Breaking Capacity - Siemens 3VA1 100 A Manual

Description
2.3 Technical details
Double-rotary contact system
To achieve excellent current limiting, the 3VA molded case circuit breakers are equipped
with a double-rotatory contact system that opens dynamically on its own above the specified
disengaging currents on the principle of magnetic repulsion before the expected peak value
of the short-circuit current is reached. These limits have been coordinated and optimized to
suit the overall device characteristics. This substantially reduces the thermal and mechanical
loading on the molded case circuit breaker and the electrical installation.
①
②
③
The switching pole cassettes are optimized for high breaking capacity, and their double-
rotary contact system design enables extremely good current limiting thanks to the build-up
of peak arc voltage generated at both contacts in the event of a short-circuit. This results in
significant limitation of the let-through energy I²t and the let-through current.
2.3.6

Breaking capacity

The rated ultimate short-circuit breaking capacity I
current which the protective device is capable of disconnecting in accordance with
regulations. Up to this value, the protective device is also allowed to be used in a network.
The new 3VA molded case circuit breakers are available with identical external dimensions
but various breaking capacity classes according to size and rated operational current range.
54
Fixed contacts
Rotary contact system
Arc splitter chute
is the maximum value of the short-circuit
cu
3VA molded case circuit breakers
Manual, 04/2015, A5E03603177010-02