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Phoenix REL-IR4/LDP- 24DC/4X21 Single Relay
The Phoenix REL-IR4/LDP- 24DC/4X21 Single Relay (Part No: 2903677 ) offers a 24 V DCnominal input voltage UN, 18.7 V DC ... 46.8 V DC (20 °C) input voltage range, 250 V AC/DC switching voltage, Plug-in connection method. Manufactured by Phoenix under the Phoenix Single Relay category, this model belongs to the Phoenix REL Series.
| Brand | Phoenix Contact |
| Product Type | Single Relay |
| Model Number | REL-IR4/LDP- 24DC/4X21 |
Phoenix REL-IR4/LDP- 24DC/4X21 Single Relay – Technical Specifications
| Specification | Value |
|---|---|
| Product type | Single relay |
| Mechanical service life | approx. 2x 107 cycles |
| Insulation | Basic insulation |
| Overvoltage category | II |
| Pollution degree | 2 |
| Service life electrical | see diagram |
| Maximum power dissipation for nominal condition | 1.01 W |
| Test voltage (Winding/contact) | 2.5 kVrms (50 Hz, 1 min., winding/contact) |
| Test voltage (Changeover contact/changeover contact) | 2 kVrms (50 Hz, 1 min., changeover contact/changeover contact) |
| Rated insulation voltage | 250 V AC |
| Rated surge voltage | 2.5 kV |
| Nominal input voltage UN | 24 V DC |
| Input voltage range | 18.7 V DC ... 46.8 V DC (20 °C) |
| Drive and function | monostable |
| Drive (polarity) | polarized |
| Typical input current at UN | 42 mA |
| Typical response time | 14 ms |
| Coil voltage | - |
| Status display | LED (yellow) |
| Contact switching type | 4 changeover contacts |
| Type of switch contact | Single contact |
| Contact material | AgNi |
| Maximum switching voltage | 250 V AC/DC |
| Minimum switching voltage | 5 V (At 24 mA) |
| Limiting continuous current | 6 A |
| Maximum inrush current | 16 A (20 ms, N/O contacts) |
| Min. switching current | 5 mA (at 24 V) |
| Interrupting rating (ohmic load) max. | 144 W (at 24 V DC) |
| Connection method | Plug-in connection |
| Width | 21.2 mm |
| Height | 27.5 mm |
| Depth | 35.6 mm |
| Degree of protection | RT I |
| Degree of protection (Installation location) | - |
| Ambient temperature (operation) | -40 °C ... 70 °C |
| Ambient temperature (storage/transport) | -40 °C ... 85 °C |
| Standards/regulations | IEC 60664 |
| Mounting type | - |
| Mounting position | any |
| Mains frequency | - |
| Typical release time range | - |
| Coil resistance | - |
| Switching capacity | 2 A (at 24 V, DC13) |
| Motor load according to UL 508 | 1/3 HP, 240 V AC |
| Input power dissipation for UN | - |
| 3-phase motor load | - |
| Product family | - |
| Relay type | - |
| Test voltage () | - |
| Degree of protection (Relay) | - |
| Inrush current, minimum | - |
| Non-operate voltage | - |
| Safe operate voltage | - |
| Test voltage (N/O contact / N/O contact) | - |
The Phoenix Contact REL-IR4/LDP-24DC/4X21 (Part No: 2903677) is an advanced Phoenix Basic Insulation Single Relay engineered for dependable electrical performance in industrial control panels. It operates at a nominal input voltage of 24 V DC and supports a wide range from 18.7 V DC to 46.8 V DC, ensuring compatibility with diverse control voltages. With a fast 14 ms response time, 42 mA input current, and 4 changeover AgNi contacts, it provides high switching accuracy up to 250 V AC/DC.
Tested to IEC 60664 standards, this Single Relay offers 2.5 kVrms insulation between winding and contact and supports a maximum inrush current of 16 A. Designed with basic insulation and an LED status indicator, it delivers reliable feedback and diagnostic visibility. It achieves a mechanical service life of approximately 2 × 10⁷ cycles, guaranteeing long-term durability in high-frequency switching environments. Its compact 21.2 mm body, plug-in connection, and RT I protection simplify installation in space-limited relay racks and modular automation assemblies.
The Phoenix Contact REL-IR4/LDP-24DC/4X21 is ideal for use in automation cabinets, PLC control systems, process plants, and machine feedback loops. Engineers rely on this Single Relay for dependable switching in HVAC circuits, energy monitoring panels, and signal control modules. Its broad voltage tolerance and robust AgNi contact construction ensure consistent operation in temperature ranges from -40°C to +70°C. With low power dissipation and excellent insulation, it supports long-term performance and electrical safety in industrial and commercial automation environments. Maintenance teams value its quick integration, stable performance, and long lifecycle, making it a preferred relay for OEMs and system designers.
Buyers searching for REL-IR4-LDP-24DC-4X21-2903677, REL-IR4/LDP-24DC/4X21, or 2903677 can rely on the quality and precision of Phoenix Contact 2903677. Known for its performance and reliability, this 2903677 Phoenix relay operates efficiently under demanding conditions. The 2903677 Phoenix Contact version combines safety with strong insulation properties, ensuring stable switching performance in industrial control systems. Built on trusted German engineering, the Phoenix 2903677 and REL-IR4/LDP-24DC/4X21 continue to be preferred by electrical engineers seeking reliability, compactness, and thermal endurance in 24 V DC Single Relay applications.
