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Emerson / DC Power Systems (-48V)

HD4850-2 Equipment information & support

The Emerson HD4850-2 is an industrial carrier-grade switch-mode telecom rectifier module engineered to convert utility AC power into stable -48V DC (adjustable from -43V to -58V DC), delivering a rated output current of 50A and maximum rated power of 2900W. It is built to provide uninterrupted high-integrity DC power in demanding mission-critical telecom environments.

Equipment information

Brand
Emerson
Equipment model
HD4850-2
Equipment type
DC Power Systems (-48V)
Controller / software version
Confirm against the installed equipment
View full product specifications
Emerson HD4850-2 Genuine Telecom Hardware Shot 4

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

Rated Output Voltage
-48VDC (-42V ~ -58V)
AC Input Voltage
90V AC ~ 290V AC
Maximum Output Current
50A
Rated Output Power
2900W
Maximum Efficiency
≥ 93.0%
Operating Temperature Range
-40°C ~ +75°C

Alarms & troubleshooting

MAINS_FAIL / AC_POWER_LOSS (Utility Grid Failure / Total AC Ingress Loss)
Cabinet controller red ALARM LED solid with acoustic buzzer; system seamlessly transitions to battery discharge.
Grid utility failure, upstream transformer trip, automatic transfer switch (ATS) fault, or tripped main breaker.
1. Verify battery discharge current and remaining backup runtime on controller; 2. Start backup diesel generator (DG) and verify ATS transfer; 3. Measure incoming 3-phase line voltage and frequency stability; 4. Upon grid restoration, verify rectifiers soft-start and engage battery recharge.
LLVD_TRIP / LOAD_SHEDDING (Load Low Voltage Disconnect Tripped)
Controller LCD triggers LLVD alarm; LLVD contactor mechanically opens; secondary load branches de-energized.
Prolonged mains outage discharging batteries to protection threshold (typically 44.0VDC). System automatically sheds secondary loads to preserve core communications.
1. Confirm critical core branches (BLVD circuit) remain energized and protected; 2. Dispatch emergency mobile power generation cart to site; 3. Upon grid recovery, monitor DC bus voltage ramp above re-engagement threshold (48.0VDC); 4. Verify LLVD contactor re-closes and secondary equipment boots normally.
SPD_FAIL / SURGE_ARRESTOR (Surge Protective Device Degradation / Tripped)
Controller registers SPD alarm; SPD module inspection window turns from Green to Red; alarm dry contact closes.
Site subjected to lightning surge strike or sustained overvoltage, causing MOV thermal breakdown and disconnect.
1. Inspect SPD indicator flags (red flag confirms blown cartridge); 2. Check SPD dedicated backup fuse or circuit breaker; 3. Open SPD isolation switch, extract damaged plug-in cartridge; 4. Replace with genuine replacement cartridge matching rating (20kA/40kA); 5. Close circuit, verify green status flag and alarm self-clearing.

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.

Contact Account Manager for Full Manual

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