Allen-Bradley 1768-PA3 CompactLogix AC Power Supply Module

Product Overview

The Allen-Bradley 1768-PA3 serves as the primary power source for the 1768 CompactLogix system, providing essential DC power to the backplane. This module converts standard industrial AC or DC input voltages into the specific levels required by the controller and its associated modules. Because the 1768 series utilizes a high-performance architecture, this power supply is specifically keyed to support the L4x and L4xS controller families. It features an open-style design that allows for versatile mounting on either a DIN rail or a flat panel within an industrial enclosure.

Technical Capabilities and Performance

• Manufacturer: Allen-Bradley / Rockwell Automation
• Module Type: System Power Supply
• Catalog Number: 1768-PA3
• Input Voltage (AC): 85–265V AC (nominal 120/240V AC)
• Input Voltage (DC): 108–132V DC
• Frequency Range: 47–63 Hz
• Power Consumption: 120VA or 120W (Maximum)
• Backplane Output Current: Supports 1768 controllers and up to eight 1769 I/O modules
• Power Supply Efficiency: 75% typical at full load
• Enclosure Rating: Open-type (IP20)
• Operating Temperature: 0° to 60° C (32° to 140° F)
• Isolation Voltage: 250V (continuous), Reinforced Insulation Type

Operational Applications

Engineers implement the 1768-PA3 in automation cells that utilize the 1768-L43 or 1768-L45 motion controllers. This power supply is mandatory for configurations involving Sercos interface modules or high-speed Ethernet/IP modules that reside on the 1768 backplane. Since the unit supports a wide input voltage range, it performs reliably in global manufacturing environments where power standards fluctuate between 120V and 240V. Its ruggedized construction makes it suitable for heavy-duty process control and safety-integrated machinery.

Core Features

• The module provides high-capacity current to the backplane to drive both the processor and local I/O expansion banks.
• An integrated LED status indicator provides immediate visual feedback regarding power health and fault conditions.
• Internal overcurrent protection includes a non-replaceable fuse to safeguard the entire system from electrical surges.
• The 1768-PA3 supports the attachment of up to eight 1769 I/O modules, provided they stay within the power supply’s distance rating.
• Advanced isolation barriers protect the logic circuitry from line-side transients and industrial noise.
• Selective input jumpers or auto-ranging capabilities allow the supply to adapt to various field power sources without complex reconfiguration.