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Functions and
characteristics
Accessories for
Micrologic trip units
External neutral current transformer (ENCT)
The external transformer is a sensor required for a three-pole circuit breaker in a
system with a distributed neutral to measure the neutral current in order to:
protect the neutral conductor
b
protect against insulation faults.
b
This current transformer can be connected to Micrologic 5 / 6 trip units. The
transformer rating must be compatible with that of the circuit breaker.
Required current transformers for different circuit breaker models
Type of circuit breaker
Rating
Catalogue
number
NSX100/160/250
25 – 100 A
LV429521
150 – 250 A
LV430563
NSX400/630
400 – 630 A
LV432575
External neutral voltage tap (ENVT)
The neutral voltage transformer is required for Micrologic E power metering with a
three-pole circuit breaker in a system with a distributed neutral. It is used to connect
the neutral to the Micrologic trip unit to measure phase-to-neutral (Ph-N) voltages.
External 24 V DC power-supply module
Use
An external 24 V DC power supply is required for installations with communication,
whatever the type of trip unit.
On installations without communication, it is available as an option for Micrologic 5/6
in order to make it possible to:
modify settings when the circuit breaker is open
b
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b
(15 to 50 A depending on the rating)
maintain the display of the cause of tripping and interrupted current.
b
Characteristics
A single external 24 V DC supply may be used for the entire switchboard.
The required characteristics are:
output voltage: 24 V DC ±5 %
b
ripple: ±1%.
b
overvoltage category: OVC IV - as per IEC 60947-1
b
External 24 V DC power-supply modules with an output current of 1 A are available:
Available external power-supply modules
Cat. no.
Power supply
V DC (±5 %)
24/30
54440
48/60
54441
100/125
54442
V AC (+10 %, -15 %)
110/130
54443
200/240
54444
380/415
54445
Output voltage
24 V DC (±5 %)
Ripple
±1 %
Overvoltage category (OVC)
OVC IV - as per IEC 60947-1
An external 24 V DC power-supply module with an output current of 3 A is also
available:
Available external power-supply modules
Cat. no.
Power supply
V DC
110/230
ABL8RPS24030
V AC
110/240
Output voltage
24 V DC (±5 %)
Ripple
±1 %
Overvoltage category (OVC)
OVC II
Total consumption
To determine the required output current of the 24 V DC power supply, it is necessary
to sum up the currents consumed by the different loads supplied:
Consumption of Compact NSX modules
Module
Consumption (mA)
Micrologic 5/6
20
BSCM module
10
FDM121
40
Modbus communication interface
60
NSX cord U > 480 V AC
30
PB103843-18
External neutral current transformers.
PB103583-18
External 24 V DC power-supply module.
PB103842-47
External neutral voltage tap (cat. no. LV434208).
559E1400.indd
version: 1.0
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