User Manual

Functions
5.3 Motor protection / intrinsic device protection (3RW40 only)
SIRIUS 3RW30 / 3RW40
36 Manual, 10/2010, 535199502000 DS 03
Trip class (electronic overload protection)
The trip class (CLASS) specifies the maximum time within which a protective device must
trip from a cold state at 7.2 x the rated operational current (motor protection to IEC 60947).
The tripping characteristics represent this time as a function of the tripping current (refer to
chapter Motor protection tripping characteristi
cs for 3RW40 (with sy
mmetry) (Page 168)).
You can set different CLASS characteristics according to the startup class.
Note
The rated data of the soft starters refers to normal starting (CLASS 10). The starters may
need to be calculated with a size allowance for heavy-duty starting (> CLASS 10). You can
only set a rated motor current that is lower than the soft starter rated current (for the
permissible settings, refer to chapter Technical data (Page 127)).
Recovery time (motor overload protection)
A recovery time of 5 minutes, during which the motor cools down and cannot be restarted,
starts if the thermal motor model is tripped.
Protection against voltage failure in the event of a fault
If the control supply voltage fails during a trip, the current tripping state of the thermal motor
model and the current recovery time are stored in the soft starter. When the control supply
voltage is restored, the current tripping state of the thermal motor model and the intrinsic
device protection prior to the power failure are likewise automatically restored. If the control
voltage is disconnected during operation (without a preceding fault trip), the starter is not
protected against voltage failure.
Temperature sensor
Note
Temperature sensor
The temperature sensor evaluation function is optionally available for the SIRIUS 3RW40 24
to 3RW40 47 soft starters in the 24 V AC/DC control voltage version.
This motor protection function measures the motor's stator winding temperature directly with
the help of a sensor installed in the motor, in other words the motor must have a sensor
wound into the stator winding.
You can choose between two different sensor types for the evaluation.
1. Type A PTC thermistors ("type A sensors") for connection to terminals T11/21 and T12
2. Thermoclick sensors for connection to terminals T11/21 and T22
The wiring and sensors are monitored for wire breakage and short-circuits.