Vertiv / DC Power Systems (-48V)

R48-3500e3 Equipment information & support

The Vertiv R48-3500E3 is a high-density digital AC/DC rectifier converting single-phase AC to precision -48V DC, optimized for heavy-load communication systems with active PFC and autonomous load sharing.

Equipment information

Brand: Vertiv
Equipment model: R48-3500e3
Equipment type: DC Power Systems (-48V)
Controller / software version: Confirm against the installed equipment

View full product specifications

Information below comes from the current product catalogue. Confirm the controller, software version and configuration of the installed equipment separately.

Output Voltage Range: -48VDC (-42V ~ -58V) VDC
AC Input Phase Voltage Range: 85 ~ 300 VAC
Output Power Factor PF: ≥0.99
Wide Operating Temperature Range: -40°C ~ +75°C
Cooling Architecture: Built-in fan-forced air cooling (with temperature-controlled speed regulation)
DC Output Voltage: -48VDC (-42V ~ -58V) V DC

Alarms & troubleshooting

AC_IN_FAIL (AC Input Abnormal / Mains Loss)

Green Power LED Off, Yellow Protection LED Solid

AC mains input voltage <85Vac undervoltage cutoff, >300Vac overvoltage protection, or upstream AC circuit breaker tripped

1. Measure true RMS phase-to-neutral voltage at the module backplane input terminals. 2. Verify the rectifier circuit breaker on the AC Distribution Unit (ACDU) is closed and not tripped. 3. If AC voltage is verified within normal operating window (85-300Vac), reseat module to rule out connector pin contact failure or swap module.

DC_OVP (DC Output Overvoltage Lockout / HVSD)

Red Alarm LED Solid, Green Power LED Off

Internal voltage feedback loop failure or current-share anomaly causing output to exceed hardware overvoltage shutdown threshold (59.5V ±0.5Vdc), triggering latching lockout

1. Unseat the faulted rectifier module for at least 3 minutes to discharge internal bulk capacitors and reset hardware latching state. 2. Verify the system overvoltage threshold in the system controller (NCU/M830B) has not been incorrectly configured. 3. Reseat the module individually into an empty slot. If Red LED latches immediately upon energization, replace the defective rectifier.

OTP_ALARM (Over-Temperature Protection / Thermal Shutdown)

Yellow Protection LED Blinking (Derating) or Solid; Red Alarm LED Solid if fully shut down

Ambient temperature exceeding +65°C, clogged front ventilation grilles/dust filters, or internal heatsink NTC sensor exceeding +105°C limit

1. Check air conditioning operation and verify cold-aisle intake temperature is within spec (<+45°C). 2. Clean dust and debris accumulation from front intake bezel and perforated subrack panels using dry compressed air. 3. Verify internal cooling fan is spinning freely; once internal heatsink temperature drops below hysteresis threshold, rectifier automatically recovers.

FAN_FAIL (Fan Blocked / Tachometer Fault)

Yellow Protection LED Blinking (0.5Hz); Red Alarm LED Solid if module locks out

Cooling fan bearing mechanical seizure, foreign object jamming impeller blades, or internal Hall-effect tachometer failure

1. Visually inspect the fan assembly at the front/rear for cable snagging or physical foreign object obstruction. 2. Gently spin blades using an insulated probe to verify bearing turns smoothly without mechanical resistance. 3. If fan spins freely but fails to spin under load or tach alarm persists, replace the field-replaceable 48V DC cooling fan assembly.

CAN_COMM_FAIL (CAN Bus Communication Lost / Current Share Imbalance)

Yellow Protection LED Blinking (0.5Hz), Green Power LED Solid

Bent or oxidized CAN bus pins on the backplane connector, missing 120-ohm termination resistor, or controller (NCU) transceiver fault forcing module into autonomous fallback mode

1. Check the controller (NCU) display to verify whether communication is lost with a single module or all rack rectifiers. 2. If isolated to one module, withdraw the unit and inspect CAN-H/CAN-L pins on the rear blind-mate connector for bend or recession; clean pins and re-insert firmly. 3. If entire subrack is offline, measure resistance between CAN_H and CAN_L lines with power off (nominal should read ~60 ohms for dual parallel 120-ohm terminations).

Access Complete Maintenance & Full Alarm Troubleshooting Manual

This page lists high-frequency critical alarm codes commonly encountered in field maintenance. Comprehensive manufacturer troubleshooting matrices, board-level repair guides, detailed electrical schematics, and firmware commissioning manuals are delivered alongside equipment upon formal project procurement, accompanied by dedicated FAE technical support.

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