Siemens SIRIUS 3RW30 Manual page 33

The two types of protection must be combined to achieve full motor protection. This
combination is recommended to protect the motor optimally.
Note
Thermistor motor protection evaluation
The thermistor motor protection evaluation function is optionally available for the SIRIUS
3RW40 2 to 3RW40 4 soft starters in the 24 V AC/DC control voltage version.
Motor overload protection
The current flow during motor operation is measured by measuring the current with
transformers integrated in the soft starter. The temperature rise in the winding is calculated
based on the rated operational current set for the motor.
A trip is generated by the soft starter when the characteristic is reached, depending on the trip
class (CLASS setting).
ATEX
"Increased safety" type of protection EEx e acc. to ATEX Directive 94/9/EC
The SIRIUS 3RW40 soft starter sizes S0 to S12 are suitable for starting explosion-proof
motors with the "increased safety" type of protection EEx e (type of protection / marking: Ex II
(2) GD).
Wire the fault output (95 96) to an upstream switching device in such a way that if a fault
occurs, this device disconnects the feeder (refer to Fig. "3RW40 wiring fault with 3RV").
Figure 5-5
SIRIUS 3RW30 / 3RW40
Manual, 01/2010, 535 1995-02 DS01
5.3 Motor protection / intrinsic device protection (3RW40 only)
3RW40 wiring fault
Functions
33