Siemens SENTRON 3WL10 - Page 32

Description
2.6 Possible uses and portfolio
3VA27 molded case circuit breakers & 3WL10 air circuit breakers
30 Manual, 10/2018, L1V30499596002-01
The trip class T
c
specifies the tripping time T
p
for balanced 3-pole loads, starting from the
cold state, with 7.2 times the set current I
r
according to IEC EN 60947 4-1.
The trip classes with "E" stand for a narrower tolerance band of the tripping time T
p
. These
trip classes can also be implemented with the precise electronic trip units of the 3VA27 /
3WL10 motor starter protectors.
The trip class T
c
itself cannot be set directly on the ETU. This can be calculated by
conversion of the delay time t
r
for the I
2
t characteristic to the tripping time T
p
.
Delay time
to be set t
r
:
Corresponds to
tripping time T
p
CLASS T
c
Range
11.5 s 8 s
10A
2 s < T
p
< 10 s
10 4 s < T
p
< 10 s
10E
5 s < T
p
< 10 s
24.5 s 17 s
20
6 s < T
p
< 20 s
20E
10 s < T
p
< 20 s
36 s 25 s
30
9 s < T
p
< 30 s
30E
20 s < T
p
< 30 s
The tripping time T
p
for motor protection has its reference point at 7.2 x Ir while the delay
time t
r
for plant protection has the reference point at 6 x I
r
. For this reason, the delay time t
r
and tripping time T
p
are not identical.