INSTALLATION
141
NA30 - Manual - 04 - 2022
Amperometric inputs
The amperometric input circuits are assembled inside the fixed module, so no short circuit on the
secondary CT must be provided when the removable module is pulled out.
When making the current connections, attention must be paid to not exceeding the performance of
the line current transformers. To be exact, the total load, constituted by the NA30 protective relay,
any other protective relays or measuring instruments and the resistance of the connections, must
not exceed the line CT performance. In particular, consumption of the NA30 relay input circuit must
not exceed 0.2 VA while the load (expressed in VA) constituted by the conductors is given by:
0.018 × L ×
I
n
2
/ S
where:
L the overall length, expressed in m, of the two conductors in relation to each phase;
I
n
nominal current of the line CT expressed in A;
S cross sectional area of the current conductors expressed in mm
2
.
It is recommended that cabling of a suitable thickness be used in order to limit wear of the CT sec-
ondary circuits
Binary inputs
The dry input circuits, despite being galvanically isolated, must preferably be supplied with the same
auxiliary voltage of the control panel.
The inputs are polarity free with wide voltage range.
The optoisolated inputs are immune to transitory interferences, however the following recommenda-
tion must be considered in high disturbed environments:
• Position input wiring away from high energy sources.
• Set a debounce timer (tON and/or tOFF) to alloy the transient to decay.
• Use shielded cables with ground connection on only one end (preferably at the relay side.
Output relays
Six output relays are available.
It is advisable to verify that the technical characteristic of the contacts be suitable for the applied
load (about current, nominal voltage, make and break current , etc..).
Output relay K1 and K2 have one change over contacts (SPDT, type C).
Output relay K3 and K4 have one make contact (SPST-NO, type A) and a common reference (A10
terminal).
Output relay K5 and K6 have one make contact (SPST-NO, type A for K5), one break contact (SPST-
NC, type B for K6) and a common reference (A13 terminal).
All contacts are shown in de-energized state for standard reference.
In case of disconnection CT wiring to the case, pay attention must to do not open live circuits.
CAUTION
Binary inputs
Binary-sch.ai
+
U
AUX
-
U
AUX
A19
A20
IN1
A
B
A21
A22
IN2
B1
B2
IN3
B3
B4
IN4
B5
B6
IN5
