140M-K8P-D40 Bulletin 140M K-Frame Molded Case Circuit Breaker | Allen Bradley

Product Overview

The Allen Bradley 140M-K8P-D40 serves as a high-capacity motor protection and power distribution solution within the Bulletin 140M family. This K-Frame Molded Case Circuit Breaker (MCCB) handles heavy-duty loads up to 400 Amps, providing essential instantaneous magnetic trip protection for large-scale industrial motors and branch circuits. While the manufacturer has officially discontinued this series, we provide this unit as 100% Brand New original equipment to ensure your legacy systems maintain peak safety and performance standards.

Technical Specifications

Engineering Advantages

• Precision Short-Circuit Protection: The integrated magnetic-only trip mechanism monitors current surges instantly. With an adjustable or fixed range between 2000 and 4000 Amps, the breaker interrupts massive faults before they reach downstream equipment, preventing catastrophic motor failure.

• High Power Density: The K-Frame design packs a 400 Amp capacity into a relatively compact 8.80 lb housing. This allows engineers to upgrade power distribution in existing control panels without requiring extensive mechanical modifications or larger enclosures.

• Legacy System Support: As a discontinued component, the 140M-K8P-D40 facilitates direct "drop-in" replacement for failed units. This eliminates the need for expensive system re-engineering or the installation of newer, incompatible frames that would require updated mounting hardware and busbars.

• Optimized for 90 HP Motors: Specifically rated for 90 HP at 480V, this breaker provides the specific inrush current headroom required for large motor startups, preventing nuisance tripping during high-torque acceleration phases.

FAQs

• Since this model is discontinued, is this a refurbished unit?

  No. We guarantee this unit is 100% Brand New original stock. It has never been installed or energized. While Rockwell Automation may no longer produce this frame, our supply consists of factory-sealed surplus inventory.

• Can I use the 140M-K8P-D40 as a main disconnect?

  Yes. This Molded Case Circuit Breaker functions effectively as a branch circuit protector or a main disconnect for motor control centers, provided the 400 Amp rating and magnetic trip characteristics align with your local electrical code requirements.

• What should I check before installing this K-Frame breaker?

  Ensure the lug connections and busbar spacing match the K-Frame footprint. Verify that the magnetic trip range (2000-4000A) appropriately protects your specific motor load based on its Locked Rotor Amps (LRA) to ensure the breaker does not trip during normal startup.

• How does the magnetic-only trip benefit motor circuits?

  In motor applications, a separate overload relay typically handles thermal protection. Using a magnetic-only breaker like the 140M-K8P-D40 prevents "double-protection" conflicts, allowing the breaker to focus exclusively on interrupting high-current short circuits.