Siemens Sentron 3VA - Electronic trip unit

Description
2.7 Electronic trip unit
3VA molded case circuit breakers with UL and IEC certification
80 Manual, 01/2019, L1V30435333-01
2.7
Electronic trip unit
2.7.1
Electronic trip unit (ETU)
An electronic trip unit is based on the following concepts:
● Complete measurement of the current in the phases L1, L2 and L3, with N and currents
to ground optional
● Rogowski coil
– Very precise measurement of the current
– Better ground-fault protection because the vectorial summation formation is more
exact
● Evaluation of the current measurement values and constant comparison with the tripping
limits
● Tripping by means of a maglatch
①
Electronic trip unit (ETU)
②
Maglatch
③
Current sensor