Functions
7.7 ATEX / IECEx-certified motor overload protection
SIRIUS 3RW50 soft starter
Manual, 09/2019, A5E35628455002A/RS-AA/001
133
7.7
ATEX / IECEx-certified motor overload protection
Environmental conditions
Comply with the ambient conditions for which the 3RW50 soft starter is approved.
Note
Ambient temperature during operation.
Note that the 3RW50 soft starters are approved for operation in a temperature range of
-25 °C to +60 °C.
In ambient temperatures higher than 40 °C, take the derating of the rated operational current
into consideration.
You can find further information on derating in the Technical specifications (Page 193) in the
section "Power electronics" or in Catalog IC 10
https://support.industry.siemens.com/cs/ww/en/view/109747945
Note
Temperature sensor
For ATEX / IECEx-certified motor protection, use of the PTC type A sensor only is approved.
Note
Simulation Tool for Soft Starters
Note that the Simulation Tool for Soft Starters (Page 23) already takes into account the
derating for certain ambient temperatures when selecting a suitable 3RW5 soft starter.
Parameterizing the soft starter
The parameters for ATEX / IECEx applications are to be set using the setting elements of
the 3RW50 soft starter.
Setting the rated motor operational current
Set the 3RW50 soft starter to the rated operational current of the motor as stated on the type
plate or design test certificate of the motor.
Tripping class (electronic overload protection)
Make sure that the motor and the cables are dimensioned for the selected tripping class.
Note that the trip class "CLASS OFF" when operating motors in hazardous areas is only
permissible if a "PTC thermistor type A" temperature sensor is used.
The rated data of the 3RW5 soft starter relates to normal starting (CLASS 10E). For heavy
starting (> CLASS 10E), you may have to overdimension the 3RW5 soft starter.
