Description
2.8 Electronic trip unit ETU
3VA27 molded case circuit breakers & 3WL10 air circuit breakers
Manual, 10/2018, L1V30499596002-01
73
Protection functions of the ETU
ETU320 LI
ETU350 LSI
ETU360 LSIG
Neutral protection can be enab-
led/disabled
●
●
●
Current setting value I
N
= I
n
x …
0.5; 1; 2
Default value: 0.5
0.5; 1; 2
Default value: 0.5
0.5; 1; 2
Default value: 0.5
G
GF: Ground-fault protection
Protection function can be enab-
led/disabled
—
—
●
Characteristic (switchover possible)
—
—
I²t / t = constant
Default value: I²t
Setting range for operating value I
g
= I
n
x …
(The range <0.2 I
n
or <0.25 I
n
(for
I
n
= 400 A) requires an external auxilia-
ry power supply of the ETU)
—
—
0.1; 0.2; 0.3; 0.4; 0.5;
0.6; 0.7; 0.8; 1
Default value: 0.1
Tolerance
1)
: ± 7%
Setting range for delay time t
g
(fixed)
t=k
—
—
0.1; 0.2; 0.4; 0.6; 0.8 s
Tolerance
1)
: The better
value out of ± 10% or
± 40 ms or 50 ms with
t
g
= instantaneous
Setting range for delay time t
g
at I²t
(reference point 2 x I
g
)
—
—
0.1; 0.2; 0.4; 0.6; 0.8 s
Default value: 0.1 (I²t)
Func-
tions
Frequency adaptation
Setting of the line frequency on ETUs of
the 3-series with DIP switches
50 Hz; 60 Hz
Default value: 50 Hz
50 Hz; 60 Hz
Default value: 50 Hz
50 Hz; 60 Hz
Default value: 50 Hz
1)
ETU powered in at least 2 phases or self-powered with auxiliary voltage. In all other cases,
the following tolerances apply:
Current setting value
Tripping time
L
Tripping between 1.05 and 1.2 x I
r
± 20 %
S
± 10 %
± 20 %
I
± 15 %
≤ 60 ms
G
± 15 %
± 20 %
