1756-PA75K Allen-Bradley ControlLogix AC Power Supply 75W

1756-PA75K | ControlLogix AC Power Supply Overview

The Allen-Bradley 1756-PA75K is an AC power supply module for compatible Rockwell Automation ControlLogix chassis. It converts incoming AC power into the DC power required by chassis backplane components.

Designed for installation on the left side of a compatible 1756 chassis, this module supplies multiple DC output rails. Its rated output reaches 75 W across the specified 0–60°C operating range.

The 1756-PA75K ControlLogix power supply accepts a nominal 120–240 VAC input and supports a wider 85–265 VAC range. Its 47–63 Hz input frequency supports common industrial AC power systems.

This model is a non-redundant power supply. Engineers should calculate chassis power demand and verify each module's current requirements before selecting a replacement.

Technical Specifications at a Glance

Manufacturer	Rockwell Automation
Brand	Allen-Bradley
Catalog Number	1756-PA75K
Product Family	ControlLogix
Module Type	AC Power Supply Module
Power Supply Design	Non-redundant
Nominal Input Voltage	120–240 VAC
Input Voltage Range	85–265 VAC
Input Frequency	47–63 Hz
Maximum Input Power	100 W / 100 VA, according to supplied specifications
Rated Output Power	75 W at 0–60°C, according to supplied specifications
Maximum Inrush Current	20 A
Output Capacity at 1.2 VDC	1.5 A
Output Capacity at 3.3 VDC	4 A
Output Capacity at 5.1 VDC	13 A
Output Capacity at 24 VDC	2.8 A
Hold-Up Time at 85 VAC, 60 Hz	2 cycles, according to supplied specifications
Hold-Up Time at 120 VAC, 60 Hz	6 cycles, according to supplied specifications
Hold-Up Time at 220 VAC, 60 Hz	20 cycles, according to supplied specifications
Rated Isolation Voltage	250 VAC continuous, according to supplied specifications
Power Dissipation	85.3 BTU/hr, according to supplied information
Installation Position	Left side of the compatible 1756 chassis
Compatible Chassis Listed	1756-A4, 1756-A7, 1756-A10, 1756-A13, 1756-A17; verify series compatibility
Recommended Wire	14 AWG solid or stranded copper, rated for 90°C
Enclosure Type	Open-style
Operating Temperature	0–60°C (32–140°F)
Approximate Dimensions	140 × 112 × 145 mm (5.51 × 4.41 × 5.71 in.)
Approximate Weight	Approximately 1.0–1.1 kg, depending on the supplied specification

Engineering note: The supplied source lists slightly different output power and weight figures. Confirm the exact catalog revision and official documentation before final design approval.

Power Architecture and System Value

• Multiple DC output rails: Supplies the chassis backplane through specified 1.2 VDC, 3.3 VDC, 5.1 VDC, and 24 VDC output capacities.
• Wide AC input range: Accepts 85–265 VAC within the specified operating requirements.
• Input disturbance tolerance: Hold-up time helps bridge brief input interruptions within the specified conditions.
• Chassis-mounted design: Installs on the left side of a compatible 1756 ControlLogix chassis.
• Overcurrent protection: Supplied information describes overcurrent protection and a non-replaceable fuse.

Calculate the actual chassis load before commissioning. Do not treat the total wattage as a substitute for checking each DC output rail.

Suitable Equipment and Industrial Applications

• ControlLogix PLC cabinets: Supply power to compatible controller chassis and installed modules.
• Manufacturing lines: Support PLC-based machine sequencing, conveyor control, and production equipment.
• Process automation: Power compatible chassis used for monitoring, control, and instrument integration.
• Utilities and infrastructure: Support compatible ControlLogix systems in pumping, water treatment, and facility automation.
• Industrial equipment upgrades: Replace a matching power supply after verifying chassis compatibility and electrical demand.

This module supplies chassis power. It does not independently provide PLC logic, analog measurement, or network communication functions.

Installation and Commissioning Procedure

1. Verify the catalog number: Match the complete 1756-PA75K designation and the required hardware revision.
2. Confirm chassis compatibility: Check the chassis model and series against the manufacturer's documentation.
3. Calculate backplane demand: Compare the installed modules' current requirements with each available DC output rating.
4. Isolate incoming power: Apply site lockout procedures before removing or installing the power supply.
5. Inspect wiring: Check conductor size, insulation rating, terminals, grounding, and incoming AC voltage.
6. Install the module: Mount the power supply in its designated left-side chassis position.
7. Restore power safely: Follow the manufacturer's startup sequence and verify supply status indications.
8. Validate operation: Check controller startup, module status, and backplane communication.

Never insert or remove the power supply under power unless the exact hardware and procedure explicitly permit it. Follow site electrical safety requirements and the manufacturer's installation manual.

Fault Diagnosis and Maintenance

• Chassis fails to start: Measure incoming AC voltage and inspect supply connections and protective devices.
• Repeated controller resets: Review input voltage stability, inrush conditions, and chassis power demand.
• Multiple module faults: Check the power supply and backplane before replacing individual I/O modules.
• Unexpected shutdowns: Compare event logs with power interruptions and facility electrical disturbances.
• Excessive cabinet temperature: Inspect ventilation, surrounding heat sources, and installed module loading.
• Intermittent operation: Check terminal tightness, wiring condition, and incoming power quality under approved procedures.

Field example: Several chassis modules report faults after a production line starts. An engineer checks incoming AC voltage and the backplane load before replacing the controller.

If the supply repeatedly loses output, inspect the input source and chassis demand first. A damaged supply may require replacement, but overload or unstable incoming power can cause similar symptoms.

Selection and Compatibility Checklist

• Catalog number: Confirm that the required part is 1756-PA75K rather than a similar power supply model.
• Input power: Verify the site's AC voltage and frequency against the specified range.
• Chassis series: Check the exact chassis model and revision for compatibility.
• Load calculation: Confirm that each DC output rail can support the installed modules.
• Mounting position: Ensure that the chassis has the required left-side power supply position.
• Redundancy requirements: This model is non-redundant. Select an approved architecture if the application requires redundant power.
• Environmental requirements: Check cabinet temperature, ventilation, and installation conditions.

Environmental Ratings and Compliance

• Operating temperature: 0–60°C under the supplied specifications.
• Input frequency: 47–63 Hz.
• Wire specification: 14 AWG copper conductors rated for 90°C, according to the supplied information.
• Enclosure: Open-style; install inside a suitable protective enclosure.
• Pollution and installation category: Verify the applicable environmental ratings against the official technical documentation.
• Certifications: Confirm applicable UL, CSA, CE, and hazardous-location approvals for the exact catalog number and revision.

Do not assume a certification applies to every installation. Verify the product label, manufacturer documentation, and local electrical requirements before commissioning.

Packaging, Shipping, and Warranty

• Package contents: 1 × Allen-Bradley 1756-PA75K AC power supply module, according to the confirmed order.
• Accessories: Additional parts or documentation are included only when stated in the order.
• Shipping carriers: FedEx, UPS, and DHL, subject to destination and service availability.
• Processing target: 24–48 hours after order confirmation, subject to stock verification.
• Warranty: 12-month warranty under Global PLC Spare HUB's applicable sales terms.

Contact our team to confirm availability, packaging details, shipping arrangements, and warranty coverage before ordering.

Global PLC Spare HUB's Insight

Power supply selection requires more than matching the AC input voltage. Engineers should calculate backplane demand across every DC output rail.

For example, a chassis may restart when several high-load modules operate together. The engineer should compare the installed module loads with the supply's individual current limits.

Input voltage also deserves attention during startup. A supply may experience a brief voltage drop when other equipment starts on the same circuit.

Check incoming voltage, grounding, wiring integrity, and chassis loading before concluding that the power supply has failed. These checks help separate source problems from module faults.

Frequently Asked Questions

Q1: How do I calculate whether this power supply can support my existing chassis?

List every installed module and its current requirements for each DC rail. Compare the totals against the power supply ratings and the chassis compatibility documentation.

Q2: Why can a power supply show normal input voltage while the controller still resets?

Check transient voltage drops, chassis loading, terminal connections, and individual output requirements. A normal idle reading may not reveal a problem under peak load.

Q3: Can I use the 1756-PA75K where a redundant power architecture is required?

This model is non-redundant. Review the system availability requirements and select a manufacturer-approved redundant solution when the application requires it.

Q4: What should I verify when replacing a similar-looking ControlLogix power supply?

Compare the complete catalog number, AC input range, DC output ratings, chassis series, mounting requirements, and applicable hardware documentation before installation.

Q5: Which details should I provide to help identify the right replacement?

Provide the existing power supply label, chassis catalog number, incoming AC voltage, installed module list, and required quantity. These details help our team review compatibility and prepare a quotation.

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