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A-9
Unmatched discrimination
Discrimination
Compact NSX provides maximum continuity of service and savings through an
unmatched level of discrimination:
given the high accuracy of measurements, overload discrimination is ensured
b
even between very close ratings
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b
upstream device can anticipate the reaction of the downstream device. The
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for very high faults, the energy of the arc dissipated by the short-circuit in the
b
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discrimination is maintained whatever the short-circuit current.
For total discrimination over the entire range of possible faults, from the long-time
pick-up Ir to the ultimate short-circuit current Icu, a ratio of 2.5 must be maintained
between the ratings of the upstream and downstream devices.
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Understanding the names of Micrologic electronic trip units
Protection
Frame
Measurements
Applications
1
: I
2
: NSX100/160/250
A
: Ammeter
Distribution, otherwise
2
: LS
0
I
G
: Generator
5
: LSI
M
: Motors
6
: LSIG
I
: Instantaneous
3
: NSX400/630
E
: Energy
L
: Long time
S
0
: Short time
(1)
¿[HG GHOD\
S
: Short time
G
: Ground fault
Examples
Micrologic 1.3
Instantaneous only
400 or 630 A
Distribution
Micrologic 2.3
LS
0
I
400 or 630 A
Distribution
Micrologic 5.2 A
LSI
100, 160 or 250 A
Ammeter
Distribution
Micrologic 6.3 E-M
LSIG
400 or 630 A
Energy
Motor
(1)
LS
0
I protection is standard on Micrologic 2. To ensure discrimination, it offers short-time protection S
0
with a non-adjustable
delay and instantaneous protection.
DB112094
DB112155
DB112120
DB112156
DB111354
N
S
400
N
SX2
50
N
S
1
6
0
(100
A
)
N
SX
100
Multi 9
Compact NSX100 with Micrologic for total discrimination.*
Better coordination between protection functions reduces the
difference in ratings required for total discrimination.
* Please refer to supplementary technical catalogue.
559E1100.indd
version: 1.0