The **3AB5-R** is a specific model of a **fast-acting ceramic tube fuse** manufactured by Bel Fuse Inc. The "3AB" designation refers to the physical size and shape (industry standard), while the "R" indicates compliance with RoHS (Restriction of Hazardous Substances) standards. --- ### 1. Technical Specifications The following table outlines the key electrical and physical characteristics of the 3AB5-R fuse: | Feature | Specification | | :--- | :--- | | **Current Rating** | 5 Amperes (A) | | **Voltage Rating** | 250 Volts AC (VAC) | | **Fuse Type** | Fast-Acting / Fast Blow (F) | | **Body Material** | Ceramic | | **Size / Dimension** | 6.3mm x 32mm (1/4" x 1-1/4") | | **Interrupting Rating** | 200A @ 250V AC / 10kA @ 125V AC | | **Compliance** | RoHS 2 (Lead-Free) | | **Termination** | Cartridge (Ferrule) | --- ### 2. Physical Construction The 3AB series is constructed to handle higher pressures and temperatures than standard glass fuses. * **Ceramic Body:** Unlike glass fuses, the ceramic tube is opaque and filled with silica sand. This design helps to quench the arc produced when the fuse blows, preventing the casing from shattering during a high-current short circuit. * **Nickel-Plated Brass Caps:** Provide excellent conductivity and corrosion resistance at the contact points. * **Melting Element:** A precise wire or strip calibrated to melt instantly when the current exceeds 5A. --- ### 3. Key Differentiators Understanding why the 3AB5-R is chosen over other fuses: 1. **Fast-Acting vs. Time-Delay:** This fuse is designed to "blow" almost instantly (milliseconds) when an overload occurs. It is **not** suitable for inductive loads like motors that have high startup surges. 2. **High Breaking Capacity:** Because it is ceramic, it can safely interrupt much higher currents (up to 10,000 Amps at 125V) without exploding, compared to glass fuses (3AG series). 3. **Standard Form Factor:** The 6.3x32mm size is one of the most common fuse sizes in North America, making it easy to find replacement holders and clips. --- ### 4. Common Applications The 3AB5-R is typically found in industrial and high-end consumer electronics where safety and rapid disconnection are required: * Power Supplies (PSUs) * Industrial Control Panels * Test and Measurement Instruments * Server and Networking Equipment