## Overview of the FNQ-R-15 Fuse The **FNQ-R-15** is a high-performance, time-delay cartridge fuse belonging to the **CC-TRON™** series manufactured by Bussmann (Eaton). It is specifically designed to meet the protection requirements of control transformers and circuits with high inrush currents. --- ### 1. Technical Specifications The following table summarizes the key electrical and physical characteristics: | Property | Specification | | :--- | :--- | | **Current Rating** | 15 Amperes | | **Voltage Rating (AC)** | 600 Vac | | **Interrupting Rating** | 200,000 Amps (RMS Symmetrical) | | **Fuse Class** | Class CC | | **Response Time** | Time-Delay (Slow-Blow) | | **Material** | Melamine tube with Nickel-plated brass endcaps | | **Rejection Feature** | Yes (Physical rejection tip) | --- ### 2. Key Electronic Features #### A. Time-Delay Characteristic Unlike "fast-acting" fuses, the FNQ-R-15 is engineered to handle temporary surges. This is crucial for electronic components like **transformers** or **solenoids** that draw a large "inrush" current when first powered on. The fuse will not blow during these brief spikes but will trip if a sustained overcurrent occurs. #### B. Current Limiting (Class CC) As a Class CC fuse, it is "current-limiting." In the event of a catastrophic short circuit, the fuse reacts fast enough to prevent the current from reaching its full destructive peak. This protects sensitive downstream electronic hardware from thermal and magnetic stress. #### C. High Interrupting Rating With a **200kA AIC** (Ampere Interrupting Capacity), this fuse can safely clear very high fault currents without exploding or arcing over, which is a standard requirement for industrial control panels. --- ### 3. Common Applications * **Control Transformers:** Protecting the primary side of industrial control power transformers. * **Motor Control Circuits:** Providing branch circuit protection. * **Solenoids:** Handling the inductive load spikes. * **Lighting Loads:** Specifically those using ballasts with high startup currents. --- ### 4. Comparison: FNQ vs. FNQ-R It is important to note the difference in physical design: * **FNQ:** Standard midget fuse (10x38mm) without a rejection tip. * **FNQ-R:** Includes a **rejection tip** (a small physical protrusion on one end). This ensures that the fuse can only be inserted into a Class CC holder, preventing a lower-rated fuse from being used in a high-voltage circuit.