SCHNEIDER ELECTRIC 33073BA Micrologic 6.0A LSIG Electronic Trip Unit

Overview

The SCHNEIDER ELECTRIC 33073BA is a Micrologic 6.0A electronic protection trip unit for Schneider Masterpact NT / NW series air circuit breakers. The SCHNEIDER ELECTRIC 33073BA provides full LSIG protection functions including long time overload, short time short circuit, instantaneous short circuit and ground fault protection. It supports adjustable protection curves, fault recording and local status indication, and can connect with communication modules for remote monitoring by DCS and SCADA systems. The SCHNEIDER ELECTRIC 33073BA is widely stocked as spare trip unit for low voltage main distribution breaker maintenance and replacement.

Features

The SCHNEIDER ELECTRIC 33073BA supports independent setting of L, S, I and G protection thresholds and time delays to achieve selective protection in multi-layer power distribution systems. It stores trip history, fault current value and operating data for fast on-site troubleshooting. The SCHNEIDER ELECTRIC 33073BA has built-in self-diagnosis function for internal circuit and current transformer abnormality. It supports external communication accessory plug-in for Modbus and network data upload. The SCHNEIDER ELECTRIC 33073BA adopts front plug-in structure and matches the breaker interface and wiring definition for direct replacement.

Specs

Device Type: Micrologic electronic trip unit Model: SCHNEIDER ELECTRIC 33073BA Version: Micrologic 6.0A Protection: L long time overload, S short time delay, I instantaneous, G ground fault Applicable Breaker: Masterpact NT, Masterpact NW air circuit breaker Power Supply: Powered by built-in current transformer Diagnosis: Fault memory, self-test, LED status indicator Communication: Expandable via communication module Mounting: Front plug-in on circuit breaker Application: Low voltage main incoming cabinet, bus tie protection, heavy load distribution feeder

Principle

The SCHNEIDER ELECTRIC 33073BA samples three-phase and neutral current signals from the current transformers inside the breaker. The internal processor calculates RMS current values and compares them with preset protection thresholds. When overload, short circuit or ground fault condition is detected, the SCHNEIDER ELECTRIC 33073BA outputs trip signal to the breaker release mechanism following the selected time delay curve. It records fault data and triggers alarm when internal hardware failure is detected.

Applications

The SCHNEIDER ELECTRIC 33073BA is used for main incoming and bus tie breaker protection in industrial power distribution rooms and commercial buildings. It serves selective protection for large motor feeders and critical process load loops. The SCHNEIDER ELECTRIC 33073BA applies to spare stock and emergency repair of existing Masterpact breaker assemblies. It also supports power distribution system renovation and protection coordination adjustment projects.