Siemens SENTRON 3VL160X System Manual page 55

Application example:
If the molded case circuit breaker is equipped with an undervoltage release, and the leading
auxiliary switch is installed in the rotary operating mechanism, the leading NO contacts make
it possible to supply the undervoltage release with power before the main contacts can be
closed.
Leading auxiliary switch for switching off (leading NC contact)
Application example:
In applications with thyristors, it is necessary to reset the power electronics of the converter
before the main circuit is switched off.
Molded case circuit breakers with leading auxiliary switches create a leading signal that
enables selective deceleration of the thyristor.
3VL IEC molded case circuit breakers
System Manual, 11/2013, 110 0110 - 02 DS 03
Functions
4.2 Internal accessories
55