Product Overview

The Allen-Bradley 1756-PA72 is a high-efficiency AC power supply module designed specifically for the ControlLogix® chassis platform. This unit serves as the primary power source for the backplane, distributing multiple DC voltage levels to processors, I/O modules, and communication interfaces. Engineered for global versatility, it accepts a wide range of input voltages and features a robust 75-watt output capacity, making it suitable for high-density chassis configurations.

The 1756-PA72 is built to maintain system uptime in volatile industrial environments. It includes integrated overcurrent and surge protection to safeguard sensitive electronic components. Its chassis-mounted design ensures a secure physical connection and optimal thermal management within the ControlLogix assembly.

Technical Specifications

• Manufacturer: Allen-Bradley / Rockwell Automation

• Model Identification: 1756-PA72

• Module Function: Chassis Power Supply

• Input Voltage Range: 85–265V AC (Universal)

• Input Frequency: 47–63 Hz

• Maximum Real Power: 75 Watts

• Apparent Power: 100 VA

• Current Capacity (Output): 10A @ 5.1V DC; 4A @ 3.3V DC; 2.8A @ 24V DC; 1.5A @ 1.2V DC

• Operating Temperature: 0 to 60°C (32 to 140°F)

• Enclosure Rating: Open-style

• Dimensions: 11.0 x 14.3 x 13.8 cm

• Weight: 1.14 kg

Critical Performance Characteristics

• Holdup Time Capability: The module is designed with a specific holdup time (typically 5 cycles at 85V AC), allowing the controller to execute an orderly shutdown or transition to a safe state during brief power interruptions or brownout conditions.

• Visual Diagnostics: A front-panel green LED indicator provides real-time status of the power supply health, allowing technicians to verify voltage output at a glance.

• Isolation Architecture: Features reinforced insulation to protect the logic-side circuitry from field-side AC line disturbances, ensuring long-term hardware reliability.

• Compliance and Safety: This module meets international standards including UL, CSA, CE, and C-Tick, certifying its use in hazardous and standard industrial locations globally.

Installation and Maintenance

The 1756-PA72 mounts directly to the left side of any 1756 ControlLogix chassis. It features a user-accessible fuse for overcurrent protection, though the unit is designed to be largely maintenance-free under normal operating conditions. Its high current rating on the 5.1V rail makes it particularly effective for powering multiple high-performance Logix5000 processors within a single rack.