ABB PR331/P LSIG S/N:9MT9DMD19370Q042

Overview

ABB PR331/P LSIG is a microprocessor-based electronic trip unit for ABB SACE Tmax T7 / T8 and Emax X1 series molded case circuit breakers, the serial trace code 9MT9DMD19370Q042 is used for production and component traceability. LSIG stands for Long-time overload, Short-time delay, Instantaneous short-circuit and Ground-fault protection, covering full protection functions for low-voltage distribution feeders. It is widely supplied as exchange spare for industrial main switchboard, factory power distribution, building and data center feeder cabinet overhaul and breaker retrofit.

Features

ABB PR331/P LSIG provides adjustable inverse long-time thermal protection for cables and load equipment, short-time delay function to realize selective coordination between upstream and downstream protective devices, instantaneous protection for severe short-circuit faults, and residual ground fault protection for earth leakage risk prevention. It is self-powered by the built-in CTs of the MCCB, so core protection functions remain active even when auxiliary control power fails. ABB PR331/P LSIG supports local adjustment of pickup current and time delay parameters via front dials, and can be equipped with optional communication modules to transmit current, fault status and alarm signals to PLC, SCADA and BMS systems. It records fault trip history and can cooperate with ABB Ekip service software for parameter reading and maintenance diagnosis. It conforms to IEC 60947-2 standard and EMC requirements for low-voltage switchgear.

Specs

ABB PR331/P LSIGPlatform: ABB SACE Tmax T7, T8 / Emax X1 MCCB Type: microprocessor electronic trip release Serial number: 9MT9DMD19370Q042 Protection functions: L (long-time), S (short-time), I (instantaneous), G (ground fault) Power source: self-powered via breaker internal current transformers Mounting: installed inside corresponding T7 / T8 / X1 frame molded case circuit breaker Enclosure rating: IP40 front This is not a complete circuit breaker or I/O module; it is the dedicated electronic protection trip unit. ABB PR331/P LSIG is widely supplied as service replacement spare for protection release failure and protection upgrade.

Principle

ABB PR331/P LSIG continuously samples three-phase current signals from the breaker CTs. The internal microcontroller compares measured values against preset thresholds. Overload adopts inverse time curve for delayed tripping to avoid nuisance trips during motor starting; short-time delay setting ensures selectivity; instantaneous protection trips immediately for high-magnitude short circuit; ground fault function detects residual current caused by insulation damage. When any fault condition is triggered, the trip unit outputs a drive signal to the breaker operating mechanism and sends alarm information to the remote monitoring system. Fault records are stored inside the unit for maintenance root cause analysis.

Applications

ABB PR331/P LSIG is deployed for incoming feeders, bus tie circuits, large motor feeders and distribution branch protection in industrial plants, commercial buildings and data center low-voltage switchrooms. It is selected for spare inventory and panel retrofit projects for existing ABB Tmax T7 T8 and Emax X1 distribution systems.