Siemens SIRIUS 3RT Series System Manual page 181

The EMC suppression module is available in two versions. The table below shows how the
individual versions of the EMC suppression module differ.
Table 2- 33 Differences between versions of the EMC suppression module
EMC suppression module
RC circuit
Varistor circuit
SIRIUS Innovations
System Manual, 01/2011, A8E56203870002-03
SIRIUS 3RT2 contactors/contactor assemblies
Preferred application
For reducing the rate of rise

For RF attenuation

The values have been selected such that effective interference
suppression can be achieved across a broad spectrum.
The varistor circuit can absorb a high level of energy and can be used
for frequencies ranging from 10 to 400 Hz (controlled operating
mechanisms). There is no limiting below the knee-point voltage.
2.7 Accessories
181