Product Overview

The Allen-Bradley 1746-P1 is a high-reliability, chassis-mounted power supply engineered specifically for the SLC 500 programmable logic controller platform. Serving as the electrical foundation for the system, this module is responsible for rectifying AC input power into the stabilized DC voltages required by the SLC backplane. It occupies the dedicated power supply slot located on the far left of any 1746 chassis, providing the necessary energy to drive the CPU, I/O modules, and any connected specialty cards.

Designed for global industrial compatibility, the 1746-P1 features a dual-range input architecture. It can be configured to operate on 120V AC or 240V AC nominal utility power via a manual jumper selection. Beyond powering the internal backplane, the module also provides an auxiliary 24V DC user-power output, which can be utilized to drive field-side devices such as sensors or small relays, reducing the need for external power hardware in compact control cabinets.

Technical Performance and System Protection

The 1746-P1 is built to ensure maximum uptime for critical control processes. It incorporates a deterministic "hold-up" time, a feature that allows the SLC 500 processor to maintain operation through momentary power dips or brownouts. This prevents unnecessary system resets and process interruptions. Furthermore, the module is equipped with integrated overcurrent and short-circuit protection, shielding the expensive logic components in the rack from field-side electrical faults.

Thermal management is handled through a ruggedized housing designed for passive convection cooling, supporting continuous operation in ambient temperatures up to 60°C. This industrial-grade rating makes the 1746-P1 suitable for high-density control panels where heat accumulation is a common concern. Its robust construction and proven track record make it a standard choice for both original system builds and critical legacy maintenance.

Technical Specifications

• Manufacturer: Allen-Bradley (Rockwell Automation)

• Model Number: 1746-P1

• Module Type: SLC 500 Rack Mount Power Supply

• Input Voltage (AC): 85–132V AC or 170–265V AC (Jumper selectable)

• Input Frequency: 47–63 Hz

• Backplane Current (5V DC): 2.0 Amps

• Backplane Current (24V DC): 0.46 Amps

• User Power (24V DC): 0.20 Amps (Auxiliary output)

• Max Real Power: 13.5 Watts

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

• Mounting Location: Leftmost slot of 1746 Chassis

• Weight: 0.9 kg (approx. 2.0 lbs)

• Dimensions: 3.5 x 13.0 x 14.5 cm

Core Operational Characteristics

• Dual-Range AC Input: Supports both domestic and international power standards through a simple jumper configuration.

• Integrated Protection: Built-in fusing and electronic protection safeguard the processor and I/O modules from input surges.

• Auxiliary DC Source: Includes a 24V DC terminal for powering external instrumentation directly from the rack.

• High Reliability: Engineered for long-term service in demanding environments, minimizing the total cost of ownership for SLC 500 systems.