Siemens 3RT2346-3XB40-4LA2 SIRIUS S3 Traction Contactor, 95A AC-3, 24V DC, Railway Approved Original Brand New

Overview

The Siemens 3RT2346-3XB40-4LA2 is part of the renowned SIRIUS modular system, specifically engineered to meet the stringent requirements of railway applications alongside standard industrial uses. This S3 frame size contactor excels in environments demanding high reliability, an extended temperature range, and superior resistance to mechanical oscillations and vibrations. Its compliance with railway-specific standards (IEC 60077-2, EN 50155) in addition to general industrial standards (IEC 60947-4-1) underscores its versatility and robust design.

Key Features & Benefit

• Exceptional Durability for Railway Applications: Built to withstand increased mechanical oscillations and vibrations, crucial for reliable operation in railway rolling stock.
• Extended Operating & Temperature Range: Functions reliably across a broad temperature spectrum from -40 to +70 °C, surpassing standard industrial contactors.
• Solid-State Operating Mechanism: Ensures precise and dependable control with a wide operating voltage range (0.7−1.25∗Uc​) for 24V DC coils, contributing to stable performance even with voltage fluctuations.
• Integrated Varistor: Provides effective coil damping and overvoltage protection for the control supply voltage, extending the lifespan of the device.
• Vibration-Resistant Connections: Features spring-loaded terminals for control and auxiliary circuits, significantly improving vibration resistance and reducing maintenance needs. Main circuit uses robust screw terminals.
• Compact & Modular Design: Part of the SIRIUS system (sizes S00 to S12), allowing for flexible integration and expansion with standardized accessories like auxiliary switches.
• High Performance: Capable of switching AC-3 motor loads up to 95 A (45 kW / 400 V), making it suitable for a wide range of industrial and traction motors.
• Enhanced Safety & Protection: Designed with considerations for short-circuit, overload, and overvoltage protection across all connections (main, auxiliary, control supply).

Function

• Motor Switching (AC-3): Efficiently switches 3-phase asynchronous motors, handling starting and stopping operations under normal running conditions.
• Power Switching: Capable of handling significant power loads up to 45 kW at 400V.
• Control and Signaling: Equipped with 1 normally open (NO) and 1 normally closed (NC) auxiliary contacts for feedback and control circuit integration.
• Coil Damping: Integrated varistor protects the operating mechanism against voltage transients, enhancing reliability.
• Wide Voltage Tolerance: The 24V DC solid-state operating mechanism tolerates voltage fluctuations from $0.7$ to $1.25$ times the rated control supply voltage (Uc​).

Standards & Approvals:

• IEC 60947-4-1: Low-voltage switchgear and controlgear – Part 4-1: Contactors and motor-starters – Electromechanical contactors and motor-starters.
• IEC 60077-2: Railway applications – Electric equipment for rolling stock – Part 2: Electrotechnical components – General rules.
• EN 50155: Railway applications – Rolling stock – Electronic equipment.

Application

The Siemens 3RT2346-3XB40-4LA2 is ideal for applications requiring exceptional reliability and robustness under challenging conditions. Its primary use includes:

• Railway Rolling Stock: Traction systems, auxiliary circuits, control systems in locomotives, trams, and other rail vehicles.
• Heavy Industrial Machinery: Equipment subjected to high vibrations, wide temperature swings, and requiring dependable motor control.
• Outdoor Installations: Applications where extreme temperature variations are common.

Installation & Protection Guidelines:

• Short-circuit & Overload Protection: All connections (main, auxiliary, control supply) must be protected using suitable measures. Refer to the technical product data sheet, Digital Configuration Manual for load feeders, and Configuration Manual for load feeders for detailed guidance.
• Overvoltage Protection: The integrated varistor provides internal coil damping. Further protection for the control supply voltage should consider relevant standards and the contactor’s load characteristics (inrush and holding power).
• Auxiliary Contact Expansion: The basic unit can be expanded with additional auxiliary switches, adhering to permissible configurations. Refer to the “Auxiliary switches, instantaneous” overview for more information.