Description
Product Introduction & Engineering Value
The FPS400-24 P0922YU is the standard 400 W power supply qualified by Foxboro for use with 200 Series Fieldbus Modules and baseplates. It accepts a wide-range AC or DC input (85–265 V AC at 47–63 Hz, or 108–145 V DC) and delivers a tightly regulated 24.0 V DC output.
High efficiency (typically 85–92 % depending on input voltage), power-factor correction, dual-stage current limiting, and overvoltage shutdown protect both the supply and the connected modules. The unit is convection-cooled (no fans), housed in a gasketed extruded-aluminum enclosure, and certified for Class I, Division 2 and Zone 2 applications. A form-C relay alarm contact provides status feedback to the control system.
Technical Specifications
| Parameter | Value |
|---|---|
| Output Voltage | 24.0 V DC ±0.2 V (factory set) |
| Maximum Output Power | 400 W |
| Maximum Output Current | 16.7 A |
| Input Voltage Range (P0922YU) | 85–265 V AC or 108–145 V DC |
| Input Frequency | 47–63 Hz |
| Efficiency | 77 % min at 85 V AC; ~85 % at 120 V AC; ~92 % at 230 V AC |
| Inrush Current | 20 A peak at 110 V AC; 40 A peak at 220 V AC (cold start) |
| Cooling | Convection (fanless) |
| Protection | Dual-stage current limiting, overvoltage shutdown (~28 V), internal fuse |
| Isolation | 3000 V AC input-to-output; 1500 V AC input-to-chassis; 500 V AC output-to-chassis |
| Alarm | Form-C relay status contact |
| Environmental Rating | ISA Class G3; Div 2 / Zone 2 certified |
| Mounting | DIN rail (horizontal or vertical), bracket, or wall |
Field Application & The “Trench” Experience
A Midwest refining site expanded a remote DIN-rail FBM cabinet that previously suffered from marginal 24 V power under full load. An FPS400-24 P0922YU was installed on the DIN rail with proper clearances for convection cooling. The wide-range input accepted the local 120 V AC feed without transformers. After connection to the baseplate power bus and verification of the alarm contact, the cabinet ran at full FBM load with stable 24 V and no thermal issues. The fanless design eliminated a previous maintenance concern with failing cooling fans.
Typical niche applications:
- Primary or redundant 24 V power for standard 200 Series FBM baseplates in process cabinets
- Powering mixed FBM, FCM, and FCP loads in remote or field-mounted enclosures
- Installations requiring Div 2 / Zone 2 certification and G3 environmental capability
FPS400-24 P0922YU
FPS400-24 P0922YU
Transparency SOP: QA & Testing
Each unit is powered across its full input voltage range while output voltage, regulation, and ripple are measured under varying loads up to rated capacity. Current-limit and overvoltage protection thresholds are verified. The form-C alarm contact is exercised. Thermal performance is confirmed during an elevated-temperature soak at rated load. Only units that meet the original specifications are released.
The Veteran’s Tech Trap Guide
⚠️ Observe convection clearances. The FPS400-24 is fanless. Insufficient free air space above and below the unit will cause thermal derating or premature shutdown under high ambient temperatures or full load.
PRO TIP: When paralleling multiple supplies for redundancy or higher capacity, follow the Foxboro guidelines for diode isolation or specific parallel wiring. Direct paralleling without proper current sharing can lead to uneven loading and nuisance trips.
⚠️ Input voltage and derating. At lower input voltages or higher ambient temperatures the available output power is reduced. Always check the derating curves for the actual plant conditions before loading the supply to its nominal 400 W rating.
Dynamic FAQ
Q: What input voltages does the FPS400-24 P0922YU accept? A: 85–265 V AC (47–63 Hz) or 108–145 V DC (125 V DC nominal).
Q: What is the maximum continuous output? A: 24 V DC at up to 16.7 A (400 W), subject to input voltage and ambient temperature derating.
Q: Is this power supply qualified for 200 Series FBMs? A: Yes. The FPS400-24 series is the only power supply family tested and qualified by Foxboro for use with standard 200 Series Fieldbus Modules and baseplates.
Q: Does the unit have status indication or alarm contacts? A: Yes. A form-C relay contact provides power-supply status to the control system.
Q: Are New Surplus FPS400-24 P0922YU units original Foxboro product? A: Yes. Units are original OEM material that have passed full electrical, protection, and thermal testing.
Q: What warranty is provided? A: 12-month warranty against defects in materials and workmanship from the date of shipment for both New Surplus and fully tested refurbished units.
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