Allen-Bradley 1746-P2 SLC 500 Power Supply

Overview

The Allen-Bradley 1746-P2 is the AC input power supply for the SLC 500 programmable controller family, providing the DC power that the chassis backplane and SLC 500 modules need to operate. Accepting line voltages of 85-132 V AC or 170-265 V AC at 47-63 Hz with a typical line power of 180 VA, the 1746-P2 delivers 5 A at 5 V DC and 0.96 A at 24 V DC to the chassis, with additional 24 V DC user power for external devices.

Seven Star LLC supplies the Allen-Bradley 1746-P2 power supply for SLC 500 control systems across the Sultanate of Oman and the GCC. Water treatment, power, oil and gas, and industrial plants continue to operate SLC 500 systems, and our team provides genuine Allen-Bradley spare parts with regional delivery to Muscat, Sohar, Salalah, and beyond.

Operating Principle

The SLC 500 chassis backplane carries both data and power to the processor, I/O modules, and specialty modules installed in the chassis. The 1746-P2 mounts in the chassis and converts the AC mains supply into the regulated 5 V DC and 24 V DC rails that the backplane distributes to all modules. Correct power supply selection is essential: each module consumes backplane current, and the power supply must be sized to cover the total current demand of the installed configuration.

The 5 V DC rail powers the logic and I/O circuitry of the modules, while the 24 V DC rail serves modules with internal 24 V requirements. The power supply also provides 24 V DC user power, which can be used to power small external devices such as sensors and indicators without a separate supply.

Supply behaviour during disturbances matters as much as steady-state capacity. Rockwell specifies a CPU hold-up time of 20 ms at full load and up to 3000 ms at no load, so brief mains dips do not force a processor restart, while 1800 V AC RMS isolation for one second between the input terminals and the backplane keeps line-side transients off the logic rails. The 24 V DC user-power output is rated 200 mA over an 18-30 V DC range, and Rockwell specifies a maximum 15 A time-delay overcurrent device in the ungrounded supply conductors ahead of the unit.

Engineering Design of the Allen-Bradley 1746-P2

The 1746-P2 is built to the SLC 500 chassis standard: it slides into the dedicated power supply slot and connects directly to the backplane, so no separate wiring is needed for module power. It accepts the wide AC input range of 85-132 V AC or 170-265 V AC at 47-63 Hz, making it suitable for the 220-240 V AC mains common in the GCC. The dual input range is not automatic: an input voltage jumper on the supply must be set to the 200/240 V position before power is applied.

With a typical line power of 180 VA and a maximum inrush current of 20 A, the power supply is matched to the SLC 500 chassis range. The unit uses the standard 1746-F2 fuse, and its internal current ratings — 5 A at 5 V DC and 0.96 A at 24 V DC — define the load capacity for the chassis configuration.

Installation and Wiring

The power supply occupies the dedicated slot at the left-hand end of the SLC 500 modular chassis — 1746-A4, 1746-A7, 1746-A10, or 1746-A13 — where its circuit board aligns with the chassis card guide and is secured by two Phillips head screws to a maximum torque of 1.2 Nm (11 lb-in). Field wiring lands on a five-terminal block carrying PWR OUT +24V DC, PWR OUT COM, the 120/240 V AC line, V AC NEUT, and chassis ground, and Rockwell specifies a terminal screw torque of 0.8 Nm (7 lb-in) for the Allen-Bradley 1746-P2.

The chassis ground screw should be bonded to the nearest ground bus using #14 AWG 75 °C copper conductor kept as short as practical, in line with the Industrial Automation Wiring and Grounding Guidelines. Ambient operating temperature is specified as 0 to 60 °C, with current capacity derated by five percent above 55 °C — a figure worth observing in unventilated GCC panel rooms, where internal cabinet temperature routinely runs well above outdoor shade temperature. Where the unit is marked accordingly it carries UL and C-UL listing as industrial control equipment for Class I, Division 2, Groups A, B, C and D hazardous locations, together with CE and C-Tick marking.

Key Features

The Allen-Bradley 1746-P2 is specified for SLC 500 chassis powering. Its defining characteristics are:

• Genuine Allen-Bradley SLC 500 chassis power supply.
• Input range 85-132 V AC or 170-265 V AC at 47-63 Hz.
• Typical line power of 180 VA with 20 A maximum inrush.
• Delivers 5 A at 5 V DC and 0.96 A at 24 V DC to the backplane.
• 24 V DC user power output for small external devices.
• Uses the standard 1746-F2 fuse for protection (equivalent 250 V 3 A, Bussmann AGC 3).
• Input voltage jumper selectable for 100/120 V AC or 200/240 V AC operation.
• CPU hold-up time of 20 ms at full load, riding through short mains dips.
• 1800 V AC RMS isolation for one second between input terminals and backplane.
• Direct backplane connection in the SLC 500 chassis power slot.
• Supplied by Seven Star LLC for control system spares across Oman and the GCC.

Industrial Applications

The 1746-P2 serves the installed base of SLC 500 control systems in the region: water and wastewater pumping stations, power and desalination auxiliary systems, oil and gas process skids, and general machine control. For plants that continue to operate SLC 500 hardware, a genuine spare power supply is essential inventory, because the power supply is the single point that feeds every module in the chassis.

Seven Star LLC supports maintenance teams across the Sultanate of Oman and the GCC with the Allen-Bradley 1746-P2 and the complete SLC 500 spare parts range. We provide Allen-Bradley modules on request and power supply selection guidance, so that control system spares from Muscat to Salalah are sourced from a documented supplier.

Technical Specifications

The following table summarises the key parameters of the Allen-Bradley 1746-P2 power supply:

Lifecycle Status and Series Differences

Rockwell Automation lists the 1746-P2 as a rack-mount SLC power supply (120/240 V AC, 5 A at 5 V DC) with a lifecycle status of Discontinued as of 30 September 2024 and no planned replacement. Repair services and documentation remain available through Rockwell support channels. The SLC 500 platform itself is generally described as Active Mature, with CompactLogix and Compact 5000 systems offered for new designs and migration planning.

The 1746-IN004 installation instructions note that behaviour under a 24 V DC user power overcurrent depends on the series. On series A and B units the power supply shuts down and the CPU faults, requiring the user program to be reloaded. On series C units only the 24 V DC user output shuts down and the CPU continues running. Rockwell advises monitoring the 24 V DC user output with a 24 V DC input channel to avoid unexpected operation.

Request a Quote for Allen-Bradley 1746-P2 SLC 500 Power Supply

Request a formal quotation for the Allen-Bradley 1746-P2 power supply through the Seven Star LLC RFQ portal, and our team will confirm availability, lead time and delivery to Oman or any GCC destination. As a trusted supplier of Allen-Bradley control system spares in the region, we also provide power budget guidance and cross-reference support for SLC 500 chassis. Contact Seven Star LLC today.

Power Budget and Spares Planning

Calculate the backplane power budget of the SLC 500 chassis by summing the 5 V DC and 24 V DC current consumption of the processor, I/O, and specialty modules, and confirm the total is within the 1746-P2 ratings of 5 A at 5 V DC and 0.96 A at 24 V DC. Use the specified 1746-F2 fuse and the 24 V DC user power output for small external devices. Seven Star LLC supports SLC 500 users in Oman and the GCC with genuine Allen-Bradley spares and power budget guidance.

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Also available: Allen-Bradley 1747-M13 Memory Module for SLC 500