Siemens SENTRON 3VL - Functions; 5.1 Current protection

3VL molded-case circuit breakers
System Manual, 03/2009, 110 0110 - 02 DS 01
41
Functions
5
5.1 Current protection
5.1.1 Overcurrent trip unit
The SENTRON VL 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 significantly reduces the thermal load I
2
t as
well as the mechanical load resulting from the impulse short-circuit current IP of the system
components that occur during a short-circuit.
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(1) Main connections
(2) Breaker mechanism
(3) Overcurrent trip unit
(4) Movable contact arm
(5) Arc chute
(6) Enclosure
Figure 5-1 Interior view MCCB