1. DESCRIPTION
NX232A Earth-fault Relay User's Guide
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CASE DIMENSIONS
7. CONNECTION DIAGRAMS
a) Earth Fault Relay
Indicators
Mechanical
Outputs
Figure 7: Case Dimensions
Setting Ranges
Low-set setting I>.....................0.10 - 5.00 A (2%-100%)
Time multiplier kt> ...................0.01 - 1.00
High-set setting I>> .................0.10 - 50.0 A (2%-1000%)
High-set definite time t>>.........0.00 - 100 s
Low-set definite time t > ..........0.00 - 100 s
6. TECHNICAL DATA
Ratings
Rated current
I
n
......................5 A
Frequency ...............................50 Hz or 60 Hz
Burden ....................................< 0.3 VA at
I
n
Auxiliary Supply
NX232A-240A ........................198~265 VAC
Supply frequency ....................50 Hz or 60 Hz
VA rating .................................3 VA typical
NX232A-110A..........................94~127 VAC
NX232A
R1
R2
NX233A
R1
R2
96 mm
96 mm
Front
110mm
100mm
90mm
90mm
L1
L2
L3
N
NX232A
R1
R2
Auxiliary supply .....................Green LED indicator
Pick up ..................................Red LED indicator
Trip ........................................7 segment LED and
Red LED indicators
NX232A-240AD ......................85~265 VAC/110~370 VDC
The NX232A is a microprocessor based
numerical earth-fault relay. It uses
fundamental frequency current
measurement for excellent harmonic
current rejection. The relay consists of
independent low-set and high-set
elements. The high-set element can be
disabled by the user. The time current
characteristics of the low-set elements
are definite time or five selectable IDMT
curves. The high-set element is a
definite time or instantaneous relay. The
4-digit panel display on the NX232A
allows the display of the present load
current; recorded fault current for last
tripping; and all settings of the relay.
2. LIGHT INDICATORS
The indicators display the status of the system as follow:
Table 1: System Status
1 = ON 0 = OFF X= don’t care, not blinking
B = blinking DT = DATA FUNC = FUNCTION
Indicator
Aux l> l>> FUNC DT Status
0 0 0 0 0 No Auxiliary power supply.
1 0 0 X X Normal condition, no tripping.
1 1 0 X X Low-set overcurrent triggered,
time delay countdown started.
1 0 1 X X High-set overcurrent triggered,
time delay countdown started.
1 B 0 B B Low-set tripped,
DT LEDs show tripped value.
1 0 B B B High-set tripped,
DT LEDs show tripped value.
1 X X 1 B Programming mode.
b) Overcurrent Relay and Earth fault relay (3 phase 4 wire system)
Thermal withstand.....................4 x In continuous
Rated voltage ..........................250 VAC
Continuous carry .....................5A (cos
= 1.0)
Expected electrical life ............10
5
operations
Expected mechanical life ........5 x10
6
operations
Environmental conditions
Temperature .......................... -10ºC to 55ºC
Humidity ................................ 5% to 95% non-condensing
Mounting................................ Panel mounting
Dimension (mm) .................... 96(w) x 96(h) x 110(d)
Enclosure protection.............. IP54 at the panel
Approximate weight............... 0.7 kg
Accuracy
Protection thresholds ...............± 5%
Time delay.................................± 5% with a
mimimum of 50ms
Rev M0 (04/19)
(0.00 - 1.00, step 0.01; 1.00-10.0, step 0.10;
10.0-100, step 0.5)
