## FNQ-R-2-1/2 Fuse Technical Overview The **FNQ-R-2-1/2** is a high-performance industrial fuse belonging to the **Limitron™ CC Series**. It is specifically designed as a "Time-Delay" fuse to handle high inrush currents without nuisance tripping, while providing superior protection for sensitive branch circuits. --- ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Model Number** | FNQ-R-2-1/2 (or FNQ-R-2.5) | | **Amperage Rating** | 2.5 Amps | | **Voltage Rating (AC)** | 600 Vac | | **Interrupting Rating** | 200,000 Amps (RMS Symmetrical) | | **Fuse Class** | Class CC | | **Response Characteristic** | Time-Delay (Slow-Blow) | | **Body Material** | Melamine (Fiberglass) tube | | **Termination Style** | Ferrule (Rejection style) | --- ### 2. Physical Design Features The FNQ-R series features specific physical characteristics that ensure safety and compatibility: * **Rejection Tip:** The "R" in the model name indicates a physical rejection feature. This prevents a lower-rated fuse (like a standard midget fuse) from being installed in a Class CC fuse holder, ensuring the circuit maintains its high interrupt rating. * **Compact Size:** Standardized dimensions of **13/32" x 1-1/2"** (approx. 10mm x 38mm). * **Durable Construction:** Built with a melamine tube and nickel-plated brass endcaps to withstand harsh industrial environments. --- ### 3. Electronic Functionality The FNQ-R-2-1/2 is engineered for specific electronic protection tasks: 1. **High Inrush Handling:** The time-delay mechanism allows the fuse to ignore the brief, high-current spikes associated with **Control Transformers** and **Small Motors** during startup. 2. **Current Limitation:** It is a "Current-Limiting" fuse. In the event of a catastrophic short circuit, it reacts fast enough to stop the current before it reaches its full peak, protecting downstream components from thermal and magnetic stress. 3. **Branch Circuit Protection:** It meets UL requirements for branch circuit protection, making it suitable for primary and secondary protection of control power transformers. --- ### 4. Common Applications * Primary protection of control transformers. * Solenoids and inductive loads. * Small motor branch circuits. * Industrial control panels (UL 508A compliant). ---