Siemens SENTRON 3VA2 - Page 162

Applications
3.3 Motor protection applications of 3VA molded case circuit breakers
3VA molded case circuit breakers with IEC certificate
160 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
The ETU550M has a permanently activated thermal memory.
Short-time delayed short-circuit protection S:
•
I
sd
Adjustable from 1.2 to 12/15 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
sd
Permanently set to 0.03 s
Instantaneous short-circuit protection I:
•
I
i
Adjustable from 3 to 12/15 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
Trip class T
c
or tripping time T
p
:
•
T
c
Adjustable 10 A / 10E / 20 / 20E / 30
•
T
p
Adjustable from 3 to 13 / 15 / 25 / 30 s (dependent on rated current)
in steps of 1 s
Phase unbalance I
unbal
•
I
unbal
Adjustable from 5 to 50% relative to the
mean value of the three phase currents
in steps of 1%
•
t
unbal
tripping time
1)
during startup Adjustable from 0.7 to 60 s,
default setting 0.7 s
•
t
unbal
tripping time
1)
during normal operation Adjustable from 4 to 420 s,
default setting 4 s
The phase unbalance function can be deactivated.
1)
Adjustable tripping time with phase unbalance in firmware version 4.3 and higher.