1768-PA3 Allen-Bradley CompactLogix Power Supply Module New

Product Overview

The 1768-PA3 is a high-performance CompactLogix power supply engineered to energize the 1768 backplane. It features a robust dual-input design, accepting both AC (85–265V) and DC (108–132V) voltage ranges. This module serves as the foundational energy source for 1768-L4x series controllers and associated expansion I/O. By providing 1.4A at 24V DC to the backplane, the 1768-PA3 ensures stable logic-side power for complex motion and communication tasks.

Technical Specifications

• Brand: Allen-Bradley / Rockwell Automation
• Model: 1768-PA3
• Product Line: CompactLogix 1768
• Input Voltage (AC): 85–265V AC (47–63 Hz)
• Input Voltage (DC): 108–132V DC
• Backplane Output: 1.4 Amps at 24 Volts
• Maximum Input Power: 120 VA / 120 W
• Efficiency: 75% Typical
• Inrush Current (AC): 50A @ 132V; 80A @ 265V
• Isolation Voltage: 30V Continuous
• Power Dissipation: 30 Watts (Max)
• Overcurrent Protection: Internal Soldered Fuse (Non-replaceable)
• Enclosure Type: Open-style (Mountable via DIN Rail or Panel)
• Wiring Specification: 14–22 AWG Stranded/Solid Copper

Global PLC Spare HUB's Insight

The 1768-PA3 is specifically designed for the "Power Side" of the 1768 architecture. A common engineering mistake is attempting to use 1769 power supplies on a 1768 backplane; they are physically and electrically incompatible. This module is the heart of the 1768-L43 and 1768-L45 systems, providing the necessary current for high-speed SERCOS motion modules.

Compatible Equipment & Application Scenarios

• Compatible Controllers: 1768-L43, 1768-L43S, 1768-L45, 1768-L45S.
• I/O Integration: Supports up to 8 modules of 1769 Compact I/O in the same bank.
• Motion Control: Ideal for multi-axis machinery using 1768-M04SE modules.
• Safety Systems: Powers GuardLogix 1768 safety processors for SIL3 applications.

Diagnostic Capabilities

• Solid Green LED: Normal operation; backplane power is stable and within range.
• LED OFF: Check input line voltage. This may indicate a tripped internal fuse or a primary power failure.
• Solid Red LED: Indicates a critical fault. Typically signifies invalid backplane output power or a hardware failure in the attached controller/communication module.

Shipping & Warranty Terms

• Warranty: 12-month comprehensive technical warranty.
• Handling: Ships within 24–48 hours of order confirmation.
• Global Express: Reliable delivery via FedEx, UPS, and DHL.
• Package Integrity: Professional anti-static packaging (Shipping Weight: 2 lbs).

Selection & Engineering Guide

• Distance Rating: Always verify the "Power Supply Distance Rating" for every 1769 I/O module added. If the module is too far from the 1768-PA3, voltage drops can cause erratic I/O behavior.
• Inrush Planning: Ensure your upstream breakers/fuses can handle the 80A peak inrush current at 265VAC to prevent nuisance tripping during system startup.

Expert FAQ

Why is my 1768-PA3 LED off even though I have 220V AC input?

The internal fuse may have blown. This fuse is soldered and non-replaceable. If the fuse is gone, the entire power supply module must be replaced to ensure system safety and compliance.

Can this module power 1769-series output devices directly?

No. The 1768-PA3 only provides logic-side backplane power. You must provide external power to the terminal blocks of your output modules for field device actuation.

What is the primary difference between Series A and Series B versions?

Series B often includes updated internal components for better heat dissipation and improved EMI resistance, though they remain functionally interchangeable for 1768 systems.

How do I handle the dual-voltage input during installation?

There is no manual toggle switch. The module is designed to handle the specified AC or DC ranges automatically. Ensure your wiring matches the terminal markings to prevent phase-to-ground faults.

Can I use a 1768-PA3 as a standalone power source for other 24V DC devices?

No. This power supply is proprietary to the CompactLogix 1768 backplane. It does not provide external 24V DC output terminals for auxiliary sensors or HMI units.

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