Phoenix REL-MR- 4,5DC/21 Single Relay
The Phoenix REL-MR- 4,5DC/21 Single Relay (Part No: 2961367 ) offers a 4.5 V DCnominal input voltage UN, 2.7 V DC ... 12.4 V DC input voltage range, 250 V AC/DC switching voltage, Plug / solder 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-MR- 4,5DC/21 |
Phoenix REL-MR- 4,5DC/21 Single Relay – Technical Specifications
| Specification | Value |
|---|---|
| Product type | Single relay |
| Mechanical service life | 2x 107 cycles |
| Overvoltage category | III |
| Pollution degree | 3 |
| Maximum power dissipation for nominal condition | 0.17 W |
| Test voltage (Winding/contact) | 4 kV AC (50 Hz, 1 min., winding/contact) |
| Nominal input voltage UN | 4.5 V DC |
| Input voltage range | 2.7 V DC ... 12.4 V DC |
| Drive and function | monostable |
| Drive (polarity) | non-polarized |
| Typical input current at UN | 38 mA |
| Typical response time | 5 ms |
| Typical release time | 2.5 ms |
| Contact switching type | 1 changeover contact |
| Type of switch contact | Single contact |
| Contact material | AgSnO |
| Maximum switching voltage | 250 V AC/DC |
| Minimum switching voltage | 5 V (at 100 mA) |
| Limiting continuous current | 6 A |
| Maximum inrush current | 10 A (4 s) |
| Min. switching current | 10 mA (at 12 V) |
| Interrupting rating (ohmic load) max. | 140 W (at 24 V DC) |
| Connection method | Plug / solder connection |
| Width | 5 mm |
| Height | 28 mm |
| Depth | 15 mm |
| Degree of protection | RT III |
| Ambient temperature (operation) | -40 °C ... 85 °C |
| Ambient temperature (storage/transport) | -40 °C ... 85 °C |
| Standards/regulations | IEC 60664 |
| Mounting position | any |
| Coil resistance | 119 Ω ±10 % (at 20 °C) |
| Switching capacity | 2 A (at 24 V, DC13) |
| Motor load according to UL 508 | 1/4 HP, 240 - 277 V AC (N/O contact) |
The Phoenix Contact REL-MR-4,5DC/21 (Part No: 2961367) offers precision control in compact environments, operating efficiently at a nominal input voltage of 4.5 V DC with a wide input voltage range of 2.7 V DC to 12.4 V DC. It draws a typical input current of 38 mA and responds quickly within 2.5 milliseconds, enabling rapid switching performance for low-power automation circuits.
This Single Relay is built with AgSnO contact material and a single changeover contact, capable of switching up to 250 V AC/DC. Its compact design supports a continuous current load of 6 A and manages maximum inrush currents of up to 10 A for 4 seconds. The relay’s mechanical life of 20 million cycles ensures long-term performance, while the plug/solder connection makes installation straightforward in control panels. Rated with RT III protection and compliant with IEC 60664, it is built to perform in extreme industrial temperatures from -40 °C to +85 °C.
Industrial professionals rely on the REL-MR-4,5DC/21 for its stable switching behavior and compact width of 5 mm, making it ideal for terminal blocks, interface relays, and space-restricted automation cabinets. To explore more models, visit the Phoenix Relay product section or view the Phoenix Contact brand page.
Thanks to its 4.5 V DC input voltage capability and fast 2.5 ms switching response, this relay is highly dependable for logic-level control and time-sensitive relay automation. The plug/solder terminals simplify quick mounting in PCB assemblies or relay sockets, making it a go-to choice for OEM machine builders and automation panel designers who require compact, durable relays with high electrical endurance.
For students and junior automation engineers, the REL-MR-4,5DC/21 demonstrates how low-voltage signal switching works in real-world applications. It provides hands-on exposure to voltage matching, contact load calculations, and relay selection in both resistive and inductive circuits. Its proven reliability across industrial setups makes it both a learning tool and a professional solution.
