Siemens Sentron 3VA, Руководство пользователя

Страница: 378 / 492

Accessories
4.12 External current transformer for N conductor
3VA molded case circuit breakers with UL and IEC certification
376
Manual, 01/2019, L1V30435333-01
4.12 External current transformer for N conductor
The external current transformer for N conductor is a current transformer for 3-pole 3VA6
molded case circuit breakers with ETUs 5-series and 8-series. It is used when 3-pole circuit
breakers are to be used in 4-wire systems but monitoring of the N conductor is still desired.
The N conductor is thereby protected against short-circuit and overload.
Available external current transformers for N conductor
N Neutral conductor protection
1)
With rated current I
n
= 40 A: I
N
= 40% … 100% I
n
2)
With rated current I
n
≥ 100 A: I
N
= 20% … 100% I
n
3)
Starting from rated current I
n
≥ 100 A
4)
Dependent on circuit breaker frame size and rated operational current