AX5-33 50 VDC Power Shelf | 33 kW in 1 OU for ORv3
3-Phase AC to 50 VDC Power Shelf / ORv3 AI Rack Infrastructure (21″)
Deliver high-efficiency 50 VDC power from single- or three-phase AC sources for AI and accelerated computing environments.
AX5-33 50 VDC Power Shelf
Deliver high-efficiency 50 VDC power from single- or three-phase AC sources for AI and accelerated computing environments. AX5-33 converts AC directly to regulated 50 VDC at the rack, eliminating server-level AC-DC conversion and simplifying rack power design.
per 1 OU shelf
adjustable
4 shelves in parallel
peak
AC or DC to 50 VDC power at the rack
The AX5-33 Power Shelf is a high-density conversion platform designed for GPU clusters, AI compute, and ORv3 rack deployments. Using six 5.5 kW hot-swappable modules, AX5-33 provides up to 33 kW of continuous 50 VDC output in a compact 1 OU form factor.
AX5-33 accepts either 346–480 VAC three-phase wye (4W + G) or 180–400 VDC at 240 VDC nominal, at full rating on either, and delivers tightly regulated 50 VDC output with flexible redundancy. The integrated PMC control architecture enables system-level monitoring and coordinated operation across parallel shelves, while the modular BBU system provides scalable ride-through capability. Multiple shelves can be deployed in parallel to support AI rack power systems up to 132 kW.
Built for high-density AI rack power
Compact AC-DC shelf for AI and GPU rack deployments, without consuming valuable rack space.
Six hot-swappable PSUs scale capacity in 5.5 kW increments within each shelf.
Designed for Open Compute 21″ rack environments and high-density rack architectures.
Supports N+0, N+1, and N+N configurations to match availability requirements.
Modules can be added or serviced without interrupting operation for continuous uptime.
System-level monitoring, communication, and coordination across shelves over Modbus and CAN.
Scalable ride-through from a hot-swappable BBU shelf, integrated with PMC monitoring.
Deploy up to four paralleled AX5-33 shelves for rack power systems up to 132 kW.
Rack-level DC delivery in the Xtreme Power portfolio
AX5-33 operates as a rack-level AC-to-DC power platform, delivering 50 VDC directly to IT equipment. It is selected when rack-level DC delivery and a simplified power architecture are prioritized.
AC distribution to racks — conventional rack power for standard IT loads.
AC to 50 VDC conversion at the rack, removing server-level AC-DC stages.
Centralized 800 VDC architectures for facility-scale distribution.
Technical specifications
| Capacity | |
|---|---|
| System capacity | 33 kW (N+0) / 27.5 kW (N+1) / 16.5 kW (N+N) |
| Module rating | 5.5 kW (PSU5-55) |
| Integrated capacitance | 120 J per module — AI load smoothing plus 20 ms hold-up to bridge to the battery shelf |
| Input | |
| Shelf, three-phase | 346V to 480V, three-phase wye, 4W + G |
| Shelf, single-phase | 200V to 277V nominal (2W + PE), range 180V to 305V |
| PSU | 200 / 208 / 220 / 240 / 277 V nominal single-phase, range 180V to 305V |
| DC input | 180V to 400V DC (240V nominal); start-up 180V, power off 175V |
| Input configuration | Two AC inputs, three PSU positions on each; 2 × 30A NEC or 32A IEC, one per input. Single-input variant also available |
| Output | |
| Voltage | 50 VDC (adjustable) |
| Current | 113 A per module; 678 A maximum per shelf |
| Current sharing | Active and droop |
| Power module | |
| Power rating | 5.5 kW per PSU5-55 module |
| Hot swap | Yes |
| Efficiency | Up to 97.5% |
| Communication & control (PMC) | |
| Function | Aggregates module data and enables system-level monitoring and control |
| Protocols | RS485 Modbus (rack-level), CAN (inter-shelf) |
| Addressing | Automatic Modbus and CAN address allocation across shelves |
| Protocols | RS485 Modbus slave over 8-pin RJ45; CAN for inter-shelf control |
| Connectivity | 4 × RJ45 (daisy-chain and inter-shelf control) |
| Scalability | Coordinated operation across parallel AX5-33 and BBU shelves |
| Serviceability | Hot-swappable with firmware upgrade support (no power interruption) |
| Modular battery backup (BBU) | |
| Type | Modular battery shelf (2 OU) |
| Power | Up to 33 kW per shelf |
| Runtime | >90 sec @ 5.5 kW · >240 sec @ 4 kW |
| Scalability | Parallel shelf capable |
| Service | Hot-swappable modules |
| Control | Intelligent BMS, Modbus |
| Environmental | |
| Operating temperature | −5°C to +45°C (23°F to 113°F) |
| Storage temperature | −40°C to +85°C |
| Humidity | 10 to 90% operating, non-condensing |
| Operating altitude | 3050 m (10,000 ft); 12,000 m non-operating |
| Shock & vibration | EN 60068-2-6 and 60068-2-27; 12 g / 1 g non-operating, 6 g / 0.5 g operating |
| Acoustic noise / airflow | Target not to exceed 85 dBA with fans at full speed (design target, not a measured figure). Front-to-back, speed-controlled; 12 °C (22 °F) nominal rise across 30 to 85% load |
| Mechanical | |
| Dimensions (W×D×H) | 21 × 28.3 × 1.8 in (537 × 720 × 46 mm) |
| Rack compatibility | ORv3 (21″) |
| Shelf connectors | Amphenol 10173750-07P01 input; FCI BarKlip BK600 10164745-1SP092LF output |
| System architectures | |
| Direct 50 VDC | AC → AX5-33 → 50 VDC load |
| 800 VDC | AC → AX8 → DX8 → 50 VDC load |
| Parallel operation | |
| Scaling | Up to 4 shelves / 132 kW total |
| Compliance | |
| EMC | EN 61000-4-2, EN 61000-3-12, EN55022, FCC Part 15, CISPR 22 Class A |
| Safety | |
| Standards | EN 62368-1, UL 62368-1, IEC 62368-1 |
| Warranty | 2 years from date of purchase; extended terms by quote |
Capacity guidance: 1 shelf up to 33 kW · 2–3 shelves for mid-density AI racks · 4 shelves up to 132 kW.
AX5-33 — frequently asked questions
Can the AX5-33 run on DC input as well as AC?
Yes, and at full rating either way. The shelf accepts 346–480 VAC three-phase wye (4W + G) or 180–400 VDC at 240 VDC nominal. There is no derating on DC, and efficiency, hold-up time and the pulse envelope are the same on both. That means the same shelf works on a conventional AC service or downstream of facility DC distribution. 400 VDC is the ceiling; 800 VDC distribution requires the DX8-90 step-down.
How does this differ from the 800 VDC AX8 and DX8 platforms?
Conversion stages and where they sit. The AX5-33 takes facility power straight to 50 VDC at the rack in one stage, which is the simplest path and keeps the conversion local. The 800 VDC route uses the AX8-110 to convert facility AC to 800 VDC, then the DX8-90 to step down to 50 VDC at the rack. Choose the AX5-33 where a single stage and a simple rack power path matter more than facility-scale DC distribution.
What happens to a GPU pulse load?
It is absorbed rather than passed through. Each PSU5-55 carries 120 J of bulk capacitance, enough for 160% of rating on a 400 µs moving average, 136% for 50 ms and 100% for 1 s, all within regulation and without initiating battery discharge. If a pulse outlasts the stored energy, the PSU asserts Pulse_Mgmt_L to request load sharing from the battery shelf; if that is declined it raises its own input power limit rather than dropping the rail.
How much redundancy does the shelf give, and how does it scale?
One shelf gives 33 kW at N+0, 27.5 kW at N+1, or 16.5 kW at N+N. Four shelves in parallel reach 132 kW at N+0, which supports a 100 kW IT rack with redundancy. A Power Monitoring Controller on each shelf aggregates module data and coordinates operation across parallel power and battery shelves.
Is battery backup required?
No, it is optional. The 2 OU battery shelf holds up to six 5.5 kW BBU5-55 modules for 33 kW, delivering 5.5 kW for 90 seconds or more per module and matching the PSU pulse envelope. Battery discharge can be verified over Modbus without taking an outage, since AC_LOSS_L is toggleable.
What warranty applies?
2 years from date of purchase, with extended terms available by quote. The AX5-33 is preliminary, so confirm ratings and terms for a specific configuration before order.
Datasheets & references
Plan rack power infrastructure with confidence
Work with Xtreme Power to design and deploy rack-level power systems tailored to your application and density requirements. Prefer to connect directly? Contact our team at dcsales@xpcc.com or call (800) 582-4524.