Technical Specifications:

• Output Voltage: 24 V DC (regulated)
• Output Power: 50 W maximum
• Output Current: 2.08 A maximum (50 W / 24 V)
• Input Voltage: 100–240 V AC, 50/60 Hz (universal input)
• Redundancy Type: Dual-input redundant (RPS — Redundant Power Supply)
• Output Ripple: Less than 100 mV peak-to-peak
• Efficiency: Greater than 80% at full load
• Operating Temperature Range: -20°C to +70°C (-4°F to +158°F)
• Protection Rating: NEMA 4X / IP66 (front panel and enclosure)
• Hazardous Area Approvals: ATEX Zone 1/2, Division 1/2 (Class I, II, III)
• IECEx Certified: Yes
• Safety Integrity Level: SIL 2 (IEC 61508)
• Dimensions (W × H × D): Approximately 120 mm × 150 mm × 110 mm
• Weight: Approximately 1.5 kg
• Mounting: DIN rail (TS 35/7.5 or TS 35/15)

Functional Features:

• Redundant AC input — automatic switchover within 20 ms on primary failure
• DC output filtering for noise-sensitive field instruments
• Overcurrent protection with automatic reset
• Overvoltage protection with crowbar circuit
• LED status indicators for input power, output power, and fault conditions
• Remote alarm contact for power failure notification
• Inrush current limiting to protect upstream circuits

Structural Characteristics:

• Die-cast aluminum enclosure with corrosion-resistant epoxy coating
• DIN rail mountable
• Screw-terminal connections for AC input and DC output
• Transparent cover for LED status visibility

Working Principle:
The NFPW426-50 accepts 100–240 V AC input and converts it to a stable 24 V DC output using a high-frequency switch-mode power supply (SMPS). The redundant design uses two independent AC-DC converters with automatic transfer logic. When the primary AC source fails, the backup converter takes over within 20 milliseconds, ensuring zero interruption to field instruments. The output is filtered to reduce electromagnetic interference (EMI) that could affect HART or Fieldbus communications.

Advantages:

• 20 ms switchover time — field instruments experience no power interruption
• 50 W capacity supports multiple field devices on a single unit
• Universal AC input (100–240 V) eliminates need for transformer selection
• Hazardous area certified (ATEX/IECEx) for Zone 1 and Zone 2 installation
• SIL 2 rated for safety-critical applications

Applicable Industries:

• Oil and Gas (Onshore and Offshore)
• Chemical and Petrochemical Plants
• Power Generation and Distribution
• Water and Wastewater Treatment
• Mining and Mineral Processing

Installation Requirements:

• Mount on DIN rail inside a control cabinet or marshalling cabinet
• Provide dedicated AC circuit breaker (2 A to 5 A) for each power supply
• Connect both AC inputs to separate power sources for true redundancy
• Keep minimum 50 mm clearance above and below for ventilation
• Ground the enclosure to the plant grounding system

Precautions:

• Do not connect the output to a load exceeding 2.08 A (50 W)
• Verify both AC inputs are connected to different sources for redundancy to function
• Do not operate in ambient temperatures exceeding +70°C
• Ensure the input fuse rating matches the local electrical code (typically 2 A to 5 A)