Functions
5.1 Current protection
3VL molded-case circuit breakers
42 System Manual, 03/2009, 110 0110 - 02 DS 01
The circuit breaker as an overload current tripping system
1. Overcurrent trip unit of the SENTRON VL160X to VL630 circuit breaker, thermomagnetic, TM.
The overcurrent trip unit and short-circuit release work with bimetals and magnetic coils.
They are available with fixed settings or adjustable.
The 4-pole circuit breakers for system protection can be supplied with overcurrent trip units
in all 4 poles or without an overcurrent trip unit in the 4th pole (N). From 100 A, the trip units
in the 4th pole (N) can be set to 60% of the current in the 3 main current paths, so that safe
protection of the neutral conductor can be guaranteed with a reduced cross-section.
The circuit breakers for starter combination applications are usually combined with motor
contactor and suitable overload relays.
The non-automatic circuit breakers have integrated self-protection against short-circuit so
that back-up fuses can be omitted. These circuit breakers have no overload protection.
Four-pole circuit breakers have no short-circuit release in the 4th pole (N).
To Next Page
Loading...
