Description
2.2 Electronic components
3WJ Air Circuit breakers
52 Operating Instructions, 12/2022, L1V30828903001-01
2.2.5.5 GF: Ground-fault protection (Ground-fault), G-tripping
If the electronic trip unit is equipped with a ground fault protection function, this can protect
consumers against excessive ground fault currents.
Ground fault detection can be implemented by means of vectorial summation of the currents
of the external conductors and N conductor.
In conjunction with the delay time setting t
g, the response value Ig defines the disconnection
of ground faults.
Ig = 100 / 300 / 600 / 900 / 1200 A
tg = 0.1 / 0.2 / 0.3 / 0.4 / 0.5 s
2.2.5.6 N: Neutral conductor protection (Neutral), N-tripping
The ETU360WJ electronic trip unit allows the neutral conductor to be protected against
overload. A current transformer for the neutral conductor (which can be retrofitted if
necessary) is required for this purpose.
With respect to tripping, the same time-lag class t
R applies as for the overload trip.
N
n
2.2.6 Additional functions
Phase-failure protection
When the Circuit Breaker setting is tsd = (0.02s), phase-failure protection is activated.
If the operational current on the phase with the lowest load is 50% less than the operational
current of the phase with the highest load when phase-failure protection is active, the setting
value I
R is automatically reduced to 80%. If the three phase currents do not differ by more
than 50% with respect to each other, the setting value I
R applies.
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