Siemens SENTRON 3WL Reference Manual page 17

3WL Air Circuit Breakers/Non-Automatic Air Circuit Breakers up to 6300 A (AC)
ETU15B solid-state release
Mechanical RESET
for reclosing lockout
and mechanical
tripped indicator
Indicator: overcurrent
release activated
Indicator: overload alarm
Rotary switch for setting
value, overload release
Rotary switch for setting
value, instantaneous
short-circuit release
ETU25B solid-state release
Mechanical RESET
for reclosing lockout
and mechanical
tripped indicator
Indicator: overcurrent
release activated
Indicator: overload alarm
Rating Plug
Rated current module
Rotary switch for setting
value, overload release
Rotary switch for setting
value, instantaneous
short-circuit release
Short-circuit protection
fixed setting
Query pushbutton
Test pushbutton
Option: safety lock
prevents pressing of
reset button after
overcurrent release
Indicator: fault in
overcurrent release
Sealing ring
Test socket
Option: safety lock
prevents pressing of
reset button after
overcurrent release
ETU25B
Indicator: fault in
overcurrent release
Indicator: cause of release
Rotary switch for delay,
short-circuit release
Sealing ring
Clear pushbutton
Test socket
3WL Air Circuit Breakers
Application:
Simple building and
system protection without time-se-
lective coordination up to 4000 A.
Not to be used for size III.
Features:
• Adjustable overload protection
I 2
with t characteristic curve
with preset delay time
t = 10 seconds at 6 ×
I R
R
• Instantaneous short-circuit pro-
tection adjustable in the range
2 ... 8 ×
I n
• Overload display
• Protection function is set by
means of the rotary coding
switch
For technical details see the table
"Functional overview of the
solid-state release system"
under "Technical specifications".
Application:
Classical building, motor and sys-
tem protection with time-selective
coordination for up to 6300 A
Features:
• Adjustable overload protection
I 2
with t characteristic curve
Delay time t =
R
10 seconds at 6 ×
I R
• Short-time delayed short-circuit
protection adjustable in the
range 1.25 ... 12 × and
I n
• Instantaneous short-circuit
protection preset
to 20 × , max. 50 kA
I n
• Can be adapted at any time to
the required plant currents
through retrofittable rated cur-
rent module, thus ensuring over-
load protection in the range from
100 A to 6300 A
• Overload display
• Indicates the reason for tripping
by means of an LED
• Test facility for the release
• Protection functions are
set by means of the
rotary coding switch
For technical details see the table
"Functional overview of the
solid-state release system"
under "Technical specifications".
General data
Siemens · 2009 17