Current Limitation - Siemens Sentron 3VA Manual

Description
2.3 Technical details
2.3.3

Current limitation

The term "current limitation" refers to the action of limiting the peak value of the prospective
impulse short-circuit current i
The compact design of the breakers has been made possible by their excellent current
limiting capabilities. In the event of a short circuit, the molded case circuit breaker
significantly reduces the magnitude of let-through current, i.e. it reduces the current loading
of downstream equipment (lower thermal load, fewer dynamic forces). The level of let-
through energy is also reduced to a considerable extent.
The 3VA UL molded case circuit breakers are designed as current-limiting molded case
circuit breakers; however, they do not have "current limiting certification" according to
UL 489.
①
②
③
i
D
i
p
t
a
48
p
Unlimited current
Peak value of limited current
Limited current
Let-through current
Unlimited impulse short-circuit current
Break time
to a lower let-through current i
3VA molded case circuit breakers with UL and IEC certification
.
D
Manual, 01/2019, L1V30435333-01