed - Siemens SINAMICS G130 Engineering Manual

The following precharging contactors are recommended:
SIRIUS 3RT1034 for one precharging resistor per phase and SIRIUS 3RT1044 for two precharging resistors
connected in parallel per phase.
The fuse protection for the precharging circuit of S120 Basic Line Modules in Chassis format must be provided
externally by the customer. The fuses recommended for this purpose are listed in the table below.
Owing to the brief period of overlap when the precharging contactor and the bypass contactor are closed at the same
time, it is essential to ensure that the precharging circuit has the same phase sequence as the main circuit.
S120 Basic Line Modules in Cabinet Modules format are equipped as standard with one precharging resistor per
line phase, as illustrated in the diagram above. Two resistors connected in parallel per line phase in order to increase
the permissible DC link capacitance of the drive configuration (see section "Checking the maximum DC link
capacitance") are available on request.
The precharging circuit of S120 Basic Line Modules in Cabinet Modules format is protected as standard by fuses
integrated in the Line Connection Module LCM which is connected in series upstream of the Basic Line Module.
The following table specifies the rms values of the line currents which occur at the beginning of the precharging
process in the case of line supply voltages 400 V or 690 V. Due to the principle of precharging using resistors, the
specified values apply irrespective of the DC link capacitance to be precharged. Where other line voltage values
apply, the line currents must be converted in proportion to the line voltage.
The specified precharging currents decay according to an e-function until the precharging process is completed after
a period of typically 1 to 2 s. Due to the temperature rise in the precharging resistors during the process, the
minimum permissible interval for complete precharging of the DC link is 3 minutes.
S120 BLM output
at
400 V or 690 V
Frame size Output
380 V – 480 V 3AC
GD 900 kW
GD 900 kW
500 V – 690 V 3AC
GD 1500 kW
GD 1500 kW
S120 diode-based Basic Line Modules: Line currents at the beginning of precharging (initial rms values)
6.5.2

Smart Infeed

In the case of SINAMICS S120 Smart Line Modules, which are available as air-cooled units only in S120 Chassis and
S120 Cabinet Modules formats, the DC link is precharged by a precharging circuit with resistors, a process which
incurs heat losses. To precharge the DC link, the rectifier is connected at the line side to the line supply via a
precharging contactor and precharging resistors. Once the DC link is precharged, the bypass contactor is closed and
the precharging contactor opened again.
Input current Precharging
at resistance value
400 V or 690 V per phase
1630 A
(1 resistor per phase)
1630 A (2 parallel-connected
resistors per phase)
1580 A
(1 resistor per phase)
1580 A (2 parallel-connected
resistors per phase)
Line current at the
beginning of precharging
(initial rms value)
400 V or 690 V
2.2 Ω
1.1 Ω
4.0 Ω
2.0 Ω
SINAMICS Engineering Manual – November 2015
SINAMICS S120
Engineering Information
Recommended
fuses (provided
externally) to
at protect
precharging arm
on S120 Chassis
91 A 3NE1 817-0 (50 A)
182 A 3NE1 021-0 (100 A)
86 A 3NE1 817-0 (50 A)
172 A 3NE1 021-0 (100 A)
Ó Siemens AG
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