LEDs and Display Screens

MicroLogic P trip units are equipped with overload and fault indication LEDs.

Overload LED

The overload LED indicates that the long-time current setting Ir has been overrun. The bar graph displays the overload as a percentage of Ir. The load level on each phase is displayed, with the most heavily loaded phase outlined.

Overload bar graph on the default screen
LED Indicator

Trip Cause Indications

A trip is signalled by the following means:

Trip cause indication LEDs
Trip cause notification displayed on the screen

The trip cause notifications depend on the following factors:

The presence of an external power supply. For more information about external power supplies, refer to Power supply.
The connection of voltage measurement inputs upstream or downstream.

Example showing trip unit without an external power supply and with voltage measurement input connected downstream	Example showing trip unit with an external power supply or with voltage measurement input connected upstream

Trip Cause Indication LEDs

The indications of the four trip cause LEDs depend on the type of MicroLogic trip unit.

LED	Description
	MicroLogic 5.0 P, 6.0 P, 7.0 P: Trip due to long-time protection
	MicroLogic 5.0 P, 6.0 P, 7.0 P: Trip due to short-time protection or instantaneous protection
	MicroLogic 5.0 P: Not applicable MicroLogic 6.0 P: Trip due to ground-fault protection MicroLogic 7.0 P: Trip due to earth-leakage protection
	MicroLogic 5.0 P, 6.0 P, 7.0 P: Trip due to auto-protection or additional protection Auto-protection functions: Temperature ASIC power supply Instantaneous pickup for circuit breaker self protection Additional protection functions: Current unbalance I unbal Maximum current I1 max, I2 max, I3 max, IN max Voltage unbalance U unbal Overvoltage U max Undervoltage U min Reverse power rP max Overfrequency F max Overfrequency F min

When activated, a LED remains ON until it is locally reset.

NOTE:

A number of simultaneous causes may result in tripping. The LED signalling the last trip cause chronologically is the only one to remain ON.
The battery maintains the trip cause indications. If there are no indications, check the battery.

Resetting Trip Cause Indications

Determine why the circuit breaker tripped. The trip cause indication is maintained until it is reset on the trip unit.
Press to reset the trip cause indication LED.

NOTE: If the circuit breaker remains closed and the Ap LED remains ON after the reset, open the circuit breaker and contact your field service representative.

For more information about the procedure for resetting and closing the circuit breaker after a trip, refer to DOCA0221EN ComPacT NS - Circuit Breakers and Switch-Disconnectors - User Guide.