Honeywell FA-PSU-UNI2450U v2.1 Safety Manager Power Supply

Honeywell FA-PSU-UNI2450U v2.1 Safety Manager Power Supply (24VDC / 50A, ATEX)

The Honeywell FA-PSU-UNI2450U v2.1 is a universal power supply unit engineered specifically for Honeywell Safety Manager and Fail Safe Control (FSC) architectures. Designed to provide uninterrupted, clean direct current under hazardous, offshore, and harsh process conditions, this unit delivers up to 50A continuous nominal current at 24VDC (field-selectable to 25VDC or 28VDC via internal DIP switches to compensate for long-distance line drops in marine instrumentation loops).

Unlike commercial industrial switched-mode power supplies, the FA-PSU series is designed for SIL 3 mission-critical functional safety loops, featuring redundant architecture support, active load sharing, integrated decoupling diodes, hardware overvoltage protection (OVP), and an ATEX/IECEx certified design with conformal coating for Class I, Division 2 / Zone 2 environments.

Model Details

• Model Number: FA-PSU-UNI2450U
• Hardware Revision: v2.1
• Manufacturer Part Number (MPN): FA-PSU-UNI2450U / 51454475-100 (Equivalent series / revision baseline)
• Standard Industrial Cross-Reference: Honeywell FC-PSU-UNI2450U (Non-ATEX / Standard cabinet version)
• Conformal Coating Version: FA-PSU-UNI2450U-CC / FC-PSU-UNI2450U-CC
• Related Chassis Fan Assembly: FC-FANWR-24R

Features

1. Engineered for Hazardous Locations (Zone 2 / Div 2): Fully certified to ATEX and IECEx standards with non-sparking design, robust mechanical shielding, and ISA G3-compliant conformal coating against corrosive offshore atmospheres (H₂S, SO₂, salt mist).
2. High Output Capability & Redundancy: Delivers continuous rated output (48A at 25VDC; 43A at 28VDC) with passive/active parallel current-sharing circuitry and internal diode decoupling for true N+1 redundant installations.
3. Dual Hardware Overvoltage Protection (OVP): Built to comply with rigorous DIN V 19250 and VDE V 0801 safety regulations, utilizing independent dual hardware shutdown circuits that clamp output overvoltage below 27V (in 25V mode) or 30V (in 28V mode) to prevent downstream DCS/SIS board failure.
4. Marine & Extreme Temperature Rating: Ruggedized topology capable of continuous operation up to +70°C ambient with predictable thermal derating (30W/°C above +50°C) and hot-swappable installation mechanics.
5. Comprehensive Diagnostic Telemetry: Includes a dry-contact undervoltage alarm relay (<22VDC threshold), active front-panel status LEDs (normal operation, thermal warning, overvoltage trip), and fan RPM tracking for proactive maintenance.

Compatibility

• Honeywell Safety Manager: Safety Controller racks, Controller Interface Modules (CPUIO), and Communication Modules.
• Honeywell Fail Safe Control (FSC): Legacy and upgraded FSC 100/101 central processing units and safety racks.
• Honeywell Safety I/O Assemblies: Digital Input Modules (FC-SDIL-1608, SDI-1624), Digital Output Modules (SDO-0824), and Hart Analog Modules (FC-SAI-1620M, CC-PAIH01).
• Field Marshalling Systems: Remote field power distribution racks, intrinsically safe barriers, and safety solenoid valves requiring continuous 24VDC bus integrity.

Frequently Asked Questions

What is the primary difference between Honeywell FC-PSU-UNI2450U and FA-PSU-UNI2450U?

The FC-PSU-UNI2450U is designed for safe industrial environments, whereas the FA-PSU-UNI2450U version is ATEX and IECEx certified for use in hazardous areas (Zone 2 / Class I, Division 2) when installed within an IP54 enclosure. Both share the same fundamental electrical ratings (24VDC/50A).

Can I set the FA-PSU-UNI2450U to output standard 24VDC instead of 25VDC or 28VDC?

The internal regulation of the unit provides 25VDC as standard to overcome inherent drops across internal decoupling diodes and rack backplanes. At the safety controller backplane, this results in a stable 24VDC distribution rail.

What are the wire gauge requirements for the high-current DC output terminals?

The unit utilizes Phoenix Contact PCV6-16 connectors. To safely carry the 50A continuous load without dangerous thermal rise, use stranded copper cabling with a cross-section of 10 mm² to 16 mm² (AWG 8 to AWG 6) and a strip length of 12 mm.

How does the undervoltage alarm relay work on the FA-PSU-UNI2450U?

The 3-pole alarm connector provides a volt-free contact that monitors output rail integrity. Under normal operating voltages (>22VDC), the relay is held energized. If the output drops below 22VDC or input power fails, the relay drops out, signaling the Safety Manager diagnostic subsystem to raise an alarm.

Is this unit compatible with both 110VAC and 230VAC inputs without setting manual switches?

Yes. The power supply features a universal wide-range switch-mode input (93 to 253 VAC, 47–63 Hz) with automatic voltage sensing, eliminating the need for manual transformer taps or selector switches.