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MS26574-3 – Klixon Aviation 3 Amp Push-Pull Circuit Breaker
Available now on the Airparts.aero Marketplace.
Overview
The MS26574-3 is a military-standard, single-pole, push-pull thermal circuit breaker, a flight-critical component engineered by Klixon (Sensata Technologies) for the ultimate protection of aircraft electrical systems. This 3-amp breaker is designed to provide precise, repeatable overcurrent protection in a compact, panel-mount package. Its iconic push-pull design allows it to function as both a protective device and a manual switch. Built to the most stringent military specifications, the MS26574 is a highly reliable and universally adopted circuit breaker found in the panels of countless military and commercial aircraft worldwide.
Key Features
Push-Pull (Pull-Off) Actuation: Features the classic push-pull button actuator. Pulling the button manually opens the circuit, allowing it to be used as a switch to de-energize a system for maintenance. Pushing the button resets the breaker after an overcurrent trip.
Trip-Free Design: A critical safety feature, the "trip-free" mechanism ensures the internal contacts cannot be forcibly held closed against an overcurrent or short-circuit condition. The breaker will remain tripped internally, even if the button is held in, until the fault is cleared.
Thermal Trip Mechanism: Utilizes a precisely calibrated, thermally responsive bimetallic element. This design provides a time-delayed trip on minor overloads (preventing nuisance trips from motor inrush currents) while reacting very quickly to dangerous high-amperage short circuits.
High Vibration & Shock Resistance: Engineered and constructed to withstand the severe vibration, shock, and environmental conditions of military and commercial aerospace applications, ensuring it will not trip inadvertently or fail under stress.
MS Certified Standard: Manufactured in strict accordance with the MIL-PRF-26574 specification, guaranteeing its performance, reliability, and environmental ratings are certified for the most demanding flight-critical applications.
Technical Specifications
Standard: MS26574 (MIL-PRF-26574)
Full Part Number: MS26574-3
Alternate Part Number: 7274-2-3
Component Type: Thermal Circuit Breaker
Actuator Style: Push-Pull (Pull-Off)
Poles: 1
Current Rating: 3 Amps
Voltage Rating: 120 VAC / 30 VDC
Mounting Style: Threaded Bushing
Termination Style: Screw Terminals
Interrupt Capacity: High interrupt rating per military specification.
Aircraft Compatibility
The MS26574-3 is a universal electrical component used extensively across a massive range of military, commercial, and general aviation aircraft. It is the specified breaker for countless low-amperage circuits.
Common Aircraft Platforms:
Textron Aviation, Bombardier, Embraer, Gulfstream
Boeing, Airbus
Countless military fighters, transports, and helicopters.
Common Applications:
Avionics & Instrumentation: Protecting individual avionics units, instrument lighting, and flight deck control panels.
Control Circuits: Used in the control circuits for flaps, landing gear, and other systems that use relays and logic controllers.
Utility Circuits: Protecting various utility and cabin electrical circuits.
Applications
The MS26574-3 is the professional standard for reliable circuit protection and control:
Circuit Protection: Its primary function is to automatically disconnect a circuit from its power source when it experiences a sustained overload or a short circuit, preventing wire overheating and fire.
System Switching: The pull-off actuator allows pilots and maintenance crews to use the breaker as a manual ON/OFF switch for the protected circuit, a required function for many checklists and maintenance procedures.
Fault Indication: When the breaker trips, the white button extends from the body, providing a clear visual and tactile indication that a fault has occurred on that specific circuit.
Why Choose MS26574-3?
The safety and reliability of an aircraft's electrical system depend entirely on the quality of its circuit protection. The Klixon MS26574-3 is a globally recognized, military-specification component with a multi-decade history of proven performance in the most demanding environments. Its trip-free design is a critical safety feature that prevents catastrophic failures. By choosing a genuine MS-standard Klixon breaker, you are ensuring that your electrical circuits are protected by a component with a known, repeatable trip curve, a high interrupt rating, and the robust construction required for aviation.Order Your Klixon MS26574-3 Circuit Breakers Now
Protect your aircraft's valuable electrical and avionics systems with certified, military-specification hardware. Visit Airparts.aero to order your Klixon MS26574-3 circuit breakers today.
The MS26574-3 thermal circuit breaker operates on the principle of differential expansion. Current flows through a bimetallic strip composed of two metals with different thermal expansion coefficients bonded together. As current increases, the strip heats up (P=I2R). An overcurrent condition causes the strip to heat significantly, forcing it to bend due to the differential expansion of the two metals. This bending action unlatches a spring-loaded mechanism, causing the contacts to snap open and interrupt the flow of current. This thermal principle provides an inverse time characteristic: a slight overload will cause a slow heating and a delayed trip, whereas a major short circuit will cause rapid heating and a near-instantaneous trip. This prevents unnecessary tripping on temporary inrush currents while providing robust protection against dangerous faults.
Note: This is a flight-critical electrical safety device. Installation must be performed by a certified A&P mechanic or avionics technician. Always ensure the breaker's amperage rating is correct for the circuit's wire gauge and the power requirements of the connected equipment, as specified by the aircraft manufacturer. Terminals must be torqued to the specified value.
