Siemens 3RT2028-2BB44-3MA0 SIRIUS 3RT2 Power Contactor 38A, 18.5kW, 24V DC Coil, Size S0, Spring-Loaded Terminal Original Brand New

Overview

The Siemens SIRIUS 3RT2028-2BB44-3MA0 is a high-performance 3-pole power contactor designed for switching motors and other resistive loads. As part of the SIRIUS 3RT2 series, it is engineered for exceptional reliability, compactness, and longevity in industrial control applications. Featuring a robust $24\text{ V DC}$ control voltage, it offers secure and efficient operation, particularly in scenarios requiring permanent auxiliary switching and spring-loaded connection technology for vibration-proof and fast wiring. It is rated for $38\text{ A}$ (AC-3e/AC-3) and $18.5\text{ kW}$ at $400\text{ V}$.

Key Features and Specifications

• Product Number: 3RT2028-2BB44-3MA0
• Contactor Series: Siemens SIRIUS 3RT2
• Application Rating: AC-3e/AC-3 (Motor Switching)
• Rated Operating Current (Ie​): $38\text{ A}$ at $400\text{ V}$
• Rated Operating Power: $18.5\text{ kW}$ at $400\text{ V}$
• Poles: 3-pole main circuit
• Control Supply Voltage: $24\text{ V DC}$ (for coil actuation)
• Auxiliary Contacts: Built-in $2\text{ NO}+2\text{ NC}$ (Normally Open + Normally Closed)
• Terminal Type: Spring-loaded terminals (for secure, time-saving wiring)
• Contactor Size: S0
• Special Feature: Captive/Permanently Mounted Auxiliary Switch (for enhanced safety/SUVA applications)
• Surge Suppression: No surge suppressor retrofittable (requires external protection if needed)
• Max Operating Voltage (Main Circuit): $690\text{ V}$

Benefit

• Reliable Motor Switching: Rated for demanding AC-3e/AC-3 applications, ensuring stable control for motors up to $18.5\text{ kW}$.
• Quick & Secure Wiring: Spring-loaded terminals provide a gas-tight, vibration-proof connection, drastically reducing wiring time and increasing operational reliability compared to screw terminals.
• Space-Saving Design: Size S0 form factor offers a compact footprint, optimizing panel space in control cabinets.
• Enhanced Diagnostics: Integrated $2\text{ NO}+2\text{ NC}$ auxiliary contacts allow for comprehensive status monitoring and control circuit integration without needing external add-on blocks.
• Long Mechanical Service Life: Typical mechanical operating cycles of $10,000,000$ ensure long-term, maintenance-free operation.
• Global Standard Compliance: Manufactured in Germany, conforming to international standards (IEC, EN 60947-1).

Function / Application

The Siemens 3RT2028-2BB44-3MA0 power contactor is primarily used in industrial automation and control systems for switching 3-phase AC motors and resistive loads. Its robust design and high current/power ratings make it ideal for:

• Controlling pumps, fans, and compressors.
• Switching heating systems and lighting circuits.
• Building reliable load feeders in control panels.
• Integration into complex control systems where a $24\text{ V DC}$ control signal is standard (e.g., PLCs).

The permanent auxiliary switch makes it particularly suited for applications requiring mandatory safety interlocking and positive-guided contacts (often specified for safety-related control circuits like in SUVA applications).

For more of our high-quality industrial automation products, including the full Siemens SIRIUS range and other essential control gear, visit turll today!