Description
Product Introduction
The 531X121PCRALG1 is the ultimate power supply for the Mark V system—delivering the absolute highest hold-up time of any Mark V power supply ever produced. With 190ms of hold-up and the full suite of diagnostic capabilities, it’s the supply you install when power continuity is the single most critical factor in your turbine control system.
Compared to the 531X121PCRALG (non-1 revision), the “G1” version adds active power factor correction (upgraded from 0.95 to >0.99), extended hold-up from 50ms to 190ms, a modular fan cartridge with ball-bearing fans, and diagnostic data logging with USB download. The terminal assignment is identical—direct drop-in. No firmware changes required.
Key Technical Specifications
| Parameter | Value / Range |
|---|---|
| AC Input Voltage | 200–240 VAC ±10% (no 120V operation) |
| Input Frequency | 47–63 Hz |
| Input Current (Max) | 9.0 A @ 240VAC |
| Power Factor | >0.99 (active PFC) |
| Inrush Current (Cold Start) | 23A peak @ 240VAC |
| DC Output Voltage | 24 VDC ±1% (fixed) |
| Remote Sense Compensation | Up to 2.5V drop (adjustable) |
| Output Current (Continuous) | 66.6 A (1600W) |
| Output Current (Peak, 10s) | 80.0 A |
| Hold-up Time | 190 ms @ full load |
| Ripple & Noise | < 50 mV p-p |
| Efficiency | 96% typical |
| Protections | Overvoltage, overcurrent, overtemperature, short-circuit |
| Redundancy | Parallel operation with OR-ing diodes + hardware load-sharing |
| Load-Sharing Accuracy | ±1% |
| Diagnostic Output | RS-485 (Modbus RTU) – 30+ registers |
| Data Logging | 10,000 fault events (time-stamped) |
| Log Download | USB Type B |
| Status Indicators | DC OK, Fault, Overload, Fan, Load Share, Remote Sense, Diagnostic, Data Log Full, USB Active |
| Cooling | Modular fan cartridge (dual 92mm ball-bearing fans, 50 CFM) |
| Fan Replacement | Swap entire cartridge—no individual fan replacement |
| Termination | Screw terminal (input) + 24-pin backplane + 2-pin remote sense + 3-pin RS-485 + USB Type B |
| Operating Temp | 0°C to +60°C |
| Dimensions | 280 x 120 x 85 mm |
Compatible Replacement Models
| Model | Classification | Notes |
|---|---|---|
| 531X121PCRALG1 | ✅ Drop-in Replacement | Target model. No changes. |
| 531X121PCRALG | ✅ Drop-in Replacement | Original revision—0.95 PFC, 50ms hold-up, no diagnostics. Direct swap. |
| 531X121PCRAKG1 | ✅ Drop-in Replacement | 1600W, 180ms hold-up, 10,000-event log. Direct swap—the ALG1 has longer hold-up. |
| 531X121PCRAJG1 | ✅ Drop-in Replacement | 1600W, 170ms hold-up, 10,000-event log. Direct swap—the ALG1 has longer hold-up. |
| 531X121PCRAHG3 | ✅ Drop-in Replacement | 1600W, 165ms hold-up, 10,000-event log. Direct swap—the ALG1 has longer hold-up. |
| 531X121PCRAGG3 | ✅ Drop-in Replacement | 1600W, 160ms hold-up, 10,000-event log. Direct swap—the ALG1 has longer hold-up. |
| 531X112PSAAMG1 | ✅ Drop-in Replacement | 1600W, 160ms hold-up, 10,000-event log. Direct swap—the ALG1 has longer hold-up. |
| DS3800NPSA | ❌ Hardware Incompatible | Mark IV supply—different form factor. |
Frequently Asked Questions (FAQ)
Q: What’s the difference between the ALG1 and the AKG1?
The ALG1 has the longest hold-up in the Mark V power supply family (190ms vs. 180ms) and the lowest inrush current (23A vs. 24A). Both have 10,000-event logs and the full diagnostic suite. The ALG1 is the absolute top-spec version ever produced—if you need the maximum hold-up time available for the Mark V system, this is the supply you want.
Q: The Fault LED is red, but the DC OK LED is green. What’s happening?
Green DC OK means the 24V output is within spec. Red Fault indicates an internal warning—typically overtemperature (fan failure) or input voltage out of range. The data logger captures the fault, and the USB port allows quick log download for analysis. The diagnostic registers provide detailed fault type information.
Q: Can I run two ALG1 supplies in parallel for redundancy?
Yes—the ALG1 has OR-ing diodes and hardware load-sharing. Connect DC outputs together (+24V to +24V, 0V to 0V), connect load-share signal terminals together, connect remote sense terminals together, connect RS-485 terminals together (daisy-chain), and feed AC inputs from separate breakers. The supplies share the load within ±1%. Each supply has its own data log.
Q: Can I hot-swap the ALG1 while the rack is powered?
Yes, in redundant configurations (two supplies in parallel). In a single-supply config, pulling the supply shuts down the rack. If redundant, verify the OR-ing diodes are present before pulling one. The remote sense and load-sharing circuits automatically re-balance when you insert a new supply.
Q: What’s the expected lifespan of the ALG1?
The electrolytic capacitors are rated for 12,000 hours at 85°C. In a 40°C cabinet, the lifespan extends to about 18-22 years. The modular fan cartridge with dual ball-bearing fans is rated for 80,000 hours at 40°C (about 9.1 years). Replace the fan cartridge every 5-7 years proactively.
Q: What’s the lead time for a surplus unit?
We keep 2-3 units in stock. Domestic: 2-3 business days ground, overnight if ordered by 2 PM EST. International: 5-7 days via DHL, with customs potentially adding 1-3 days. We include a GE certificate of origin and commercial invoice with every shipment. Contact us if you need expedited shipping.


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