Technical Specifications
| Parameter Name | Parameter Value |
|---|---|
| Product Model | 1756-PA75R |
| Manufacturer | Allen‑Bradley (Rockwell Automation) |
| Product Type | Redundant AC Power Supply |
| Input Voltage Range | 85 – 265 V AC (Auto‑sensing) |
| Input Frequency | 47 – 63 Hz |
| Rated Output Power | 75 W (at 60 °C) |
| Output Voltages & Currents | 5.1 V DC @ 13 A, 3.3 V DC @ 4 A, 24 V DC @ 2.8 A, 1.2 V DC @ 1.5 A |
| Hold‑up Time | 2 cycles (at 50/60 Hz) |
| Inrush Current (max) | 20 A |
| Operating Temperature | 0 °C to 60 °C (32 °F to 140 °F) |
| Dimensions (H × W × D) | 175 mm × 145 mm × 137 mm (6.9 in × 5.7 in × 5.4 in) |
| Weight | 1.45 kg (3.2 lb) |
| Cooling Method | Natural convection (fanless) |
| Redundancy Support | Yes (requires 1756-PSCA2 adapter and second 1756-PA75R) |
Main Features and Advantages
N+1 Redundant Power Architecture: The defining feature of the 1756‑PA75R is its built‑in support for redundant operation. When used in conjunction with a second 1756‑PA75R unit and the 1756‑PSCA2 chassis adapter, the system provides true load‑sharing N+1 redundancy. Both power supplies operate in parallel, sharing the load current. In the event of a failure in one unit, the other automatically picks up the entire chassis load without any disruption to the ControlLogix processor or I/O modules. This design effectively removes the power supply as a single point of failure, which is critical for applications where unscheduled downtime is unacceptable.Wide Input Voltage Range and Rugged Design: The 1756‑PA75R is built for real‑world industrial environments. It accepts a wide input voltage range of 85–265 V AC, making it compatible with unstable or fluctuating power grids commonly found in remote industrial sites. Its fanless design relies on natural convection cooling, which eliminates a common mechanical failure point (the fan) and allows for silent, reliable operation. The unit is rated for continuous operation at temperatures up to 60 °C, ensuring stability even in hot control cabinet environments. Additionally, the 1756‑PA75R provides comprehensive status monitoring through LED indicators and an annunciator relay output, enabling quick visual diagnostics and integration into plant‑wide alarm systems for proactive maintenance.
Application Field
The Allen‑Bradley 1756‑PA75R is the preferred power solution for industries where system uptime is directly tied to safety, production throughput, or financial performance. In the Oil & Gas sector, it is extensively used in offshore platforms, pipeline compressor stations, and refinery critical control systems, where a power interruption could lead to hazardous situations or massive revenue loss. Similarly, in Power Generation plants, the 1756‑PA75R ensures uninterrupted power to turbine control systems and generator excitation controls, preventing costly grid instability or equipment damage.Beyond these heavy process industries, the 1756‑PA75R is also deployed in critical infrastructure such as Water and Wastewater treatment facilities for SCADA and pump control, and in the Chemical and Pharmaceutical industries for batch process control where recipe integrity must be maintained. Any ControlLogix‑based application that utilizes a redundant processor chassis (1756‑L7x) will typically be specified with the 1756‑PA75R redundant power system to maintain a consistent level of fault tolerance throughout the entire control architecture.
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