3WL Air Circuit Breakers
3WL Air Circuit Breakers/Non-Automatic Air Circuit Breakers up to 6300 A (AC)
Project planning aids
34
Siemens · 2009
■
Characteristic curves
Every solid-state release type and every setting has its own cha-
racteristic curve. Only a selection is shown in the following. The
characteristic curves each show the largest and smallest setting
range of SENTRON 3WL circuit breakers with 1000 A rated cur-
rent at 500 V rated voltage with various releases. In order to ob-
tain a complete tripping characteristic, the relevant parts of the
characteristics have to be combined.
The characteristic curves show the behavior of the solid-state re-
lease when it is activated by a current that is already flowing be-
fore the tripping operation. If the overcurrent tripping occurs im-
mediately after switch on and the solid-state release is therefore
not yet enabled, the opening time is extended, depending on the
level of the overcurrent by up to 15 ms. In order to determine the
break-times of the circuit breakers, approximately 15 ms must
be added to the opening times shown for the arcing time.
2)
Refer to the following legend for tolerances.
The characteristic curves shown apply to ambient temperatures
at the circuit breaker between –5 and +55 °C. The release can
be operated at ambient temperatures of –20 to +70 °C. An ex-
tended tolerance band can apply at these temperatures.
SENTRON 3WL circuit breaker with ETU25B solid-state release,
LSI characteristic curve
SENTRON 3WL circuit breaker with ETU27B solid-state release,
G characteristic curve
Tolerances for the set currents
L: tripping operations between 1.05 and 1.2 x I
R
S: –0 %, +20 %
I: –0 %, +20 %
G: –0 %, +20 %
Tolerances for the tripping times
L: –20 %, +0 % for I
2
t characteristic curve
S: –0 %, +60 ms or -0 %, 10 % for tripping times greater than 600 ms
I: < 50 ms
G: –0 %, +60 ms or -0 %, 10 % for tripping times greater than 600 ms
SENTRON 3WL circuit breaker with ETU15B solid-state release
SENTRON 3WL circuit breaker with ETU27B solid-state release,
LSIN characteristic curve
SENTRON 3WL circuit breaker with ETU45B solid-state release,
S characteristic curve
1) Sizes I and II: 100 ... 1200 A
Size III: 400 ... 1200 A.
2) With single-pole loading in the lowest rated current range, the response
times of the short-circuit release can be extended by approx. 10 % and
the tripping times by approx. 15 % compared to the characteristic curve.
0,01
0,1
1
10
100
1000
10000
0,1
1 10 100
NSE0_01520
[s]
/
n
R
min
R
max
0,4 ... 1,0 x
n
sd
min
1,25 ... 12 x
n
0 ... 0,4 s
sd
max
sd
max
sd
min
i
> 20 x
n
max. 50 kA
i
Opening time
0,01
0,1
1
10
100
1000
10000
100
1000 10000 100000
NSE0_01521
[s]
g
min
g
max
100 ... 1200 A
1)
0,1 ... 0,5 s
g
max
g
min
A
Opening time
0,01
0,1
1
10
100
1000
10000
0,1
1 10 100
NSE0_01527
[s]
/
n
i
min
i
max
R
min
R
max
0,5 ... 1,0 x
n
2 ... 8 x
n
Opening time
0,01
0,1
1
10
100
1000
10000
0,1
1 10 100
NSE0_01519
[s]
/
n
R
min
R
max
0,4 ... 1,0 x
n
N
sd
min
1,25 ... 12 x
n
0 ... 0,4 s
sd
max
sd
max
sd
min
i
> 20 x
n
max. 50 kA
i
Opening time
0,01
0,1
1
10
100
1000
10000
0,1
1 10 100
NSE0_01523
[s]
sd
0,1 ... 0,4 s
/
n
2
sd
= const
1,25 ... 12 x
n
2
sd
= const
sd
= const
0,02 ... 0,4 s
Opening time
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