Intrinsic Device Protection (3Rw40 Only) - Siemens SIRIUS 3RW30 Manual

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.
Recovery time (thermistor motor protection)
If the thermistor motor protection is tripped, the soft starter cannot be restarted until the
sensor installed in the motor has cooled down. The recovery time varies according to the
temperature state of the sensor.
5.3.2

Intrinsic device protection (3RW40 only)

Thyristor protection (thermal)
SIRIUS 3RW40 soft starters are equipped with integrated intrinsic device protection to
prevent thermal overloading of the thyristors.
This is achieved on the one hand by means of current measuring transformers in the three
phases and on the other, by measuring the temperature with temperature sensors on the
thyristor's heat sink.
If the fixed, internally set trip value is exceeded, the soft starter is automatically disconnected.
Recovery time (intrinsic device protection)
If the intrinsic device protection is tripped, the soft starter cannot be restarted until a recovery
time of at least 30 seconds has elapsed.
SIRIUS 3RW30 / 3RW40
Manual, 01/2010, 535 1995-02 DS01
5.3 Motor protection / intrinsic device protection (3RW40 only)
Functions
35