Protection Functions; Basic Protection Functions; Lt: Overload Protection (Long Time), L-Tripping - Siemens SINOVA Manual

Description
2.2 Electronic components
2.2.5

Protection functions

2.2.5.1

Basic protection functions

The protection functions of the electronic trip unit are available without an additional
auxiliary voltage. The required energy is supplied via current transformers integrated in the
Circuit Breaker.
To evaluate the currents, the RMS value is calculated by the electronic components of the
electronic trip unit.
The individual functions are parameterized by means of rotary coding switches.
Note
Tolerances for the setting currents
L: tripping operations between 1.05 and 1.2 x I
S: - 0 %, + 20 %
I: - 0 %, + 20 %
G: - 0 %, + 20 %
Tolerances for the tripping times
L: - 20 %, + 0 % for I
S: - 0 %, + 60 ms or - 0 %, + 10 % for characteristic with fixed delay time
I: < 50 ms
G: - 0 ms, + 60 ms or - 0 %, + 10 % for characteristic with fixed delay time
2.2.5.2

LT: Overload protection (Long time), L-tripping

The setting value I
can operate without tripping. The time-lag class t
be present without causing a trip.
Setting values for I
ETU350WJ, ETU360WJ
Setting values for t
ETU350WJ, ETU360WJ
The tripping characteristic curve exhibits an I
When the motor protection function is active, a different t
50
t characteristic
2
determines the maximum continuous current at which the Circuit Breaker
R
R
I = (0.4 / 0.45 / 0.5 / 0.55 / 0.6 / 0.65 / 0.7 / 0.8 / 0.9 / 1.0) x I
R
R
t = 10 s (at 6 x I
R
R
determines for how long an overload can
R
)
R
t characteristic.
2
setting applies (see next page).
R
Operating Instructions, 12/2022, L1V30828903001-01
n
3WJ Air Circuit breakers