Allen-Bradley 140M-C2T-B10 Bulletin 140M Motor Protection Circuit Breaker

Product Overview

The Allen-Bradley 140M-C2T-B10 serves as a high-precision, Frame C Motor Protection Circuit Breaker (MPCB) within the industry-standard Bulletin 140M family. This molded case control component provides isolated, standalone defense for fractional-horsepower industrial motors against thermal overloads and instantaneous short circuits.

We supply this component strictly as a 100% brand new, original factory-sealed unit to ensure uncompromised factory calibration, clean internal switching mechanism linkages, and pristine contact surfaces for safety-critical branch circuit deployments.

Technical Specifications

The table below logs the precise structural design parameters, electrical frame capacities, and trip envelopes of the device:

Engineering Advantages

• Safeguards Sensitive Low-Current Windings: The highly specialized 0.63A to 1.0A thermal adjustment envelope protects fractional motors that typically suffer rapid burnout during minor overload conditions. The responsive bi-metal design senses minute current elevations, separating the contacts before the thermal energy warps the motor's internal winding insulation.

• Consolidates Control Panel Footprint: This single Frame C unit combines the functional roles of a discrete disconnect switch, a short-circuit magnetic limiter, and an overload relay into one micro-enclosure. This integration reduces vertical DIN rail utilization, allowing panel builders to deploy dense rows of motor starters inside shallow, space-constrained terminal boxes.

• Suppresses Vibration-Induced Nuisance Tripping: High-retention internal latching mechanics hold the internal spring assemblies rigidly in place. This heavy-duty frame design isolates the internal trip elements from the continuous shocks and structural micro-vibrations generated by adjacent high-power contactors and heavy machinery frames.

FAQs

• How do technicians properly calibrate the adjustable thermal range dial on the front of the breaker?

  Technicians must align the front-facing adjustment screw to match the exact Full Load Amps (FLA) rating stamped on the target motor's factory nameplate. Do not set the dial higher than the motor's nameplate FLA to eliminate nuisance trips, as this practice bypasses the tight thermal boundaries required to prevent stator core damage.

• What are the specific installation requirements for integrating this Frame C breaker onto a standard DIN rail?

  The breaker snaps directly onto standard 35mm top-hat DIN rails without requiring auxiliary tools. To ensure optimal natural convection cooling through the top and bottom ventilation slots, engineers must maintain a minimum vertical clearance of 50mm above and below the breaker body inside the enclosure.

• Does this breaker handle single-phase fractional motor loops as well as three-phase loads?

  Yes. While engineered primarily for three-phase circuits, this MPCB protects single-phase loads perfectly. However, to prevent the differential phase-loss logic from causing a premature trip, technicians must wire the single-phase circuit in series through all three pole paths of the breaker.