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NVA100X-D - Manual - 02 - 2016
FUNCTION CHARACTERISTICS
The second element may be blocked by means of the Cold Load Pickup (CLP)
[1]
function.
If the CLP function is enabled the element is blocked for an adjustable time interval, starting from the
starting control criterion (circuit breaker closure or I
RUN
threshold).
The CLP Activation time parameter (tLRCLP>>) may be adjusted inside the Set \ Profi le A(or B) \
Locked rotor - 50S/ 51LR/14\ ILR>> Element \ Setpoints menu.
Starting control
If the CLP Source parameter is set to IRUN and the maximum value of phase currents is lower than
0.1 I
B
, the protection is blocked off.
If the CLP Source parameter is set to CB and the circuit breaker is open, the protection is blocked
off.
The CLP Source parameter, common for profi les A and B, is available inside the Set \ Starting
control set menu.
Note 1 The inverse time threshold, unlike the defi nite time, is not in any way conditioned by the CLP activation time
Setting example: I
MOT-ST
= 5I
LR>inv
With input current I = I
MOT-ST
and setting t
LR>inv
=10 s the operate time is t = 10 s
Operating characteristic concerning the locked rotor element (50S/51LR(48)/14)
F_48-Char.ai
t = t
LR
>
inv
· (I
MOT-ST
/I)
2
I
MOT-ST
I/
I
LR>inv
t [s]
1 2 3 4 5 6 7 8 9 10 20 50
0.01
0.1
1
10
100
250
1000
10 000
t
LR>inv
= 1 s
t
LR>inv
= 10 s
t
LR>inv
= 200 s
t
LR>inv
= 100 s
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