Siemens SENTRON 3VL400 - Functions; Protection functions

3VL IEC molded case circuit breakers
System Manual, 11/2013, 110 0110 - 02 DS 03
35
Functions
4
4.1
Protection functions
4.1.1
Overcurrent release
The 3VL molded case circuit breakers are designed on the principle of magnetic repulsion of
the contacts. The contacts open before the expected peak-value of the short-circuit current is
reached. Magnetic repulsion of the contacts very considerably reduces the thermal load I
2
t
as well as the mechanical load resulting from the impulse short-circuit current I
p
of the
system components that occur during a short-circuit.
(1)
Main connections
(2)
Breaker mechanism
(3)
Overcurrent release
(4)
Movable contact arm
(5)
Arc chute
(6)
Enclosure
Figure 4-1 Interior view MCCB