ABB 086318-002 | Redundant PSU for AC 800M | End-of-Life Risk Analysis in Process Automation
ABB 086318-002 | Redundant PSU for AC 800M | End-of-Life Risk Analysis in Process Automation - Image 2
ABB 086318-002 | Redundant PSU for AC 800M | End-of-Life Risk Analysis in Process Automation - Image 3

ABB 086318-002 | Redundant PSU for AC 800M | End-of-Life Risk Analysis in Process Automation

  • Models: 086318-0002 (primary) and 086318-501 (redundant/backup variant)
  • Brand: ABB
  • Core Function: 24 VDC power supply modules for the AC 800M programmable automation controller (PAC) system
  • Lifecycle Status: Discontinued (Obsolete)
  • Procurement Risk: High – no longer manufactured; limited to secondary market with concerns over capacitor aging, output stability, and authenticity
  • Critical Role: Provides primary or redundant power to AC 800M CPU and I/O modules; failure can cause complete controller shutdown or loss of redundancy

 

Category: SKU: 086318-002 086318-501

Description

Technical Specifications (For Spare Verification)

  • Product Models: 086318-002 (standard), 086318-501 (redundancy-enabled version)
  • Manufacturer: ABB
  • System Family: AC 800M (used in 800xA, Power Generation, and Industrial Process Control)
  • Output Voltage: +24 VDC nominal
  • Output Current: Typically 10 A continuous (shared across backplane loads)
  • Input Voltage: 85–264 VAC, 47–63 Hz (universal input)
  • Redundancy Support: 086318-501 includes diode-oring circuitry for parallel operation with another PSU
  • Form Factor: DIN rail-mounted, occupies one slot in AC 800M rack
  • Diagnostic Features: LED indicators for “OK”, “Fault”, and “Redundancy Active” (on -501 variant)
  • Efficiency & Cooling: Convection-cooled; no fan required
  • Safety Certifications: CE, UL, CSA (original units only; not guaranteed on used stock)

086318-002 086318-501

086318-002 086318-501

 

System Role and Downtime Impact

The ABB 086318 series power supplies are foundational to the stable operation of AC 800M control racks. They convert mains AC into regulated 24 VDC for the entire backplane, powering CPUs, communication modules, and I/O cards. In non-redundant configurations, a single 086318-002 failure results in immediate loss of controller function—halting all logic execution and I/O updates. In redundant setups using the 086318-501, a primary supply failure should be seamlessly covered by the backup unit; however, if both units are aged or from degraded inventory, cascading failure is possible. In continuous processes such as steam turbine control, boiler management, or chemical batch systems, such a power fault typically triggers a full process trip. Recovery requires physical replacement and system reboot, with potential for hours of downtime depending on safety interlocks.

 

Reliability Analysis and Common Failure Modes

Despite robust industrial design, these power supplies are vulnerable to several time-dependent failure mechanisms:

  • Electrolytic capacitor drying or bulging due to prolonged thermal stress, leading to output ripple, voltage droop, or complete shutdown.
  • Degradation of switching transistors or rectifier diodes after 15+ years of operation, especially in high-ambient environments like electrical rooms without climate control.
  • Corrosion on terminal blocks or backplane connectors causing intermittent power delivery—often misdiagnosed as a CPU fault.

A key weakness in early units is the lack of active power factor correction (PFC), making them more sensitive to input voltage sags or harmonics from nearby VFDs. Additionally, the redundancy diodes in the 086318-501 generate heat during normal operation, accelerating component aging if ventilation is inadequate.

Preventive maintenance recommendations include:

  • Annual measurement of output voltage under load during plant outages.
  • Visual inspection for swollen capacitors or discoloration near power components.
  • Cleaning of ventilation paths and ensuring minimum 50 mm clearance around each PSU.
  • Avoiding mixing old and new (or different revision) PSUs in redundant pairs to prevent current imbalance.

086318-002 086318-501

086318-002 086318-501

 

Lifecycle Status and Migration Strategy

ABB has formally discontinued the 086318 series as part of the evolution toward newer AC 800M hardware generations (e.g., PM866A with updated power architecture). Official support, including repairs and replacements, is no longer available. The remaining global inventory consists of used or New Old Stock (NOS) units, many of which have already exceeded their designed service life. Continuing to operate with these modules carries significant risk: latent capacitor failures can occur without warning, and untested spares may fail immediately upon installation.

Short-term mitigation strategies include:

  • Securing at least one fully tested spare per critical rack, verified for stable output under full load.
  • Engaging specialized vendors for board-level refurbishment, including full capacitor replacement and thermal imaging validation.
  • Implementing external UPS or line conditioning to reduce input stress on aging supplies.

For long-term sustainability, ABB recommends upgrading to current-generation AC 800M power supplies such as the 086319-001 or 086320-001 series, which feature:

  • Improved efficiency and thermal performance
  • Enhanced diagnostics via the 800xA asset portal
  • Full compatibility with modern PM86x CPUs

Migration typically requires only mechanical and electrical replacement—no logic changes—but must be performed during a planned outage. Facilities with multiple legacy racks should prioritize power supplies in safety-critical or high-availability applications for early refresh. Until full migration, proactive health monitoring and disciplined spares management remain essential to avoid unplanned controller outages.

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