Product Introduction
When power distribution in a CompactLogix system fails, the Allen-Bradley 1769-PA4 I/O Power Supply provides reliable backplane power. Part of the CompactLogix family, this 1769-PA4 unit delivers selectable AC input and dual DC outputs. It powers up to 16 I/O modules with a distance rating of 8 modules per side.
Technical Specifications Breakdown
The Allen-Bradley 1769-PA4 features a selectable input voltage range of 85...265V AC or 170...265V AC, switch-selectable to match your facility voltage. Its current capacity is 4.0 A at 5V DC and 2.0 A at 24V DC, ensuring sufficient power for up to 16 CompactLogix modules. Power consumption is 200 VA at 120V AC and 240 VA at 240V AC. The internal fuse (Littelfuse 02153.15MXP or Wickmann 19195-3.15A) protects against overcurrent. The unit dissipates 18 W at 60 °C and handles inrush current up to 25 A at 132V AC.
Installation & Setup Guidance
Mount the 1769-PA4 on DIN rail or panel using the provided latches. Use copper wire rated 90 °C: solid 22–14 AWG or stranded 22–16 AWG. Before energizing, set the voltage selector switch to the correct input range to prevent damage. Connect the bus connectors to adjacent modules. Ensure the power supply distance rating is not exceeded (maximum 8 modules on each side). The terminal block includes a finger-safe cover.
Troubleshooting & Common Issues
If the power supply fails to start, check the fuse and replace only with Littelfuse 02153.15MXP or Wickmann 19195-3.15A. Verify the input voltage selector is set correctly. A flashing LED indicates a fault; consult the manual for codes. Inrush current can trip breakers—use a slow-blow breaker if needed. Never exceed the distance rating; doing so can cause brownouts. The Allen-Bradley 1769-PA4 operates reliably in 0–60 °C environments with 5–95% non-condensing humidity and withstands 30 g shock.
Maintenance & Reliability
Periodically inspect the 1769-PA4 for dust buildup on the enclosure. Clean with dry compressed air. The fuse is replaceable; always use the specified types. Store the module between -40 and 85 °C. The unit's open-style enclosure requires proper ventilation. With proper handling, this power supply provides long service life in industrial control systems.