ABB DSSA165 Power Supply Unit

Configured for regulated auxiliary DC power distribution in ABB automation networks, the ABB DSSA165 (DSSA-165 Power Supply Unit) provides direct physical/electrical execution. Cataloged under order code 48990001-LY, this cabinet-mounted industrial power assembly converts AC line power into a stabilized 24 VDC output rating up to 25 A. The module establishes stable power rails for rack-mounted process controllers, local I/O clusters, and field instrument loops, isolating internal control bus electronics from line-side voltage fluctuations and transient noise spikes.

Hardware Specifications

Backplane Bus Communication Velocity & I/O Density Scaling

The ABB DSSA165 power architecture integrates directly into process control system racks to deliver deterministic power distribution across internal system buses. High-velocity system backplanes demand consistent voltage rails without high-frequency ripple to prevent frame corruption during high-density I/O polling cycles. By maintaining tight terminal regulation under full continuous load, the unit limits backplane noise levels and ensures deterministic bus communication speeds are preserved across adjacent processing cards and interface adapters. Integrated overload detection circuit pathways restrict backplane voltage drops during field loop switching events, maintaining system clock synchronicity and firmware flash compatibility during online operational updates.

Frequently Asked Questions

Q: What are the primary ventilation and cooling requirements for operating the DSSA165 at maximum current output?

A: The unit utilizes natural convection or forced-air cabinet cooling depending on enclosure density. Maintain a minimum vertical clearance of 100 mm above and below the power assembly frame to prevent thermal throttling when sourcing a full 25 A output load at 55 deg C ambient operating temperatures.

Q: Does the DSSA165 support parallel redundancy configurations for critical power rails?

A: Parallel operation for redundancy (N+1 configuration) requires external decoupling diodes or external power distribution modules to prevent reverse current flow between power units if one supply rail experiences a primary side failure.

Q: How does input voltage noise affect the 24 VDC output rail performance?

A: Internal LC filtering stages attenuate high-frequency line noise and AC mains harmonics at 50/60 Hz input frequencies, keeping DC output ripple within standard noise tolerance thresholds required for sensitive control logic and analog input loops.

Field Installation Guidelines

• Mount the assembly securely to cabinet structural framing or dedicated mounting plates using specified metric hardware, ensuring proper torque limits to support the heavy assembly frame.
• Ensure PE (Protective Earth) earth ground stud connections are established with low-impedance copper conductors prior to energizing primary AC input terminals.
• Maintain clear separation between primary AC input cabling and low-voltage 24 VDC field output lines in panel wireways to prevent inductive noise coupling.
• Verify input terminal supply voltage matching (115 VAC or 230 VAC line setting) prior to applying mains power.
• Tighten heavy-gauge 24 VDC output terminal lug connections to nominal manufacturer torque specs to minimize contact resistance under high-current 25 A continuous loads.