SINAMICS G150
Engineering Information
SINAMICS Engineering Manual – November 2015
Ó Siemens AG
323/528
5.8 Load-side components and cables
5.8.1 Motor reactors
The fast switching of the IGBTs in the inverter causes high voltage rate-of-rise dv/dt at the inverter output. If long
motor cables are used, these voltage gradients increase the current load on the converter output due to capacitive
charge/discharge currents. The length of cable which may be connected is therefore limited.
The high voltage rate-of-rise and the resulting voltage spikes at the motor terminals, increase the voltage stress at
the motor winding in comparison to direct line operation. The motor reactors (option L08) reduce the capacitive
charge/discharge currents in the motor supply cables and limit the voltage rate-of-rise dv/dt at the motor terminals
according to the motor cable length.
For a more detailed description, please refer to the section "Motor reactors" of the chapter "Fundamental Principles
and System Description".
5.8.2 dv/dt filters plus VPL and dv/dt filters compact plus VPL
The dv/dt filter plus VPL (option L10) and the dv/dt filter compact plus VPL (option L07) comprise two components,
the dv/dt reactor and the voltage limiting network (Voltage Peak Limiter), which limits voltage peaks and returns the
energy back to the DC link.
The dv/dt filter plus VPL and the dv/dt filter compact plus VPL must be used when the dielectric strength of the
insulation system on the motor to be connected is unknown or inadequate. Siemens standard and trans-standard
asynchronous motors generally require a filter (depending on the motor range) only with line supply voltages of
> 460 V or > 500 V in cases where no special insulation is provided on the motor side. Further information can be
found in chapter "Motors".
The dv/dt filter plus VPL limits the voltage rate-of-rise to values < 500 V/µs and the typical voltage spikes at the motor
to the values below:
· V
PP
(typically) < 1000 V for V
Line
< 575 V
· V
PP
(typically) < 1250 V for 660 V < V
Line
< 690 V
The dv/dt filter compact plus VPL limits the voltage rate-of-rise to values of < 1600 V/ms and the typical voltage spikes
on the motor to the following values:
· V
PP
(typically) < 1150 V for V
Line
< 575 V
· V
PP
(typically) < 1400 V for 660 V < V
Line
< 690 V
For a more detailed description, please refer to section "dv/dt filters plus VPL and dv/dt filters compact plus VPL" in
chapter "Fundamental Principles and System Description".
5.8.3 Sine-wave filters
Sine-wave filters (option L15) are LC low-pass filters and constitute the most sophisticated filter solution. They are
significantly more effective than dv/dt filters in reducing the voltage rates-of-rise dv/dt and peak voltages V
PP
, but
operation with sine-wave filters imposes substantial restrictions in terms of the possible pulse frequency settings and
voltage and current utilization of the motor-side inverter (voltage and current derating).
For a more detailed description and for the derating data, please refer to the section "Sine-wave filters" of the chapter
"Fundamental Principles and System Description".
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