Siemens SENTRON 3VL series - Page 115

Displays and operator controls
8.2 Overcurrent trip unit with LCD display
3VL IEC molded case circuit breakers
System Manual, 11/2013, 110 0110 - 02 DS 03
115
Electronic trip unit LCD ETU
Characteristic
curve
Application
View
ETU40 for system protection, LI / LSI / LSIN
function,
ETU40M motor / generator protection,
LI
function
Overload protection I
R
= 0.4 to 1 x I
n
,
Trip class t
C
= 5 to 30 at ETU40M
Time-lag class t
R
= 2.5 to 30 at ETU40
Thermal image selectable on / off,
with phase failure sensitivity with ETU40M
(5 ... 50% I
R
adjustable)
"UP" version
Short-circuit protection (short-time delayed) on
ETU40
I
sd
= 1.5 to 10 x I
R
, t
sd
1)
= 0 to 0.5 s
I
2
t selectable on / off on ETU40
"UH" and "UJ" versions
Short-circuit protection (instantaneous)
I
i
= 1.25 to 11 x I
n
(size dependent)
ETU42 for system protection,LSIG/LSING
function
Overload protection I
R
= 0.4 to 1 x I
n
Time-lag class t
R
= 2.5 to 30
Thermal image selectable on/off
Short-circuit protection (short-time delayed)
I
sd
= 1.5 to 10 x I
R
, t
sd
1)
= 0 to 0.5 s
I
2
t selectable on / off
Short-circuit protection (instantaneous)
I
i
= 1.25 to 11 x I
n
(size dependent)
Ground-fault protection:
Measuring method No. 1: (G
R
) vectorial
summation current formation in the three
phases and neutral conductor (4-conductor
systems); I
Δn
= 0.4 to 1 x I
n
, "UL", "UM" and "UN"
versions
Measuring method No. 2: (G
GND
) direct
measurement of the ground-fault current using a
current transformer, I
g
= 0.4 to 1 x I
n
, t
g
= 0.1 to
0.5 s; "UM" version
On 4-pole molded case circuit breakers:
neutral conductor protection N: 50 to 100% I
R
selectable or adjustable.
1)
For t
sd
= 0, the ST function must be set to the value "disabled".