Device functions
7.6 Motor protection functions
3RW44 soft starters
138 Manual, 03/2017, NEB535219502000/RS-AB/008
The idle time can be set between 1 and 100 s.
Motor protection in accordance with IEC 60947 (CLASS 10A, 10, 15, 20, 30) is no longer
provided if the idle time is changed (0 = deactivated). This means that there will be no
system protection in such cases. Parallel protective measures are recommended.
The motor must be designed for such inching operation as otherwise permanent damage
may arise due to overload.
A recovery time, during which the motor cools down and cannot be restarted, starts if the
thermal motor model is tripped.
Protection against voltage failure
If protection against voltage failure is activated, and 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 prior to the power failure is likewise automatically restored.
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. PTC thermistors Type A ("type A sensors")
2. Thermoclick sensors
The wiring and the sensors are checked for wire breakage and short-circuits.
Note
If the soft starter is switched off via a motor protection or inherent device protection tripping,
the action cannot be acknowledged using the "Trip
Reset" function until the displayed
cooling time has expired.
To Next Page
Loading...
Need help?
General
