MicroLogic 2 AB and 4 AB Electronic Trip Units
Introduction
The MicroLogic 2 AB and 4 AB electronic trip units are used in public distribution to limit the intensity provided to the subscriber according to the contract signed up for.
The MicroLogic 2 AB and 4 AB electronic trip units exist in 4-pole configuration only. They have the same characteristics as MicroLogic 2 and 4 respectively, with specific ratings and long-time protection settings.
Description
The adjustment dials and indications are on the front face.
-
A MicroLogic electronic trip unit setting range
B Selection dial for setting the neutral protection
C Ready LED (green)
D Overload pre-alarm LED (orange): 90% lr
E Overload alarm LED (red): 105% lr
F Test port
G Adjustment dial for the long-time protection pickup lr
H Adjustment dial for the short-time protection pickup Isd
I Value of instantaneous protection pickup Ii
J Adjustment dial for the earth-leakage protection pickup IΔn
K Earth-leakage fault indicator: yellow when earth-leakage fault is detected
L Test button (T) for periodic earth-leakage function test
M Adjustment dial for earth-leakage time delay Δt
N Switch to disconnect trip unit supply from the phases, used when performing a panel dielectric test
The trip unit rating In corresponds to the maximum value of the adjustment range.
Setting the Long-Time Protection
The long-time protection pickup Ir is set by using a multi-position dial. The maximum setting value (maximum setting on adjustment dial) equals the trip unit rating value In.
The following table shows for every trip unit rating the values of the pickup Ir (in amperes) for long-time protection that are displayed directly on the dial.
|
Trip unit rating In (A) |
Pickup Ir (A) |
|||||||
|---|---|---|---|---|---|---|---|---|
|
100 |
40 |
40 |
50 |
60 |
70 |
80 |
90 |
100 |
|
160 |
90 |
100 |
110 |
120 |
130 |
140 |
150 |
160 |
|
240 |
140 |
150 |
160 |
170 |
180 |
200 |
220 |
240 |
|
400 |
260 |
280 |
300 |
320 |
340 |
360 |
380 |
400 |
The long-time protection time delay cannot be adjusted. The following table shows the value of the trip time delay according on the current in the load:
|
Current in the load In |
Trip time delay |
|---|---|
|
1.5 x Ir |
15 s |
|
6 x Ir |
0.5 s |
|
7.2 x Ir |
0.35 s |
Other Protection Settings
For all other protection settings on MicroLogic 2 AB trip units, refer to MicroLogic 2 Electronic Trip Units.
For all other protection settings on MicroLogic 4 AB trip units, refer to MicroLogic 4 Electronic Trip Units.