Phoenix REL-IR Series Industrial Relays Selection Guide: AC/DC Voltage & Multi-Contact Configurations

Opening: Reliable Switching Solutions for Industrial Control Circuits

The Phoenix REL-IR series covers general-purpose (IR-BL/IR-BL/L) and enhanced (IR4) relay variants, supporting AC/DC power supplies (12V-230V) and 2/4 groups of changeover contacts (2X21/4X21). Key features include surge protection (LDP), explosion-proof (EX), dual-polarity (DP), and special contact (AU) designs, complying with industrial safety standards. Widely used in motor control, sensor-triggered circuits, safety interlocks, and hazardous environment applications, these relays ensure stable switching in harsh industrial conditions. This guide structures part number-model correspondence, core parameters, and scenario recommendations for efficient selection.

I. Core Advantages: Why Choose the REL-IR Series?

• Wide voltage compatibility: Supports 12DC/24DC/24AC/120AC/220DC/230AC, adapting to global industrial power systems (automation DC, mains AC).
• Flexible contact configurations: 2X21 (2 groups of changeover contacts: 1NO+1NC per group) and 4X21 (4 groups) to meet single/multi-circuit switching needs.
• Special function integration:
  • LDP: Built-in surge suppression for inductive loads (motors/solenoids), extending relay life;
  • EX: Explosion-proof design for hazardous environments (e.g., oil refineries, chemical plants);
  • AU: Special normally open contacts for high-reliability applications;
  • DP: Dual-polarity compatibility for AC/DC universal control;
  • L: Lockable design to prevent accidental operation.
• Industrial-grade reliability: Operating temperature -25°C to +60°C, anti-vibration (IEC 60068-2-6), suitable for factory floors and harsh environments.
• Easy installation: DIN rail mounting, compact design, and compatibility with Phoenix terminal blocks/control cabinets.

II. Complete Product Selection Table (Part Number + Model + Core Information)

1. Basic Series: REL-IR-BL/IR-BL/L (General-Purpose Relays)

Suitable for standard industrial switching scenarios, with 2/4 groups of contacts and lockable (L) options.

2. Enhanced Series: REL-IR4 (Surge Protection/Explosion-Proof/Dual-Polarity)

Optimized for harsh environments and special requirements (surge, explosion-proof, dual-polarity).

3. Special Series: REL-IRW/IRG (Simplified Function)

Simplified design for basic switching needs, no extra features.

III. REL-IR Series Nomenclature Decoding

REL-IR[Sub-series]-[Feature]-[Voltage]/[Contact Configuration]-[Special Suffix]

• Sub-series:
  • BL/L: Basic lockable; IR4: Enhanced (supports LDP/DP/EX); IRW/IRG: Simplified.
• Feature:
  • LDP: Surge protection (for inductive loads);
  • DP: Dual-polarity (AC/DC universal);
  • L: Lockable (anti-accidental operation);
  • EX: Explosion-proof (hazardous environment compatible).
• Voltage: 12DC/24DC/24AC/120AC/220DC/230AC (AC=alternating current, DC=direct current).
• Contact Configuration:
  • 2X21: 2 groups of changeover contacts (1NO+1NC per group);
  • 4X21: 4 groups of changeover contacts.
• Special Suffix:
  • AU: Special normally open contact (enhanced load capacity);
  • EX: Explosion-proof certification.

IV. 3-Step Quick Selection Technique

Step 1: Confirm Power Supply Voltage

• Automation systems: 24DC (most models, e.g., 2903677, 1032527) or 24AC (2903686);
• Mains power (Europe/Asia): 230AC (e.g., 1032529, 2903688) or 220DC (e.g., 2903682);
• North American market: 120AC (e.g., 2903687);
• Low-voltage systems: 12DC (e.g., 2903676, 1109557).

Step 2: Select Contact Quantity

• Dual-circuit switching: 2X21 (e.g., 1032528, 1109554);
• Multi-circuit switching: 4X21 (most IR4 models, e.g., 2903677, 2909738).

Step 3: Choose Special Functions

• Inductive loads (motors/solenoids): LDP suffix (e.g., 2903677, 2903682) for surge protection;
• Critical circuits: Lockable (L suffix, e.g., 1032531) or AU special contacts (e.g., 2903675);
• Hazardous environments: EX suffix (e.g., 2909738, 2909742);
• Dual-polarity control: DP suffix (2905728);
• Basic switching (cost-sensitive): Simplified IRW/IRG series (2960313, 2960261).

V. Recommended Industry-Scenario Combinations

VI. Selection Pitfall Avoidance Guide

1. Surge protection neglect: Inductive loads using non-LDP models → Select LDP suffix (2903677) to suppress voltage spikes.
2. Voltage mismatch: 24DC system using 230AC models → Confirm voltage (AC/DC + value) to prevent relay burnout.
3. Contact quantity insufficiency: 4-circuit needs using 2X21 models → Choose 4X21 (e.g., 2903677) for multi-circuit switching.
4. Explosion-proof requirement missing: Hazardous environments using standard models → Select EX suffix (2909738) for Zone 2 compliance.
5. Lockable function oversight: Critical circuits without L suffix → Use L-lockable models (1032531) to prevent accidental operation.
6. Dual-polarity compatibility error: Bidirectional control using single-polarity models → Choose DP suffix (2905728).
7. Regional voltage incompatibility: North American projects using 230AC models → Select 120AC (2903687) for local mains compatibility.

Conclusion: Select the Right REL-IR Relay for Stable Industrial Control

The Phoenix REL-IR series provides targeted solutions for general switching, inductive load protection, explosion-proof environments, and critical control circuits. With wide voltage compatibility, flexible contact configurations, and special function integration, it adapts to diverse industrial scenarios