## FNQ-R-9 Fuse: Technical Specifications and Overview The **FNQ-R-9** is a high-performance, time-delay industrial fuse belonging to the **Bussmann series (Eaton)**. It is specifically designed as a "Class CC" fuse, which is known for its space-saving design and superior current-limiting capabilities. --- ### 1. Key Technical Specifications The following table outlines the core electronic and mechanical parameters of the FNQ-R-9: | Feature | Specification | | :--- | :--- | | **Current Rating** | 9 Amperes | | **Voltage Rating (AC)** | 600 Vac | | **Interrupt Rating** | 200,000 Amps (RMS Symmetrical) | | **Fuse Class** | Class CC | | **Response Characteristic** | Time-Delay (Slow Blow) | | **Material** | Melamine tube with Nickel-plated brass endcaps | | **Dimensions** | 13/32" x 1-1/2" (10.3mm x 38.1mm) | --- ### 2. Functional Characteristics The FNQ-R-9 is engineered for specific electronic behaviors: * **Time-Delay (Slo-Blo):** Unlike fast-acting fuses, the FNQ-R-9 can withstand temporary "inrush" currents. This is critical for inductive loads like motors or transformers that pull a high amount of current for a fraction of a second when starting up. * **Rejection Feature:** As a Class CC fuse, it features a unique physical rejection tip on one end. This ensures it can only be inserted into a Class CC fuse holder, preventing someone from accidentally replacing it with a fuse of lower interrupting capacity or different voltage ratings. * **Current Limiting:** It is highly current-limiting, meaning it reacts quickly during a massive short-circuit to "stop" the energy before it reaches its peak, protecting sensitive downstream components. --- ### 3. Common Applications The "R" in FNQ-R stands for **Rejection**, and these fuses are primarily used in the following scenarios: 1. **Control Transformers:** Protecting the primary side of control power transformers. 2. **Motor Branch Circuits:** Providing specialized protection where small horsepower motors are utilized. 3. **Solenoids and Inductive Loads:** Handling the high-energy startup spikes associated with electromagnetic coils. 4. **Lighting Loads:** Used in specialized industrial lighting ballast protection. --- ### 4. Comparison with Standard FNQ While both are "Midget" sized fuses, there is a distinct difference: * **FNQ:** Supplemental protection, no rejection tip, lower interrupting rating. * **FNQ-R:** Branch circuit protection, includes rejection tip, high interrupting rating (200kA).