Description
Technical Parameters
| Parameter | Specification |
|---|---|
| Input Voltage | 125 VDC nominal (range 100–150 VDC); 24 VDC compatible with external adapter |
| Input Redundancy | Dual independent inputs with automatic failover (diode‑ORed) |
| Output Rails | +24 VDC / 8A (field power), ±15 VDC / 1A (analog field circuits), +5 VDC / 2A (logic/communication) |
| Isolation | Full isolation (1.5kV input‑to‑output, 2.0kV output‑to‑ground) |
| Protection | Individual overcurrent protection per output (adjustable), short‑circuit protection, transient suppression (4kV), reverse polarity protection, input undervoltage lockout |
| Regulation | Load regulation: ±0.3%; Line regulation: ±0.15%; Ripple: < 30mVpp (+24V), < 15mVpp (±15V), < 20mVpp (+5V) |
| Monitoring | 4 analog feedback channels (voltage and current monitoring for +24V and ±15V outputs); 3 digital fault outputs (relay, 24V/1A) for individual output faults, input failover, and system health |
| Digital Interface | 2 digital inputs for external enable/disable; 4 digital outputs for output status indication |
| Operating Temperature | –25°C to +60°C |
| Form Factor | 6U × 6HP (30mm) – requires 1.5 slots |
| Backplane Connector | Standard VME 96‑pin P1 + reinforced 60‑pin P2 (for second input and high‑current outputs) |
| Status LEDs | 8 indicators: INPUT 1 OK (green), INPUT 2 OK (green), +24V OK (green), ±15V OK (green), +5V OK (green), FAULT (red), OVERTEMP (yellow), FAILOVER ACTIVE (amber) |
| Certifications | CE, UL 508, CSA Class I Div 2 |
| Efficiency | ~83% at full load |
Critical note: The DS3800NRFA is a redundant field power interface designed for critical field device power distribution. It provides dual input failover and individual output protection for field devices. This board is physically wider (6HP) than standard 4HP boards and requires 1.5 adjacent slots. Hot‑swapping is not supported.
Key Features & Advantages
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Redundant Field Power – The DS3800NRFA accepts two independent 125VDC inputs with automatic failover, ensuring uninterrupted power to critical field devices during input loss.
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Individual Output Protection – Each output (+24V, ±15V, +5V) has independent overcurrent protection with adjustable thresholds, preventing a fault on one output from affecting others.
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Comprehensive Monitoring – Four analog feedback channels provide voltage and current telemetry for the +24V and ±15V outputs, enabling remote monitoring of field power health.
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Three Fault Relays – Three form‑C relay contacts (24V/1A) provide separate fault indication for output faults, input failover events, and system health.
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Full Isolation – 1.5kV isolation protects sensitive control circuits from field device transients and ground loops.
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Dual Input Status – Digital outputs provide active status indication for each input, allowing remote monitoring of which input is currently supplying power.
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Wide Temperature Range – Extended –25°C to +60°C range and CSA Div 2 certification make the DS3800NRFA suitable for demanding environments.
Typical Application Cases
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Critical Solenoid Valve Power – Provides redundant, conditioned power to safety shutdown solenoids, trip valves, and purge valves.
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Actuator Control Panels – Powers electric actuators for inlet guide vanes, bleed valves, and turbine bypass controls.
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Field Transmitter Power – Supplies power to pressure transmitters, temperature sensors, and positioners in critical measurement loops.
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Redundant Field Device Cabinets – Installed in auxiliary panels where field device power continuity is essential.
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Offshore Platforms – Dual input capability supports connection to two independent battery banks.
Competitive Comparison
| Aspect | DS3800NRFA (GE) | DS3800NPSL1A1A (GE) | Generic Redundant Field Supply |
|---|---|---|---|
| Primary Output | +24V / 8A | 125VDC / 5A | +24V / 10A |
| Input Redundancy | Yes | No | Yes |
| Individual Output Protection | Yes (3 outputs) | No (single output) | Varies |
| Monitoring Channels | 4 (V + I) | 1 (V only) | Varies |
| Fault Relays | 3 | 1 | Varies |
| Form Factor | 6HP (1.5 slots) | 8HP (2 slots) | Standalone |
| Price (refurb) | ~$4,500–$6,500 | ~$2,800–$4,200 | ~$800–$1,500 |
The DS3800NRFA is the premier redundant field power interface in the DS3800 family, offering dual input failover, individual output protection, and comprehensive monitoring.
Selection Guidelines & Precautions
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Application Verification – The DS3800NRFA is designed for critical field device power distribution. Verify that your application requires redundant field power with individual output protection.
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Physical Compatibility – The DS3800NRFA is 6HP wide, requiring 1.5 adjacent slots. It will not fit in standard 4HP slots.
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Backplane Compatibility – Uses both P1 and reinforced P2 connectors. The second DC input is provided through P2. If your backplane lacks P2, the redundant input feature will be unavailable.
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Protection Threshold Adjustment – Configure overcurrent thresholds via onboard jumpers (JP1–JP3) based on field device requirements.
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Thermal Derating – Full output available up to 50°C:
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50°C–55°C: derate all outputs to 90% of rated current
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55°C–60°C: derate all outputs to 80% of rated current
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Above 60°C: do not operate
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Spare Sourcing – Production ended in 2015. Request a load test report verifying all outputs at rated current and failover functionality. Visually inspect for capacitor bulging or discoloration.
A-B 1756-TBNH
A-B 1769-ECR
A-B 1769-ECR
SCHNEIDER GV3D22
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