B84, Overvoltage Protection - Siemens SINAMICS DCM Betriebsanleitung

11.7.2

B84, overvoltage protection

Category
Monitoring functions
Function
A SICROWBAR DC overvoltage protection device is installed to protect the power
semiconductors in the field circuit, and is connected to the motor cables to the field circuit.
Overvoltages that occur on the DC side of converters are mainly caused by the field supply
current being suddenly interrupted. This is especially important in the case of a fault (load
trip).
Mode of operation:
If an overvoltage occurs, which reaches the response voltage of the integrated firing module,
then this switches a de-excitation resistor in parallel with the field winding via a thyristor.
The energy stored in the field winding is dissipated through this resistor, therefore limiting the
voltage. Details of the overvoltage protection device as well as information for its selection
are described in Catalog D23.1-2010, Chapter 4.
Note
A supplementary cabinet is required for this option. Depending on the energy in the field
winding, this is either 400 mm or 600 mm wide.
Connection
No additional wiring is required.
SINAMICS DCM Cabinet
Operating Instructions, 04/2015, A5E36161239/RS-AA/001
Options
11.7 Monitoring functions
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