3WL air circuit breakers
3.1 Introduction and overview
3WL/3VL circuit breakers with communication capability - PROFIBUS
System Manual, 03/2011, A5E01051353-02
29
3.1.3
Function overview of the overcurrent tripping system
Table 3- 1
Function overview of the tripping system of the ETU
Basic function
ETU45B
ETU76B
Overload protection
✓
✓
Function can be switched off/off
–
✓
Adjustment range I
R
= I
n
× ...
0,4-0,45-0,5-0,55-0,6-0,
65-0,7-0,8- 0,9-1
0,4...1
Switchable overload protection
(I
2
t or I
4
t-dependent function)
✓
✓
Adjustment range time-lag class t
R
at 6 × I
R
for I
2
t
2-3.5-5.5-8-10-14-17-21-25-
30 s
2...30 s
Adjustment range time-lag class t
R
at 6 × I
R
for I
4
t
1-2-3-4-5 s
1...5 s
Thermal memory can be switched
on/off
✓
✓
Phase loss sensitivity
at t
sd
= 20 ms (M)
✓ (on/off)
N-conductor protection
✓
✓
Function can be switched on/off
✓
✓
N-conductor adjustment range I
N
= I
n
× ...
0,5...1
0,2...2
Short-time delayed short-circuit
protection
✓
✓
Function can be switched on/off
✓
✓
Adjustment range I
sd
= I
n
× ...
1,25-1,5-2-2,5-3-4- 6-8-10-12
1.25 x I
n
...0.8 x I
cw
Adjustment range delay time t
sd
M-100-200-300-400 ms
M-80...4000 ms
Switchable short-time delayed short-
circuit protection (I
2
t-dependent
function)
✓
✓
Adjustment range delay time t
sd
at I
2
t
100-200-300-400 ms
100...400 ms
ZSI function
Per CubicleBUS module
Per CubicleBUS module
,
1
16(D
Instantaneous short-circuit protection
✓
✓
Function can be switched on/off
✓
✓
Adjustment range I
i
= I
n
× ...
1.5-2.2-3-4-6-8-10-12 x I
cs
1.5 x I
n
...0.8 x I
cs
Ground-fault protection
Retrofittable module
Retrofittable module
Tripping and alarm functions
✓
✓
Tripping function can be switched
on/off
✓
✓
Alarm function can be switched
on/off
–
✓
