Overview
The Allen-Bradley 1756-PA75R is a redundant power supply module engineered for ControlLogix control systems. The 1756-PA75R provides 75 watts of reliable DC power output from a 120/240 VAC or 85–265 VAC input source, making it ideal for industrial automation applications that demand fault-tolerant operation. The redundant configuration supports automatic load sharing between two power supplies, ensuring uninterrupted system performance even during single power source failure.
Key Features
- Redundant power delivery with automatic chassis load sharing—two units operate in parallel for fault tolerance
- Wide input voltage range: 85–265 VAC at 47–63 Hz, or nominal 120/240 VAC
- Multiple DC output rails: 5.1V @ 13A, 3.3V @ 4A, 1.2V @ 1.5A, 24V @ 2.8A (max 75W combined)
- Rapid inrush current handling: 20 A maximum inrush current for stable initialization
- Hold-up time of 2 cycles at 60 Hz, maintaining voltage during brief AC interruptions
- Reinforced insulation at 250V continuous isolation, tested at 3250V DC per 60 seconds
- Open-style design (no protective enclosure) suitable for controlled industrial environments
- Status LEDs for real-time operational and fault indication
Technical Specifications
- Input Voltage Range: 85–265 VAC at 50/60 Hz
- Nominal Input Voltage: 120/240 VAC
- Input Frequency: 47–63 Hz
- Input Power (Maximum): 115 W, 120 VA
- Output Power (Maximum): 75 W @ 0–60°C (32–140°F)
- Maximum Inrush Current: 20 A
- Hold-Up Time: 2 cycles @ 60 Hz; 2 cycles @ 50 Hz
- Isolation Voltage: 250V continuous, reinforced insulation
- Annunciator Power: 240V AC/DC, 50 mA, resistive only
- Enclosure Type: Open-style (rack mount, no protective shell)
- Display Type: Status LEDs
- Operating Temperature: 0–60°C (32–140°F)
- Standards: CE, CSA, CUL, KC, MARINE, NRTL, RCM, UL
- Dimensions: 6.9 × 5.7 × 5.4 inches (17.5 × 14.5 × 13.7 cm)
Typical Applications
- Mission-critical manufacturing and process control systems requiring uninterrupted DC power to ControlLogix processors and I/O modules
- Redundant power architectures in multi-chassis ControlLogix configurations
- Automated packaging, assembly, and material handling equipment
- Food and beverage production facilities where power loss translates to product loss
- Pharmaceutical and life-sciences manufacturing with strict uptime requirements
- Oil and gas, chemical, and refinery instrumentation and control systems
Compatibility & Replacements
Compatible With
- ControlLogix 1756 Series A, B, C, and later chassis
- ControlLogix processors: 1756-L55, 1756-L73, 1756-L75, 1756-L83, and compatible models
- ControlLogix I/O modules and terminal bases in 1756 slots
- 1756-PSCA2 and 1756-PSCA2K passive chassis adapters for redundant supply management
- EtherNet/IP, ControlNet, and DeviceNet communication modules installed in ControlLogix chassis
- Studio 5000 Logix Designer and RSLogix 5000 engineering platforms
Replaces / Drop-In Replacement For
- Earlier Allen-Bradley 1756-PA75 Series A redundant power supplies (non-“R” variant)
- Verify exact compatibility with your system integrator before replacing; some legacy configurations may require chassis adapter modules
Works With
- Studio 5000 Logix Designer (Rockwell Automation engineering software)
- RSLogix 5000 (legacy; compatible with ControlLogix Series A/B/C)
- ControlLogix system configuration tools and chassis I/O documentation
- EtherNet/IP, ControlNet, and DeviceNet communication protocols supported at the backplane level
- Third-party SCADA and HMI platforms communicating via EtherNet/IP
