Characteristics of Micrologic Electronic Trip Units
Micrologic electronic trip units provide the following functions:
oProtection of the electrical distribution or specific applications
oMeasurement of instantaneous values and measurement of average values (demand) for electrical quantities
oKilowatt hour metering
oOperational assistance such as peak demand, customized alarms, and operation counters
oCommunication
Identify the trip unit installed on the circuit breaker by using the fourcharacters on the front face:
| Protection (X) | Case (Y) | Measurements (Z) | Application (T) | |||||
|---|---|---|---|---|---|---|---|---|
|
|
|
|
| |||||
| 1 2 4 5 6 7 | SI LS0I LS0IR LSI LSIG LSIR | 2 3 | CompactNSX 100/160/250 CompactNSX 400/630 | – A E | No measurement Ammeter Energy | – G AB M Z AL | Distribution Generator Subscriber Motor 16Hz2/3 Alarm | |
| Examples | ||||||||
| Micrologic1.3 | SI | 400 or 630A | – | Distribution | ||||
| Micrologic2.2G | LS0I | 100, 160 or 250A | – | Generator | ||||
| Micrologic2.3 | LS0I | 400 or 630A | – | Distribution | ||||
| Micrologic 2.3M | LS0I | 400 or 630A | – | Motor | ||||
| Micrologic4.2 | LS0IR | 100, 160 or 250A | – | Distribution including trip on earth leakage | ||||
| Micrologic4.3AL | LS0I | 400 or 570A | – | Distribution including alarm on earth leakage | ||||
| Micrologic 5.2A | LSI | 100, 160 or 250A | Ammeter | Distribution | ||||
| Micrologic 5.3E | LSI | 400 or 630A | Energy | Distribution | ||||
| Micrologic 6.3E-M | LSIG | 400 or 630A | Energy | Motor | ||||
| Micrologic 7.2E-AL | LSI | 100, 160 or 250A | Energy | Distribution including alarm on earth leakage | ||||
| Micrologic 7.3E | LSIR | 400 or 630A | Energy | Distribution including trip on earth leakage | ||||
| Type of protection: IInstantaneous LLong-time S0Short-time (time delay cannot be adjusted) SShort-time GGround-fault R Residual (earth-leakage) | ||||||||
The range of Micrologic trip units is made up of several families:
oMicrologic1, 2, and 4 without display screen
oMicrologic5, 6, and 7 with display screen.
On Micrologic1, 2, and 4 trip units, the protection functions are set using adjustment dials on the front face of the trip unit:
On Micrologic5, 6, and 7 trip units, the protection functions are set:
oBy using the adjustment dials
oBy additional settings on the keypad. Setting values are displayed on the screen
oThrough EcoStruxure Power Commission software.
For more information about the Micrologic5, 6, and 7 trip units, refer to DOCA0141EN, CompactNSX Micrologic5/6/7 Electronic Trip Units - User Guide.
In Rating of Micrologic Trip Units
The In rating (in amps) of a Micrologic trip unit corresponds to the maximum value of the long-time protection (Ir) setting range for the trip unit. The setting range is indicated on the label on the front face of the trip unit (this label is visible on the front face of the CompactNSX circuit breaker after the trip unit has been fitted).
Example: Micrologic 5.2A 250 trip unit:
oSetting range: 100-250A
oIn rating = 250A
The following figure and table define the protection functions for distribution-type Micrologic trip units.
| Micrologic5 and 6
| Micrologic7
|
| Item | Parameter | Description | Micrologic(1) | |||||
|---|---|---|---|---|---|---|---|---|
| 2 | 4 | 5 | 6 | 7 | ||||
| A | – | Trip unit setting range: minimum setting/maximum setting. The trip unit rating In corresponds to the maximum value of the Ir setting range. | O | O | O | O | O | |
| B | Ir | Long-time protection pickup | L | ✓ | ✓ | ✓ | ✓ | ✓ |
| C | tr | Long-time protection time delay | O | O | ✓ | ✓ | ✓ | |
| D | Isd | Short-time protection pickup | S | ✓ | ✓ | ✓ | ✓ | ✓ |
| E | tsd | Short-time protection time delay | O | O | ✓ | ✓ | ✓ | |
| F | I2t ON/OFF | Short-time protection I2t curve in ON or OFF position | – | – | ✓ | ✓ | ✓ | |
| G | Ii | Instantaneous protection pickup | I | O | O | ✓ | ✓ | ✓ |
| H | Ig | Ground-fault protection pickup | G | – | – | – | ✓ | – |
| I | tg | Ground-fault protection time delay | – | – | – | ✓ | – | |
| J | I2t ON/OFF | Ground-fault protection I2t curve in ON or OFF position | – | – | – | ✓ | – | |
| K | IΔn | Earth-leakage protection pickup | R | – | ✓ | – | – | ✓ |
| L | Δt | Earth-leakage protection time delay | – | ✓ | – | – | ✓ | |
| (1)Functions: ✓: Adjustable O: Fixed –: Not present | ||||||||
The thermal memory is used to simulate temperature build-up and cooling in conductors caused by current variations, according to a time constant. In the event of an overload, the trip units with a thermal memory memorize the build-up temperature caused by the current. Memorizing the build-up temperature leads to a reduction in the trip time.
All Micrologic trip units incorporate a thermal memory as standard:
oFor Micrologic2 and 4 trip units, the time constant is 15minutes.
oFor Micrologic5, 6, and 7 trip units, the time constant is 20minutes.
The following figure and table define the protection functions for Micrologic typeM trip units.
| Item | Parameter | Description | Micrologic typeM | |||
|---|---|---|---|---|---|---|
| 1.3 | 2 | 6E | ||||
| A | – | Trip unit setting range: minimum setting/maximum setting. The trip unit rating In corresponds to the maximum value of the setting range. | O | O | O | |
| B | Ir | Long-time protection pickup | L | – | ✓ | ✓ |
| C | Class | Long-time protection trip class | – | ✓ | ✓ | |
| D | Isd | Short-time protection pickup | S | ✓ | ✓ | ✓ |
| E | tsd | Short-time protection time delay | O | O | O | |
| F | Ii | Instantaneous protection pickup | I | O | O | O |
| G | Ig | Ground-fault protection pickup | G | – | – | ✓ |
| H | tg | Ground-fault protection time delay | – | – | ✓ | |
| – | Iunbal | Phase-unbalance protection pickup |
| – | O | ✓ |
| – | tunbal | Phase-unbalance protection time delay | – | O | ✓ | |
| (1) Functions: ✓: Adjustable O: Fixed – : Not present | ||||||
Motor Trip Unit: Additional Protection
Micrologic typeM trip units (in particular Micrologic6E-M) also incorporate additional protection for the motor application. For more information, refer to DOCA0141EN, CompactNSX Micrologic5/6/7 Electronic Trip Units - User Guide.
Indication LEDs on the front of the trip unit indicate its operational state.
The LEDs and their meaning depend on the type of Micrologic trip unit.
| Type of Micrologic trip unit | Description |
|---|---|
| Distribution
| oReady LED (green): Blinks slowly when the electronic trip unit is ready to provide protection. oOverload pre-alarm LED (orange): Shows a steady light when the load exceeds 90% of the Ir setting. oOverload alarm LED (red): Shows a steady light when the load exceeds 105% of the Ir setting. |
| Motor
| oReady LED (green): Blinks slowly when the electronic trip unit is ready to provide protection. oOverload temperature alarm LED (red): Shows a steady light when the motor thermal image exceeds 95% of the Ir setting. The Micrologic1.3M trip unit, which provides short-time protection only, displays the Ready LED (green). |
The indication LEDs function for circuit breaker load currents:
oAbove 15A on a Micrologic trip unit rated 40A
oAbove 30A on Micrologic trip units rated >40A
The limit value is indicated on the front panel, above the Ready LED of the Micrologic trip unit.
NOTE: For the Micrologic 4 and 7 trip units, the protection functions are supplied by a second power supply, in addition to the current transformer supply. The Ready LED blinks irrespective of the load, indicating that the standard protection functions are operational.
To activate the Ready LED when the load current is below the limit value, you can:
oInstall a 24Vdc external power supply module which allows the trip unit to be monitored continuously, even when the circuit breaker is open. For more information, refer to Compact NSX&NSXm Catalogue.
oOr, during maintenance visits, connect the pocket battery to monitor the trip unit.
NOTE: If the pre-alarm and alarm LEDs keep lighting up, perform load shedding to avoid tripping due to a circuit breaker overload.
Micrologic trip units come with a test port specifically for testing trip unit operation.
This port is designed for:
oConnecting the pocket battery for local Micrologic testing
oConnecting the USB maintenance interface for testing, setting the Micrologic trip unit, or for installation diagnostics
Interchangeability of Micrologic Trip Units
Onsite replacement of trip units is simple:
oNo connections to make
oNo special tools (for example, calibrated torque wrench)
oCompatibility of trip units provided by mechanical cap
oTorque limited screw provides correct torque
The simplicity of the replacement process means that it is easy to make the necessary adjustments as operation and maintenance processes evolve.
NOTE: The screw head is accessible when the trip unit is installed, so the trip unit can still be removed.
NOTE: On the CompactNSX with R, HB1 and HB2 breaking performances the trip units are not interchangeable.
Seal the transparent cover on Micrologic trip units to prevent modification of the protection.
On Micrologic5, 6, and 7 trip units, it is possible to use the keypad, with the cover sealed, to read the protection settings and measurements.
