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Parameters
and
can take on the following
values according to the curve selected.
• Normal inverse time-delay curve (NI):
= 0.02
= 0.14.
• Very inverse time-delay curve (VI):
= 1
= 13.5.
• Extremely inverse time-delay curve EI):
= 2
= 80.
Selection of t> trip time
The trip time of the protection is adjusted by using
the Dip Switches as shown in the figure.
By means of the Dip Switches, the value of K is set
which, when replaced in the previous relation-
ships, determines trip time t>.
The following settings are possible:
• 16 trip times (t>),
(K = 0.1...1.6 with steps of 0.1)
0.1
0.2
0.3
0.4
0.6
0.7
0.8
0.9
1.1
1.2
1.3
1.4
1
2
3
Caption
1 Dip Switch for setting the trip threshold of protection
I>
2 Dip Switch for setting timing K of protection I>
3 Dip Switch for selecting the type of curve for
protection I>:
• DT curve with definite time
• NI curve with normal inverse time
• VI curve with very inverse time
• EI curve with extremely inverse time.
Protection against instantaneous or
delayed short-circuit (50)
This function makes a family of definite adjustable
time curves available, indicated by the symbol I>>.
The corresponding trip time is indicated by the
symbol t>>.
Start of timing is signalled by the ALARM LED
lighting up, whereas circuit-breaker opening is
signalled on the front by the magnetic flag I> I>>,
turned to the yellow position. To reset signalling,
the FLAG RESET pushbutton on the front of the
release must be pressed, ensuring one of the
following conditions:
a) 24 Vdc auxiliary voltage present (display lit);
b) primary circulating current higher than 0.2 x In
(display lit with indication of the circulating
current);
c) application of the TT2 unit to the TEST connec-
tor on the front of the release (optional acces-
sory).
0.5
1.0
Selection of I>> threshold value
1.5
1.6
Setting the I>> threshold is carried out by working
on the Dip Switches as shown in the figure below.
The sum of the values selected represents the
multiple of I> and corresponds to threshold I>>.
N.B. Even if protection I> is OFF, the first Dip Switch
takes on the value 0.2.
The following settings are possible:
• 16 threshold current values (I>>)
2.5
7.5
12
17
OFF
3.5
4.5
5.5
8.5
9.5
10.5
13
14
15
18
19
20
3
x I>
13
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