Siemens SENTRON 3VA2 - Page 136

Applications
3.2 Line protection applications of 3VA molded case circuit breakers
3VA molded case circuit breakers with IEC certificate
134 Manual, 03/2019, A5E03603177010-03
Overload protection L:
•
I
r
Adjustable from 0.4 to 1.0 x I
n
in absolute current values
I
r
< 50 A: in steps of 0.5 A
I
r
≥ 50 A: in steps of 1 A
•
t
r
Adjustable from 0.5 to 12 / 15 / 17 / 20 / 25 s (dependent on rated operational
current and frame size)
with a reference point of 6 x I
r
.
In steps of 0.1 s
The ETU550 LSI and ETU850 LSI units have a thermal memory; this can be deactivated.
Short-time delayed short-circuit protection S:
•
I
sd
Adjustable from 0.6 to 9 / 10 x I
n
I
sd
< 50 A: in steps of 0.5 A
I
sd
≥ 50 A: in steps of 1 A
•
t
sd
Adjustable from 0.05 to 0.5 s
with a reference point of I
sd
= 8 x I
r
in steps of 0.01 s
The curve shape I
2
t = constant can be deactivated.
Instantaneous short-circuit protection I:
•
I
i
Sizes 100 A to 400 A:
adjustable from 1.5 to 10 / 12 x I
n
Size 630 A:
See tables above
in steps of 1 A
Neutral conductor protection N:
The neutral conductor protection function is available only for 3-pole molded case circuit
breakers with external current transformer for N conductor for 4-pole molded case circuit
breakers.
•
I
N
Adjustable in steps of 1 A
3-pole
breakers with external current transformer for N conductor:
I
n
< 63 A: 0.4 to 1.6 x I
n
I
n
≥ 63 A: 0.2 to 1.6 x I
n
4-pole
breakers:
I
n
< 63 A: 0.4 to 1.6 x I
n
I
n
≥ 63 A: 0.2 to 1.0 or 1.6 x I
n