Allen-Bradley 1756-PA72 ControlLogix Chassis Power Supply Module

Overview

The Allen-Bradley 1756-PA72 is a backplane power supply module for the 1756 ControlLogix chassis, converting universal 120/240V AC line input (85–265V AC range) into the regulated 5.1V DC backplane power that every module in a ControlLogix rack – controller, I/O, and communication cards – draws to operate. Every ControlLogix chassis requires exactly one power supply module occupying its dedicated slot, and the 1756-PA72 is the standard AC-input entry point into Rockwell Automation’s 1756 power supply family, which also includes higher-current, DC-input, and redundant variants for different site power arrangements.

In Oman and the GCC, Seven Star LLC supplies the Allen-Bradley 1756-PA72 ControlLogix chassis power supply module across Oman and the wider GCC, with locally available technical support for both new panel builds and spare-parts replacement on installed ControlLogix systems.

Operating Principle

The Allen-Bradley 1756-PA72 rectifies and regulates its AC input into the 5.1V DC rail that the ControlLogix backplane distributes to every module slot, with the power supply’s rated output current setting a hard ceiling on how many modules, and which controller, a given chassis can support – the 5.1V rail is almost always the constraint system designers must check first when sizing a rack. Internally, the supply continuously monitors output voltage and current, providing status indication and, on some variants, a dry contact or diagnostic signal usable for remote power-health monitoring.

Because every module in the chassis draws its logic power from this single 5.1V backplane rail rather than from individual per-module supplies, the 1756-PA72’s current rating directly determines the maximum practical module count and controller size that a chassis can host; exceeding the rated capacity of the 1756-PA72 or its siblings is one of the most common design errors in new ControlLogix panel layouts, which is why Rockwell publishes chassis-by-chassis power budget tables for each supply in the family.

Engineering Design of the Allen-Bradley 1756-PA72

The Allen-Bradley 1756-PA72 mounts directly into the dedicated power supply slot at the left end of any standard 1756 ControlLogix chassis, with no backplane connector wiring required beyond the chassis itself. The module accepts a universal 85–265V AC input via a removable terminal block, eliminating the need for a separate step-down transformer in most regional power environments, and includes LED status indication for input power and output health directly on the module face.

The 1756-PA72 shares its physical mounting method, terminal block wiring approach, and diagnostic LED layout with every other member of the 1756 power supply family (1756-PA75, 1756-PB72, 1756-PB75, 1756-PC75, 1756-PH75), so a site standardizing on ControlLogix hardware can stock a single spares and documentation set covering AC and DC input variants at two current ratings, plus redundant PA75R/PB75R versions for chassis requiring dual-supply failover via a 1756-PSCA2 adapter.

Key Features

The Allen-Bradley 1756-PA72 provides reliable, standardized backplane power for ControlLogix chassis of any size:

• Universal 85–265V AC input accepts both 120V and 240V regional supply without a separate transformer or input selector.
• Delivers 5A at 5.1V DC backplane power, sized for small-to-medium ControlLogix chassis and controller/I/O combinations.
• Single dedicated power-supply slot per chassis, with no backplane jumpers or configuration required at installation.
• Removable terminal block wiring simplifies field replacement without disturbing adjacent panel wiring.
• Front-panel LED status indication shows input power presence and output health at a glance.
• Shares mounting method and diagnostics layout with the entire 1756 power supply family for consistent spares stocking.
• Higher-current (1756-PA75) and DC-input (1756-PB72/PB75/PC75/PH75) siblings share the same footprint for easy re-specification.
• Redundant PA75R/PB75R variants are available via the 1756-PSCA2 adapter for chassis requiring dual-supply failover.

Industrial Applications

The Allen-Bradley 1756-PA72 is the standard backplane power supply specified for small-to-medium ControlLogix panels across Oman’s process and manufacturing base, including district cooling plant control rooms, water and wastewater pumping stations, and machine-level control panels in cement and materials-handling facilities where a compact chassis with a single controller and a handful of I/O modules is sufficient. Its universal AC input also makes it a straightforward replacement part for maintenance teams standardizing spares across multiple ControlLogix panels on one site.

In Oman and the GCC, Seven Star LLC supplies the 1756-PA72 to systems integrators, panel builders, and plant maintenance teams across the Sohar and Salalah economic zones and the wider GCC, supporting both new-build ControlLogix panels and the ongoing spare-parts continuity of installed automation systems.

Technical Specifications

The Allen-Bradley 1756-PA72 key specifications, alongside its sibling models in the same power supply family, are listed below for reference:

Sibling power supplies in the 1756 family, sharing the same chassis mounting method:

Request a Quote for Allen-Bradley 1756-PA72

Seven Star LLC invites systems integrators, panel builders, and plant maintenance teams across Oman and the GCC to submit a formal RFQ for the Allen-Bradley 1756-PA72 ControlLogix chassis power supply module. In Oman and the GCC, Seven Star LLC confirms availability and lead time at quotation, provides the full 1756-PA72 technical datasheet on request, and connects customers directly with the automation division for chassis power-budget sizing and spare-parts support.

Browse the full Allen-Bradley range or see more PLC & I/O Cards products supplied by Seven Star LLC in Oman and the GCC.