Siemens SIRIUS 3RT Series System Manual page 129

Design
The contactors are supplied as complete units with integrated coil electronics and are fitted
as standard with varistors for damping opening surges in the coil. The opening delay is
consequently 2 ms to 5 ms longer than for standard contactors.
Note
Auxiliary switch blocks are fitted on contactors with an electronic drive in the same way as on
basic versions.
Mounting instruction
These contactor versions of size S0 are approved for side-by-side mounting at ambient
temperatures of up to 70 °C.
Coupling relays for railway applications (sizes S00 and S0)
These contactors have an extended operating range of 0.7 to 1.25 x U
Design
The magnet coils of the contactor relays and motor contactors with an extended operating
range in size S00 are connected to suppressor diodes (3RT20..-2K, 3RT2017-2K.4). The
magnet coils of the motor contactors with an extended operating range in size S0 are
connected to varistors (3RT202.-2K.40). No additional series resistor is required in either
case.
Note
Coupling relays for railway applications cannot be expanded by means of auxiliary switch
blocks.
Mounting instruction
A clearance of 10 mm must be observed when using side-by-side mounting at an ambient
temperature > 60 °C < 70 °C.
SIRIUS Innovations
System Manual, 01/2011, A8E56203870002-03
SIRIUS 3RT2 contactors/contactor assemblies
2.4 Configuration
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S
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