MicroLogic 2 G Electronic Trip Unit
Introduction
The MicroLogic 2 G electronic trip unit is used to protect distribution systems powered by generators or distribution systems with long cables.
Description
The adjustment dials and indications are on the front face.
A MicroLogic 2G electronic trip unit setting range
B Ready LED (green)
C Overload pre-alarm LED (orange): 90% Ir
D Overload alarm LED (red): 105% Ir
E Test port
F Preset dial for the long-time protection pickup Io
G Fine-tuning dial for the long-time protection pickup Ir
H Adjustment dial for the short-time protection pickup Isd
I Value of instantaneous protection pickup Ii
The trip unit rating In corresponds to the maximum value of the setting range.
Setting the Long-Time Protection
The long-time protection pickup Ir is set using two multi-position dials.
-
The preset dial allows the pickup to be preset to the value Io (displayed in amperes on the dial).
The maximum preset value (maximum setting on preset dial) equals the trip unit rating value In.
-
The adjustment dial can be used to fine-tune the pickup Ir (value displayed in multiples of Io on the dial).
|
Step |
Action |
|---|---|
|
1 |
Set both adjustment dials to maximum (for Io: to the value In (A); for Ir: to 1). |
|
2 |
Turn the Io preset dial higher than the value required. The Ir setting value is: Io setting (A). |
|
3 |
Turn the fine-tuning dial to adjust the value of Ir from 0.9 x Io to Io. |
|
4 |
The Ir setting value is: Io (A) setting x fine tuning. |
The time delay tr for long-time protection cannot be adjusted.
The following table shows the value of the time delay tr for long-time protection (in seconds) according to the overload current (in multiples of Ir):
|
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 |
The precision range is - 20%, + 0%.
Setting the Short-Time Protection
The short-time protection pickup Isd is set by a multi-position dial.
The setting value is expressed in multiples of Ir.
|
Step |
Action |
|---|---|
|
1 |
Set the long-time protection first: the setting pickup is Ir (A). |
|
2 |
Turn the Isd adjustment dial to the value required. The Isd value is adjustable from 1.5 x Ir to 9 x Ir. |
|
3 |
Isd is set to Ir (A) x Isd setting. |
The precision range is +/- 10%.
The time delay tr for short-time protection cannot be adjusted:
-
Non-trip time: 140 ms
-
Maximum breaking time: 200 ms.
Setting the Instantaneous Protection
The pickup Ii for instantaneous protection cannot be adjusted.
The following table shows the value of the pickup Ii for instantaneous protection (in amperes) according to the trip unit rating In:
|
Trip unit rating In (A) |
40 |
100 |
160 |
250 |
|---|---|---|---|---|
|
Pickup Ii (A) |
600 |
1500 |
2400 |
3000 |
The precision range is +/- 15%.
The time delay for instantaneous protection cannot be adjusted:
-
Non-trip time: 15 ms
-
Maximum breaking time: 50 ms.