## FNQ-R-5: Technical Overview The **FNQ-R-5** is a high-performance, industrial-grade fuse designed specifically for control circuit protection. It belongs to the **Limitron™** family manufactured by Eaton (Bussmann Series). ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Model Number** | FNQ-R-5 | | **Current Rating** | 5 Amperes | | **Voltage Rating (AC)** | 600 Vac | | **Interrupting Rating** | 200,000 Amps (200 kA) RMS Symmetrical | | **Fuse Class** | Class CC | | **Response Characteristic** | Time-Delay (Slow-Blow) | | **Dimensions** | 13/32" x 1-1/2" (10.3mm x 38.1mm) | --- ### 2. Functional Characteristics The FNQ-R-5 is engineered with specific electronic behaviors to handle inductive loads: * **Time-Delay Property:** This fuse is designed to withstand temporary "inrush" currents (surges) that occur when motors or transformers start up, preventing "nuisance tripping." * **Current Limiting:** It is a rejection-style fuse, meaning it can physically limit the amount of peak current let-through during a short circuit, protecting sensitive downstream components. * **Rejection Feature:** As a Class CC fuse, it has a unique physical "rejection tip" on one end. This prevents the installation of fuses with lower voltage ratings or lower interrupting capacities into the same fuse holder. --- ### 3. Common Applications The FNQ-R-5 is typically found in industrial control panels and motor control centers (MCCs). Its primary uses include: 1. **Control Transformers:** Protecting the primary side of small control power transformers. 2. **Solenoids:** Handling the high initial current required to energize electromagnetic coils. 3. **Inductive Loads:** Any circuit where a standard "fast-acting" fuse would blow due to brief startup surges. 4. **Branch Circuit Protection:** Providing high-level safety for specialized industrial equipment. --- ### 4. Construction Details The device is built to survive harsh industrial environments: * **Body Material:** Melamine or Fiber tube for high heat resistance. * **End Caps:** Nickel-plated brass for high conductivity and corrosion resistance. * **Internal Element:** A specialized alloy designed to melt at precise thermal thresholds while providing the necessary delay for surges.