Configured for DC-input to DC-output conversion in the ABB Advant Master S100 rack, the ABB DSSR122 48990001-NK (DSSR122 Rack Power Supply) provides direct 5 VDC 40 A regulated bus power to backplane-mounted controller and I/O cards.

Catalog String and Part Number Mapping

DSSR122 is the base module type. 48990001-NK is the ABB spare/product ID (alternate exchange ID EXC48990001-NK). The "-NK" suffix is a shipment batch code, not a hardware revision; DSSR122 48990001-NK and DSSR122 48990001-NK (EXC) share the same electrical and mechanical envelope. Do not confuse with DSSR132 (24 VDC output variant) or DSQC AC-DC robot supplies.

Hardware Specifications

Backplane Bus Power and S100 Rack Integration

The module seats in the dedicated power slot of DSRF182-class S100 I/O racks and feeds the 5 VDC logic rail for Advant OCS AC410/AC450, MasterPiece 100/200 and S100 digital/analog cards. It does not source 24 VDC field power; that rail is supplied separately by the station DC distribution. N+1 parallel redundancy is supported by installing multiple DSSR122 units in separate rack power slots under diode OR-ing; no external tie module is required. Backplane inrush at 24 VDC input is bounded by the internal 20 A fuse; replacement fuse class is slow-blow 20 A 5672827-20 only. MB300 bus communication velocity is unaffected because the supply drives static logic rails, not the serial transceiver termination directly.

Ordering Info

• 1 x DSSR122 power supply body 48990001-NK
• 1 x internal 20 A spare fuse 5672827-20 pre-installed
• 2 x rack ejection levers / DIN clip adapters
• 1 x printed warning label sheet (RoHS exemption note)
• No front connector, no backplane ribbon, no 24 VDC input cabling included

Rack Fitting and DC Bus Wiring

• Verify incoming DC bus is 18-30 VDC before insertion; 48 VDC INFI-90 variant is a different batch, do not mix.
• Tighten 24 VDC input lug to 1.2 Nm; use 6 mm2 minimum copper for 40 A output bus bar tie.
• Mount in S100 slot with both ejector levers fully seated; partial insertion trips Power OK LED off.
• Separate 24 VDC input runs from 5 VDC output bus by 50 mm minimum to suppress switching noise coupling.
• Never bridge 5 VDC output to 24 VDC field rail; DSSR122 has no 24 VDC output stage.

Frequently Asked Questions

What input voltage range does DSSR122 48990001-NK accept?

18-30 VDC with 24 VDC nominal. Below 18 VDC the output drops out of regulation; above 30 VDC the input overvoltage clamp latches and requires power cycle. 48 VDC batches exist under INFI-90 label only, not under 48990001-NK.

Can DSSR122 be hot-swapped in a live S100 rack?

Yes, the S100 power slot supports hot extraction/insertion. Before pull, confirm N+1 redundancy active so 5 VDC rail stays within +/-2 %; single-unit swap on a non-redundant rack forces controller reboot.

What fuse replaces the internal 20 A device?

ABB spare 5672827-20, slow-blow 20 A, ceramic body. Do not substitute with fast-acting automotive blade fuses; inrush at insertion will false-blow and disable the module.

Does DSSR122 supply 24 VDC to field instruments?

No. Output is single-rail 5 VDC 40 A for rack logic only. S100 24 VDC field power comes from external DC distribution, often a separate DSSR132 or station PSU. Mixing rails on same bus bar causes backfeed damage.

Is 48990001-NK firmware or config flashable?

No. DSSR122 is an analog switching regulator with no microprocessor, no firmware, no configuration EEPROM. Status is hardware-derived from sense amps and comparator logic only.

What indicates output overload on the front face?

Power OK green extinguishes and Fault LED amber lights when output current exceeds 40 A or when overtemperature threshold (~70 deg C heatsink) is reached. Auto-recovery occurs 2 s after fault clears.

Can two DSSR122 units share one 5 VDC backplane without diode OR-ing?

Not recommended. Direct parallel tie without OR-ing diodes causes current imbalance and single-unit dominance. S100 redundant slots already provide OR-ing; external tie frames need 40 A Schottky diodes per unit.

What is the MTBF and cooling requirement?

Typical MTBF ~300,000 h at 40 deg C ambient with natural convection. Forced fan cooling is not required but cabinet airflow must exceed 0.5 m/s past heatsink fins; sealed enclosures without ventilation trip thermal shutdown.