Allen-Bradley 1746-P3 SLC 500 Power Supply Module

Product Overview

Industrial control systems require reliable power to maintain uptime and protect downstream modules. The Allen-Bradley 1746-P3 is a 24VDC power supply designed for the SLC 500 platform. It mounts on the left side of a 1746 chassis and converts an input voltage range of 19.2-28.8 VDC into regulated backplane power. This module delivers 3.6 A at 5 VDC and 0.87 A at 24 VDC, ensuring stable operation for connected I/O and processor modules. Its compact footprint and robust certification make it a trusted choice for demanding environments.

Technical Specifications Breakdown

Key parameters for the 1746-P3 are listed below for quick reference:

Industry Applications

Discrete Manufacturing Lines – In automotive or packaging facilities, the 1746-P3 powers SLC 500 racks controlling conveyors and robotic cells. Its 5 ms hold‑up time at full load prevents processor resets during brief voltage sags, reducing unplanned downtime.

Process Control Skids – For chemical or water treatment systems, the module’s UL listing for Class I, Division 2 hazardous locations (Groups A, B, C, D) allows installation in areas where flammable gases or vapors may occasionally be present.

Material Handling Systems – Warehouses and distribution centers rely on the SLC 500 platform for sortation and storage. The 1746-P3 provides stable 5VDC and 24VDC backplane power, ensuring consistent communication between processor and I/O modules.

Installation & Setup Guidance

Mount the 1746-P3 on the left‑most position of a 1746 chassis. It does not occupy a slot. Use a 1/8 inch flat head or 1/4 inch Phillips screwdriver for installation. Keep the module in static‑shield packaging until ready to install. Avoid touching connector pins or circuit components to prevent electrostatic discharge damage. Connect the 24VDC input supply (19.2-28.8 VDC range) to the designated terminals. The recommended fuse is the Allen‑Bradley 1746-F3 or equivalent (BUSSMAN AGC 5 or Nagasawa ULCS-61ML-5). Ensure the ambient temperature stays between 0 and 60 °C; derate current capacity by 5% above 55 °C.

Maintenance & Reliability

Inspect the module periodically for dust accumulation and verify that the ambient temperature remains within the 0…60 °C range. The power supply includes a replaceable fuse; if the fuse opens, replace it only with the recommended 1746-F3 or equivalent. No isolation exists between backplane and input terminals, but dielectric withstand between chassis ground and input is 600V AC RMS for 1 second. The module is designed for Pollution Degree 2 environments and Category II installations. Altitude derating is not required up to 2000 meters.

Compatibility & Integration

The 1746-P3 is part of the Allen‑Bradley SLC 500 series and is compatible with all 1746 chassis and SLC 500 modules. It provides backplane power at 5VDC (3.6 A) and 24VDC (0.87 A). The module is certified by Underwriter’s Laboratories (UL) and C‑UL as Industrial Control Equipment for Class I, Division 2 hazardous locations. It also meets other standardization bodies’ requirements.

Selection Guide & Purchasing Advice

When selecting a replacement or spare power supply for your SLC 500 system, verify that the input voltage matches your facility’s DC supply (19.2-28.8 VDC). If your system demands higher current, consider other SLC 500 power supply options. AutoDCSTech stocks genuine Allen‑Bradley 1746-P3 modules. Contact our team to confirm lifecycle status and availability before ordering.

Troubleshooting & Common Issues

If the SLC 500 rack does not power up, first check the input voltage at the terminals (should be between 19.2 and 28.8 VDC). Verify that the fuse (1746-F3 or equivalent) is intact. If the fuse is blown, replace it and investigate the cause—often a shorted module on the backplane. If the power supply operates but modules fail intermittently, measure the backplane voltage at 5VDC and 24VDC. Ensure the total current draw does not exceed 3.6 A at 5VDC or 0.87 A at 24VDC. Overheating can occur if ambient temperature exceeds 60 °C; improve ventilation or relocate the chassis.