Description

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1. Product Title

Siemens WLETU776 – WL Series Electronic Trip Unit (ETU776) for Low-Voltage Power Circuit Breakers

2. Product Overview

The WLETU776 is an electronic trip unit designed for advanced protection and control of low-voltage power circuit breakers in industrial power distribution systems. Developed by Siemens, this module belongs to the WL series of circuit breaker accessories and provides intelligent protection functions for high-current electrical networks.

The WLETU776 integrates electronic protection logic with a graphic LCD interface, enabling operators to configure protection parameters and monitor breaker status directly from the unit. It is commonly installed in WL series circuit breakers used in switchgear and power distribution panels. By implementing protection functions such as long-time, short-time, and instantaneous trip detection, the WLETU776 helps prevent equipment damage, electrical faults, and downtime in critical industrial power systems.

3. Technical Specifications

• Product Model: WLETU776

• Brand: Siemens

• Warranty: One Year

• Input Voltage: 24 V DC auxiliary power (for electronic functions)

• Operating Temperature: 0 °C to +60 °C

• Storage Temperature: –40 °C to +85 °C

• Response Time: Electronic trip response with configurable protection curves

• Protection Class: Designed for switchgear cabinet installation

• Accuracy Class: Industrial protection-grade measurement accuracy

• Output Frequency: Not applicable

• Rated Current Range: 200 A – 5000 A (depending on rating plug configuration)

• Communication Interface: Internal CubicleBUS / system accessories interface

• Supported Protocols: Compatible with WL breaker communication modules

• Overload Capacity: Designed to detect and trip during overload and short-circuit conditions

• Dimensions: Approx. 3 × 9 × 1 in (7.6 × 22.9 × 2.5 cm)

4. Main Features and Benefits

Electronic Protection Functions (LSI):
The module provides Long-time (L), Short-time (S), and Instantaneous (I) protection functions to detect overload and short-circuit faults quickly, ensuring reliable circuit protection.

Graphic LCD Interface:
A built-in graphical display allows operators to view trip events, system parameters, and configuration settings directly from the breaker interface.

Flexible System Integration:
The unit integrates with WL series breakers and accessories via Siemens’ internal communication bus, supporting monitoring, diagnostics, and optional protection features.

5. Application Scenarios

Industrial Power Distribution:
Installed in WL series low-voltage power circuit breakers used in manufacturing plants and heavy industry switchgear systems.

Power Generation Facilities:
Provides reliable protection for auxiliary distribution panels and generator support systems.

Commercial and Infrastructure Electrical Systems:
Used in large buildings, data centers, and infrastructure projects where high-current circuit protection is essential.

6. Frequently Asked Questions (FAQ)

Q: What are the main functions of WLETU776?
A: The module provides electronic protection functions including long-time, short-time, and instantaneous trip protection for WL series circuit breakers.

Q: Is WLETU776 compatible with legacy systems?
A: Yes. The trip unit is designed for Siemens WL low-voltage power circuit breakers and can often be installed as a replacement or upgrade within existing WL switchgear systems.