Electronic Trip Unit - Siemens 3VA1 100 A Manual

Description

2.8 Electronic trip unit

2.8 Electronic trip unit
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 sum is more exact
● Evaluation of the current measurement values and constant comparison with the tripping
limits
● Tripping by means of a maglatch
①
②
③
86
Electronic Trip Unit (ETU)
Maglatch
Current sensor
3VA molded case circuit breakers
Manual, 04/2015, A5E03603177010-02