Product Core Brief
- Model: 8920-PS-DC
- Brand: GE / MTL Instruments (PAC8000 IS module power supply)
- Series: PAC8000 Intrinsically Safe / Hazardous-Area Power
- Core Function: Supplies regulated 12 VDC to the PAC8000 IS Railbus and powers intrinsically safe I/O modules in hazardous-area PAC8000 nodes.
- Product Type: IS Module Power Supply
- Key Specs: 24 VDC nominal input | 18.5–36 VDC input range | 12 VDC Railbus output | 5 A output capacity | load sharing for redundancy | hazardous-area certified
- Condition: New Original / New Surplus
Key Technical Specifications
- Part Number: 8920-PS-DC
- Product Family: PAC8000 IS Module Power Supply
- Input Voltage: 18.5–36 VDC, nominal 24 VDC
- Input Current Rating: 5 A
- Output Voltage: 12 VDC nominal IS Railbus
- Output Current: 5.0 A at 55°C; 3.0 A at 70°C
- Redundancy: Supports load sharing for redundant power configurations
- Carrier Mounting: 8724-CA-PS type carrier
- Efficiency: About 76–78% depending on input voltage and load
- Ambient Temperature: -40 to +70°C
- Certifications: ATEX / IECEx / Class I, Div 2 hazardous-area approvals as marked on the unit
- Typical Applications: PAC8000 hazardous-area I/O nodes, intrinsically safe analog and discrete I/O power, oil and gas field stations, SafetyNet IS nodes, and remote process I/O racks
Product Introduction (No Fluff)
The GE 8920-PS-DC is an intrinsically safe module power supply for PAC8000 hazardous-area I/O systems. It accepts an 18.5–36 VDC input and delivers a regulated 12 VDC output to the IS Railbus, providing power to intrinsically safe I/O modules mounted in the same PAC8000 carrier assembly.
This power supply supports load sharing, allowing redundant units to improve availability in critical process applications. It is commonly used in PAC8000 nodes installed in hazardous areas, including oil and gas wellheads, compressor stations, process skids, and SafetyNet IS I/O segments. Because it supplies the IS Railbus rather than external field instruments directly, it must be installed in a compatible PAC8000 IS carrier and applied according to the hazardous-area certification documents.
QA & Testing SOP (Dynamic & Transparent)
For an IS power supply module, we verify identification, physical condition, connector integrity, and output readiness before release.
- Part number verification: Confirm 8920-PS-DC on the module label. Record revision, serial number, and certification markings.
- Visual inspection: Check the housing, carrier mounting interface, Railbus connector, input terminals, LEDs, and PCB for corrosion, burn marks, or mechanical damage.
- Input terminal check: Verify the screw terminals are intact, properly rated, and free of oxidation or loose contacts.
- Railbus connector inspection: Inspect the IS Railbus interface for bent pins, contamination, or poor contact.
- Output verification: Where a compatible test setup is available, apply 24 VDC input and confirm the 12 VDC Railbus output is within specification.
- Load sharing check: If redundant units are tested together, verify load-sharing behavior and absence of backfeed faults.
- Certification traceability: Preserve label data, approval codes, and installation drawing references.
- ESD-safe packaging: Ship in anti-static bags with foam protection. Include part number, revision, and inspection status on the label.
Installation Pitfalls & Guide (Engineer to Engineer)
❗ This is an IS Railbus power supply, not a general 24 VDC supply. The 8920-PS-DC provides 12 VDC to the PAC8000 IS Railbus. Do not use it as a substitute for 24 VDC field power supplies such as 8914-PSAC.
❗ Verify hazardous-area certification before installation. The module carries ATEX / IECEx / Class I Div 2 markings, but the allowed installation method depends on the specific certificate and local authority requirements.
❗ Do not mix IS and non-IS power domains. IS Railbus power, field power, and system power must be separated according to the PAC8000 IS node design.
❗ Confirm carrier compatibility. This power supply mounts in a designated PAC8000 IS carrier such as 8724-CA-PS. Installing it in an incompatible carrier can prevent proper Railbus power distribution.
❗ Check derating at high temperature. Output current is reduced at elevated ambient temperatures. Design the node load within the 5.0 A at 55°C and 3.0 A at 70°C limits.
❗ Use redundancy correctly. When load sharing is required, verify that both power supplies are configured for redundant operation and fed from independent sources where applicable.
Replacement steps:
- Pre-install: Record input voltage, Railbus load, redundancy configuration, and hazardous-area installation references.
- Isolate: De-energize the PAC8000 IS node and follow hazardous-area work permits before disconnecting wiring.
- Remove: Release input wiring and remove the power supply from the carrier without forcing the Railbus connector.
- Install: Seat the replacement 8920-PS-DC firmly, restore input wiring with correct polarity, and verify carrier engagement.
- Commission: Measure Railbus voltage, verify module LED status, confirm I/O module power-up, and test redundancy if applicable.
Technical FAQ
What does 8920-PS-DC do?
It converts an 18.5–36 VDC input into a regulated 12 VDC IS Railbus supply for PAC8000 intrinsically safe I/O modules.
Is it a 24 VDC field power supply?
No. It supplies the IS Railbus. External 24 VDC field power for certain PAC8000 / SafetyNet modules is provided by separate power units.
Can it be used redundantly?
Yes. It supports load sharing for redundant power configurations.
What is the output current rating?
Up to 5.0 A at 55°C and 3.0 A at 70°C, depending on ambient temperature and node loading.
Where is it typically used?
In PAC8000 hazardous-area I/O nodes, including oil and gas, process safety, and SafetyNet IS applications.
