Product Overview

The Allen-Bradley 1768-PA3 is a CompactLogix power supply module. This power supply provides backplane power to energize connected modules. It operates on dual inputs of 85 to 265V AC or 108 to 132V DC. The Allen-Bradley 1768-PA3 is exclusively used with the 1768 product family. Users trust this power supply for reliable CompactLogix system power distribution.

Technical Specifications

The 1768-PA3 delivers robust power with comprehensive protection features. Below are the complete technical details.

General Specifications

• Manufacturer: Rockwell Automation for industrial control reliability.

• Brand: Allen-Bradley for CompactLogix compatibility.

• Part Number: 1768-PA3 for precise identification.

• Product Line: CompactLogix family.

• Product Type: Power Supply Module.

• Module Type: AC Power Supply Module.

• UPC: 10612598307569 for universal product identification.

• Enclosure: None (open-style).

• Shipping Weight: 2 lbs (approximately 0.9 kg).

• Shipping Dimensions: 8 x 8 x 5 inches.

Input Power Specifications

• Input Power (AC): 85 to 265V AC.

• Input Power (DC): 108 to 132V DC.

• Input Frequency Range: 47 to 63 Hz (AC operation).

• Maximum Input Power: 120 VA / 120 W.

• Efficiency (Typical): 75%.

• Power Dissipation (Maximum): 30 W.

• Power Consumption: 33.6 Watts.

Backplane and Output Specifications

• Backplane Current: 1.4 Amps at 24 Volts.

• Output Purpose: Provides backplane power to attached modules.

• No Output Power: Does not supply power to output modules.

• Power Supply Distance: Important for module placement in rack.

Inrush Current Specifications

• Inrush Current (85 to 132V AC, Nominal): 25 A.

• Inrush Current (85 to 132V AC, Maximum): 50 A.

• Inrush Current (195 to 265V AC, Nominal): 50 A.

• Inrush Current (195 to 265V AC, Maximum): 80 A.

• Inrush Current (108 to 132V DC, Nominal): 25 A.

Protection Specifications

• Internal Overcurrent Protection: Non-replaceable fuse soldered in place.

• Recommended External Overcurrent Protection: 4 to 6 A at 28.5 to 36.7 A²S.

• Integrated Overcurrent Protection: 15 A.

• Isolation Voltage: 30 Volts Continuous.

• Wiring Category: Category 1 for power ports.

Wiring Specifications

• Wire Sizes: 14 to 22 AWG (stranded or solid copper).

• Wire Temperature Rating: 167°F (75°C) maximum.

• Maximum Isolation: 1.2 millimeters.

• Mounting Options: DIN rail or panel mount.

Compatibility and System Configuration

• Compatible Controllers: 1768-L43, 1768-L43S, 1768-L45, 1768-L45S.

• 1769 Compact I/O Support: Accommodates up to 8 modules in same bank.

• Power Supply Distance: Distance between 1769 I/O modules and controller.

• Important Note: Never install a 1769 power supply on a 1768 backplane.

LED Status Indicator

• LED Color (Normal): Green when power is applied.

• LED OFF: Check input power, shorts, overloads, or replace power supply.

• LED RED: Output to backplane is invalid, controller may need replacement, or communication/motion module may be defective.

• Diagnostics: Single LED for real-time status monitoring.

Environmental Specifications

• Enclosure Type: Open-style (requires installation in enclosure).

• Mounting: DIN rail or panel mount compatible.

Installation Guide

To install the Allen-Bradley 1768-PA3 correctly, begin by powering down the entire system. After that, choose a mounting method using either DIN rail or panel mount hardware. Once mounted, install a 1768 CompactLogix controller in the same bank as the power supply.

Moving on to wiring, use 14 to 22 AWG stranded or solid copper wire rated at 167°F (75°C). Subsequently, connect the input power source to the appropriate AC or DC terminals. For AC operation, ensure the frequency stays between 47 and 63 Hz. In addition, install external overcurrent protection rated at 4 to 6 A with 28.5 to 36.7 A²S characteristics.

Before powering up, verify that no 1769 power supply is installed on the 1768 backplane. Then, apply input power and observe the LED status indicator. If it turns green, normal operation is confirmed. Furthermore, calculate the power supply distance rating to ensure all modules receive adequate backplane power. When using 1769 Compact I/O modules, limit them to eight modules in the same bank. Finally, if the LED turns red, check for a defective controller or communication module.

Installation Notes

• The power supply provides 1.4A at 24V DC to the backplane.

• Internal overcurrent fuse is non-replaceable and soldered in place.

• Maximum input power is 120 VA or 120 W depending on voltage.

• Typical efficiency is 75% for energy-conscious operation.

• The power supply does not supply output power to field devices.

Packaging List

This unit ships as a new and original product.

• Allen-Bradley 1768-PA3 CompactLogix Power Supply Module

• DIN rail mounting clip (pre-attached)

• Product data sheet with installation guide

• Anti-static factory packaging box

Frequently Asked Questions (FAQ)

1. What input voltages does the 1768-PA3 support?
The Allen-Bradley 1768-PA3 supports dual inputs of 85 to 265V AC or 108 to 132V DC. This flexibility suits various power sources worldwide.

2. Can I use a 1769 power supply on a 1768 backplane?
No, never install a 1769 power supply on a 1768 CompactLogix backplane. The 1768-PA3 is exclusively designed for the 1768 product family.

3. What is the backplane current output of the 1768-PA3?
The 1768-PA3 provides 1.4 Amps at 24 Volts DC to the backplane. This energizes all modules connected to the CompactLogix system.

4. How many 1769 Compact I/O modules can the 1768-PA3 support?
The Allen-Bradley 1768-PA3 accommodates up to eight 1769 Compact I/O modules in the same bank. Proper power supply distance rating must be observed.

5. What does the red LED indicate on the 1768-PA3?
A red LED on the 1768-PA3 means the power output to the backplane is invalid. This could indicate a controller replacement need or a defective communication/motion module.