Siemens SIRIUS 3RW52 - Thermistor Motor Protection with Temperature Sensor (Optional)

Functions
8.4 Motor protection
SIRIUS 3RW52 Soft Starter
Equipment Manual, 04/2020, A5E35630451002A/RS-AE/005
139
8.4.2 Thermistor motor protection with temperature sensor (optional)
Operating principle
WARNING
Automatic restart following fault acknowledgment/restart.
Can cause death or serious injury.
The 3RW52 soft starter immediately continues to operate with the values specified by the
control following fault acknowledgment/restart. Outputs are activated when the ON
condition is met.
Take appropriate measures (e.g. start key with monitored start) to prevent unintentional
restarting and to ensure a defined start of the system.
You can connect the temperature sensor of the motor to the 3RW52 soft starter soft starter
and evaluate it. If a specific motor-dependent temperature is exceeded, the
3RW52 soft starter recognizes this and reacts accordingly.
Two different types of measuring sensor can be connected to the 3RW52 soft starter:
Ⴠ PTC thermistors type A
This sensor type is a temperature-dependent resistor.
Ⴠ Thermoclick
This sensor type is a temperature-dependent switch.
When the thermistor motor protection has tripped, the 3RW52 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.
The sensor cables of PTC thermistors type A can be monitored for wire break and
short-circuit.
Additional information
You will find further information on resetting the faults in chapter RESET MODE (Page 105).
You will find more information on the connection of the temperature sensor in chapter
Connecting the temperature sensor (Page 231).