The **FNQ-R-4** is a high-performance, current-limiting time-delay fuse commonly used in industrial electrical systems. It belongs to the **Bussmann CC-TRON™** series. Below is a detailed breakdown of its electronic specifications and applications. --- ### 1. Technical Specifications The following table highlights the core electrical characteristics of the FNQ-R-4: | Feature | Specification | | :--- | :--- | | **Amperage Rating** | 4 Amps | | **Voltage Rating (AC)** | 600 Vac | | **Interrupting Rating** | 200,000 Amps (RMS Symmetrical) | | **Fuse Class** | Class CC | | **Type** | Time-Delay (Slow Blow) | | **Rejection Feature** | Yes (Prevents installation of lower-rated fuses) | | **Body Material** | Melamine tube with Nickel-plated brass endcaps | --- ### 2. Key Electronic Features #### A. Time-Delay Mechanism Unlike "Fast-Acting" fuses, the FNQ-R-4 is designed with a **Time-Delay** characteristic. This allows the fuse to withstand temporary "inrush" currents (spikes that occur when a motor or transformer starts) without blowing. If the overcurrent persists, the fuse will open to protect the circuit. #### B. Rejection Functionality As a **Class CC** fuse, it features a physical "rejection tip" on one of its endcaps. This ensures that the fuse can only be inserted into a Class CC fuse holder, preventing someone from accidentally replacing it with a fuse that has a lower interrupting rating or different voltage capacity. #### C. High Interrupting Capacity With a **200kA AIC** (Ampere Interrupting Capacity), this fuse is capable of safely handling massive short-circuit currents without exploding or arcing, which is critical for industrial safety. --- ### 3. Common Applications The FNQ-R-4 is specifically engineered for circuits with inductive loads. Typical use cases include: 1. **Control Transformers:** Protecting the primary side of industrial control transformers. 2. **Motor Branch Circuits:** Providing specialized protection for small horsepower motors. 3. **Solenoids:** Managing the high start-up current required to engage solenoid valves. 4. **Lighting Loads:** Used in specific high-voltage lighting ballasts. --- ### 4. Dimensional Data * **Diameter:** 13/32 inches (approx. 10.3 mm) * **Length:** 1-1/2 inches (approx. 38.1 mm) ---