You can set different tripping characteristics according to the startup class. The higher the class,
the longer the permitted starting time. You can find the graphic for the respective tripping
characteristic at the following link (
https://support.industry.siemens.com/cs/ww/en/ps/25099/
).
8.3.2
Temperature sensor
Operating principle
You can connect the temperature sensor of the motor to the 3RW55 and 3RW55 Failsafe soft
starters and evaluate it. If a specific motor-dependent temperature is exceeded, the 3RW55 or
3RW55 Failsafe soft starter recognizes this and reacts accordingly. You can set the reaction.
2 different types of measuring sensor can be connected to the 3RW55 or 3RW55 Failsafe soft
starter:
• PTC thermistors type A
This sensor type is a temperature-dependent resistor.
• Thermoclick
This sensor type is a temperature-dependent switch.
Note
ATEX / IECEx-certified motor protection
For ATEX / IECEx-certified motor protection, use of the PTC type A sensor only is approved.
The sensor cables of PTC thermistors type A can be monitored for wire break and short-circuit.
You will find more information on the connection of the temperature sensor in chapter
Connecting the temperature sensor (Page 303).
Functions
8.3 Motor protection
SIRIUS 3RW55 and 3RW55 Failsafe Soft Starters
Equipment Manual, 02/2022, A5E35630887002A/RS-AF/006
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