8. CASE DIMENSIONS
Figure 2: Case Dimensions
96 mm
96
m
m
Front
110mm
100mm
90
m
m
90mm
1. DESCRIPTION
NX231A Earth-fault Relay User's Guide
start/
start/
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 digit shows tripped value.
1 0
B
B
B High-set tripped,
DT digit shows tripped value.
1
X
X
1
B Programming mode.
The NX321A is a microprocessor based
numerical earth-fault relay. It uses
fundamental
frequency
current
measurement for excellent harmonic
current rejection. The relay provides
two-element (low-set and high-set)
earth-fault protection with definite time
characteristic. The 4-digit LED indicator
on the NX231A allows the display of
present load current; recorded fault
current for last tripping; and all setting of
the relay
Rev M0 (04/19)
