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9 – 11
9.1.5
Protective functions
9.1.5.1 Basic protective functions
The basic protective functions of the trip unit are ensured without additional auxiliary voltage. The required energy is supplied by the
circuit breaker's internal energy transformers.
To evaluate the currents, the electronic system of the trip unit calculates the r.m.s value.
The individual functions are parameterized according to the types via:
- rotary coding switch (ETU745)
- electronic data transfer (ETU776) via:
- TD400 and the software "powerconfig"
- the COM modules with a PC with the software “powerconfig” installed
- the control board (ETU776)
Overload protection – L-tripping
The current setting I
R
defines the maximum continuous current the circuit breaker can carry without tripping. The long-time delay t
R
determines the maximum duration of an overload without tripping.
The tripping characteristic is an I
2
t characteristic. Some trip units can be switched over to an I
4
t characteristic.
Short-time delayed short-circuit tripping – S-tripping
On trip units ETU745 - 776, tripping due to the short-circuit current I
sd
can be delayed by the time t
sd
.
This provides selectivity for short-circuit protection in switchgear with several grading levels.
1)
The delay time 0.02 sec. is not an I
2
t function.
The motor protection function is activated in this position.
2)
For settings t
sd
>0.4 sec., the maximum possible setting I
sd
is reduced automatically according to the frame size:
Frame size I
: 15 kA
Frame size II
: 20 kA
Frame size III : 30 kA
The setting "OFF" for trip units ETU745 and ETU776 is provided to deactivate the short-time delayed short-circuit protection.
If the zone selective interlocking (ZSI)
is used and the ZSI module is set to "S" or "S+G" the adjusted delay time t
sd
is auto-
matically set to 50 ms provided that in the event of short-circuit the circuit breaker does not receive a blocking signal from a downstream
circuit breaker. In this case regardless of the adjusted t
sd
value the circuit breaker will trip after 50 ms.
If a blocking signal exists the adjusted delay time tsd is valid. For safety reasons after 3 s the blocking signal is terminated.
Some trip units can be switched over to an I
2
t-characteristic.
Setting values for I
R
ETU745
I
R
= (0.4 / 0.45 / 0.5 / 0.55 / 0.6 / 0.65 / 0.7 / 0.8 / 0.9 / 1.0) x I
n
ETU776
I
R
= (0.4 - 1.0) x I
n
(given in Amps)
Setting values for t
R
ETU745
t
R
= 2 / 3.5 / 5.5 / 8 / 10 / 14 / 17 / 21 / 25 / 30 sec. (at 6 x I
R
)
ETU776
t
R
= 2 - 30 sec. (at 6 x I
R
)
Setting values for I
sd
ETU745
I
sd
= (1.25 / 1.5 / 2 / 2.5 / 3 / 4 / 6 / 8 / 10 / 12) x I
n
ETU776
I
sd
= 1.25 x I
n
- 0.8 x I
CW
(given in Amps)
Setting values for t
sd
ETU745
t
sd
= 0.02(M)
1)
/ 0.1 / 0.2 / 0.3 / 0.4 sec.; OFF
ETU776
t
sd
= 0.02(M)
1)
/ 0.08 - 4 sec.
2)
; OFF
Содержание UL 489
Страница 36: ...5 21 Frame size II 3000 A Frame size III 1 Holes 14 mm 0720 1 0721_nu ...
Страница 63: ...7 2 Horizontal connectors 0733_nu top view ...
Страница 64: ...7 3 Rear vertical connectors 0734_nu top view rear view ...
Страница 65: ...7 4 Front connectors 0736_nu front view top view ...
Страница 66: ...7 5 Front connectors and pressure wire terminals 0737_nu top view front view ...
Страница 67: ...7 6 7 2 Frame size II fixed mounted version 0494 3_nu ...
Страница 68: ...7 7 Class C always 0494 5_nu top view rear view ...
Страница 69: ...7 8 2500 0738_nu LH side view front view ...
Страница 71: ...7 10 7 4 Frame size III fixed mounted version 0495 1_nu LH side view ...
Страница 72: ...7 11 0495 2_nu top view top view ...
Страница 73: ...7 12 0495 3_nu top view rear view ...
Страница 75: ...7 14 7 5 Door cut outs fixed mounted circuit breaker Frame size I 0735_nu ...
Страница 76: ...7 15 Frame size II III 0496_nu ...
Страница 77: ...7 16 7 6 Frame size I draw out version 0745_nu ...
Страница 78: ...7 17 0746_nu rear view top view ...
Страница 79: ...7 18 0747_nu bottom view ...
Страница 80: ...7 19 0748_nu ...
Страница 81: ...7 20 0749_nu ...
Страница 82: ...7 21 7 7 Frame size II draw out version 0490 1_ul ...
Страница 86: ...7 25 7 8 Frame size III draw out version ...
Страница 87: ...7 26 ...
Страница 88: ...7 27 ...
Страница 89: ...7 28 7 9 Door cut outs for draw out circuit breakers Frame size I 0750_nu ...
Страница 91: ...7 30 7 11 External sensor for neutral conductor WLNCT2 ...
Страница 92: ...7 31 WLNCT3 ...
Страница 107: ...9 5 I tripping Ground fault tripping ...
Страница 256: ...15 12 Installing FS II and FS III 1 Socket head cap screw M5 with washer and nut 1 2 3 4 6 5 7 8 Size 4 5 Nm 45 lb in ...
Страница 307: ...22 2 Installing the door sealing frame Not for use with fuse carriages Catalog No Door sealing frame WLDSF 1 2 3 ...
Страница 351: ......