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DIR 1000587R0002 (Version 02)
3.
LSIG-MM Trip Unit
3.1. Introduction
LSIG-MM possesses many common characteristics:
- Graphic interface: display, push-buttons and interactive menu.
- HW: connectors and accessory modules.
- SW: basic protection and measuring functions.
3.2. Overview
External accessories
External Neutral Sensor
Temporary accessories (test connector)
Battery Unit
MM
Values
available
G
I
S
L
3.3. Specifi cations
LSIG-MM, for 140G-N/140G-NS/140G-R circuit-breakers, is electronic device with functions for monitoring and for protecting
against fault currents.
The units also possess Measuring, Data Storage, Self-diagnosis, Load Control functionality.
The trip unit installed in the circuit-breaker is connected to the current sensors for primary current reading, to the Trip Coil for the
circuit-breaker opening command and to the CB state contacts.
The sensors provide the primary current measurement and energy for powering the trip unit even in the absence of external
power supply.
Connected directly to an opening mechanism, the Trip Coil allows the CB to open. The command is transmitted to the Trip coil
in accordance with the protection settings.
The state contacts of the CB provide information about the CB's position.
A graphic display and a set of push-buttons allow all the information about the trip unit to be accessed. They can also be used
for adjusting the protections and settings and for reading the state and alarms. In addition, the presence of alarms is indicated
by two front leds.
3.3.1.
Protections
The adjustable protections available are:
Symbol
Protection against
L
overload with inverse long time delay
S
overload with adjustable delay
I
instantaneous short-circuit
G
earth fault with adjustable delay
U
phase unbalance
OT
temperature off range
MM
Instantaneous short-circuit (maintenance mode)
In addition, LSIG-MM provides fi xed protection against instantaneous short-circuits at high currents, known as Iinst.
3.3.2. Functions
LSIG-MM includes various different functions:
- Runtime measurement of the main electrical quantities available: phase current, peak factor;
- Programmable measurements: periodic storage of maximum and minimum signals and waveforms;
- Autotest: continuous monitoring of the main connections to the trip unit, among which: current sensors, trip coil, rating plug,
circuit-breaker state.
- Maintenance information and counters: number of operations, estimated contact wear, events log.
