Allen-Bradley 1756-PA50 – ControlLogix Standard AC Power Supply | ControlLogix Platform
Engineering Background
The 1756-PA50 is Rockwell Automation’s workhorse AC power supply for the ControlLogix 1756 chassis family. Designed to operate across a wide AC input range (85–265 V AC), it delivers a stable 10 A backplane output, making it the default choice for mid-to-large ControlLogix configurations where chassis slot density and mixed I/O loads demand reliable, regulated power. Its universal input range eliminates the need for external step-down transformers in most global installations, reducing BOM complexity and panel footprint.
Product Positioning
Konmask.com supplies the 1756-PA50 as verified surplus and new-surplus stock, sourced directly from decommissioned OEM lines and authorised distribution channels. Every unit undergoes functional inspection before dispatch. This makes the 1756-PA50 from Konmask the preferred procurement path for MRO engineers, system integrators, and plant maintenance teams who need a drop-in replacement without the lead times of new factory orders.
Complete Technical Specifications
| Parameter | Value |
|---|---|
| Catalog Number | 1756-PA50 |
| Platform | Allen-Bradley ControlLogix 1756 |
| Power Supply Type | Standard AC |
| AC Input Voltage Range | 85–265 V AC (universal) |
| AC Input Frequency | 47–63 Hz |
| AC Input Current (max) | 2.5 A @ 120 V AC / 1.5 A @ 240 V AC |
| Backplane Output Current | 10 A @ 5 V DC (backplane bus) |
| Auxiliary Output | 1.5 A @ 24 V DC (user auxiliary) |
| Power Dissipation (max) | 17 W |
| Inrush Current (max) | 20 A peak |
| Operating Temperature | 0 °C to +60 °C |
| Storage Temperature | -40 °C to +85 °C |
| Relative Humidity | 5–95% non-condensing |
| Chassis Compatibility | All 1756 ControlLogix chassis (4-, 7-, 10-, 13-, 17-slot) |
| Slot Occupancy | 1 slot (leftmost chassis slot) |
| Dimensions (H × W × D) | 147 mm × 45 mm × 144 mm |
| Weight | ~0.59 kg |
| Certifications | UL, CE, CSA, C-Tick |
| ATEX / Hazardous Location | Not rated (standard environment) |
| Firmware | No firmware — hardware-only module |
Proven Application Environments
- Discrete Manufacturing: Automotive assembly lines, stamping presses, and robotic welding cells running ControlLogix L6x/L7x/L8x controllers.
- Process Industries: Oil & gas upstream/midstream skids, chemical batch reactors, and water/wastewater SCADA panels where 24/7 uptime is non-negotiable.
- Material Handling: Conveyor sortation systems, palletisers, and AS/RS installations with high I/O slot counts requiring full 10 A backplane budget.
- Power Generation & Utilities: Substation automation and turbine control panels with 120/240 V AC utility feeds.
- MRO & Spare Parts: Direct drop-in replacement for failed or end-of-life 1756-PA50 units — no chassis reconfiguration required.
Engineering Advantages
- Universal AC Input: 85–265 V AC range covers North American 120 V, European 230 V, and industrial 208/240 V feeds without rewiring.
- Full 10 A Backplane Budget: Supports fully populated 17-slot chassis with mixed digital, analog, and communication modules.
- Auxiliary 24 V DC Output: Powers field sensors or relay coils directly from the supply, reducing external PSU count.
- Hot-swap Capable: Designed for chassis-level redundancy configurations when paired with a second 1756-PA50 in a redundant power supply chassis.
- LED Diagnostics: Onboard OK LED provides instant visual confirmation of healthy backplane power — no software required.
- Compact Form Factor: Single-slot occupancy preserves maximum I/O capacity in space-constrained panels.
System Architecture & Signal Flow
The 1756-PA50 occupies the dedicated power supply slot at the far left of any 1756 chassis. AC mains connect to the screw-terminal block on the module face. Internally, the supply converts AC input through a switching regulator to a regulated 5 V DC backplane bus and a 24 V DC auxiliary rail. The backplane bus distributes power to all controller, I/O, and communication modules seated in the chassis. The auxiliary terminal provides an isolated 24 V DC output for field device power. A single OK LED on the front face illuminates green when both rails are within specification. In a redundant power configuration, two 1756-PA50 units are installed in a 1756-RPSF redundant power supply chassis, with automatic failover if one supply faults.
Sourcing & Quality Verification
- Source: Verified surplus from decommissioned OEM production lines and authorised distribution channels — not grey-market or counterfeit.
- Inspection: Each unit is visually inspected for physical damage, label integrity, and terminal condition prior to listing.
- Functional Test: Units are bench-tested for correct output voltages (5 V DC backplane, 24 V DC auxiliary) and OK LED operation before dispatch.
- Packaging: Anti-static bag + foam-lined carton. ESD-safe handling throughout.
- Traceability: Serial number and date code recorded at time of inspection. Available on request.
- Warranty: 90-day Konmask operational warranty. DOA units replaced or refunded within 7 business days.
Procurement Process
- Confirm Compatibility: Verify your chassis catalog number (e.g., 1756-A17, 1756-A10) and existing power supply slot occupancy.
- Request Quote: Contact [email protected] for volume pricing, lead time, and availability confirmation.
- Place Order: Add to cart and complete checkout, or request a proforma invoice for bank transfer / corporate PO.
- Shipping: DHL / FedEx express available for international orders. Domestic CN orders ship same day if ordered before 14:00 CST.
- Receive & Verify: Inspect packaging integrity on arrival. Test OK LED on power-up before installing in live chassis.
Technical FAQ
Q: Can the 1756-PA50 power a fully loaded 17-slot chassis?
A: Yes. The 10 A backplane output is sufficient for a fully populated 17-slot chassis under typical mixed I/O loading. Verify total module current draw against the chassis power budget using Rockwell’s System Power Estimator tool.
Q: Is the 1756-PA50 compatible with ControlLogix L8x (v32+) controllers?
A: Yes. The power supply is hardware-agnostic and compatible with all ControlLogix controller generations including L6x, L7x, and L8x series.
Q: What is the difference between 1756-PA50 and 1756-PA75?
A: The 1756-PA75 provides a higher backplane output (13 A vs 10 A) for larger or more densely loaded chassis. The 1756-PA50 is the standard choice for most installations; the PA75 is recommended when total module current demand exceeds 10 A.
Q: Can I use two 1756-PA50 units for redundant power?
A: Yes, when installed in a 1756-RPSF redundant power supply chassis. Each supply independently powers the backplane; if one fails, the other maintains full operation without interruption.
Q: Do you provide a certificate of conformance or test report?
A: Yes, on request. Contact [email protected] with your order number after purchase.
Q: What is the lead time for international orders?
A: In-stock units ship within 1 business day. DHL Express international transit is typically 3–5 business days depending on destination customs clearance.
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