K31E ABB K-Series Standard Control Relay 4-Pole

Product Overview

The K31E (K 31E) by ABB is a high-performance, industrial-grade standard control relay engineered for precision switching in AC control circuits. As a cornerstone of the legendary ABB K-Series, this 4-pole device features a specialized 3NO + 1NC (3 Normally Open + 1 Normally Closed) contact configuration, making it indispensable for complex automation logic and motor control interlocking. Designed to withstand the rigorous demands of power plants, heavy manufacturing, and water treatment facilities, the K31E excels in high-duty cycle environments. By integrating this relay into your control architecture, you ensure reliable signal isolation and auxiliary switching, significantly reducing unplanned downtime and enhancing system-wide operational safety.

Technical Specifications

FAQs

How does the integrated RC-unit benefit the K31E relay lifespan?

The external Murrelektronik RC-B 30/220 suppressor protects the relay coil by clamping inductive voltage peaks during de-energization. This prevents insulation breakdown and minimizes electromagnetic interference (EMI) in nearby sensitive PLC I/O modules.

Can the K31E be used for DC load switching?

While the K31E is optimized for AC-11 utilization categories (auxiliary electromagnetic loads), switching DC loads requires significant derating due to the lack of a natural zero-crossing for arc extinction. Contact our technical team for specific DC-13 ratings.

What are the terminal requirements for secure wiring?

The device utilizes screw-clamp terminals. For high-vibration environments, we recommend using insulated crimp ferrules and maintaining a tightening torque of 1.0 to 1.2 Nm to prevent contact resistance buildup.

Is the K31E compatible with modern ABB AF-Series accessories?

The K-Series is a legacy-standard architecture. While certain DIN-rail mounting components are universal, electrical accessories like auxiliary contact blocks should be verified for mechanical interlocking compatibility with the K-line frame.

Engineering & Installation Guide

• Surge Suppression Alignment: Ensure the RC-unit is mounted as close to the coil terminals (A1-A2) as possible. In 220 V control loops, the RC-B 30/220 unit is critical for preventing "back-EMF" which can cause ghost-tripping in solid-state logic controllers.

• Thermal Management in Enclosures: When mounting multiple K31E relays side-by-side, maintain a minimum lateral spacing of 5 mm if the ambient temperature exceeds 45 deg C. This prevents cumulative heat buildup from coil energization, ensuring the 10 A thermal current rating (Ith) remains valid.

• Safety Interlocking Logic: The 1 NC contact (21-22) should be utilized for "Fail-Safe" feedback or electrical interlocking. In motor reversing applications, use this contact to physically break the coil circuit of the opposing contactor to prevent phase-to-phase shorts.