Siemens SENTRON 3VL - 9.2 Overcurrent trip unit with LCD display

Displays and operator controls
9.2 Overcurrent trip unit with LCD display
3VL molded-case circuit breakers
System Manual, 03/2009, 110 0110 - 02 DS 01
125
9.2 Overcurrent trip unit with LCD display
The electronic trip units with LCD display have the following operating features:
● No auxiliary voltage is necessary for the tripping system.
● Current display
● An illuminated green LCD display indicates correct operation of the microprocessor
● Overload status (I > 1.05 x I
R
) is indicated by "overload" on the LCD display
● Direct, user-friendly, menu-driven setting of the absolute values of the protection
parameters in the Ampere values via keys
● Integral self-test function
● Plug-in socket for tester
● Communication link to PROFIBUS DP and Modbus
Electronic trip unit LCD ETU
Characteristic
curve
Application View
L
I
L
S
I
L
I
ETU40 for line 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 memory selectable on/off,
with phase failure sensitivity with ETU40M
(5 to 50% I
R
adjustable)
Short-circuit protection (short-time delay) on
ETU40
I
sd
= 1.5 to 10 x I
R
, t
sd
= 0 to 0.5 s
I
2
t selectable on/off on ETU40
Short-circuit protection (instantaneous)
I
i
= 1.25 to 11 x I
n
(frame-size-dependent)