The **FNQ-R-3** is a high-performance industrial fuse part of the **Limitron™** series manufactured by **Bussmann (Eaton)**. It is a time-delay, Class CC rejection-type fuse designed specifically for the protection of control transformers and circuits with high inrush currents. --- ### ## Technical Specifications The following table outlines the core electronic and physical properties of the FNQ-R-3: | Feature | Specification | | :--- | :--- | | **Current Rating** | 3 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 | | **Dimensions** | 13/32" x 1-1/2" (10.3 x 38.1 mm) | --- ### ## Key Electronic Characteristics #### 1. Time-Delay Functionality The FNQ-R-3 is engineered with a "time-delay" characteristic. This allows the fuse to withstand temporary surge currents (inrush) often seen when starting motors or energizing transformers, preventing "nuisance blowing." However, it will still open quickly if a sustained overcurrent or short-circuit occurs. #### 2. Rejection Feature As a **Class CC** fuse, it features a physical "rejection tip" on one of the endcaps. This ensures that: * It can only be inserted into a Class CC fuse holder. * Lower-rated fuses (like standard midget fuses) cannot be accidentally placed into the circuit, maintaining the safety integrity of the system. #### 3. High Interrupting Capacity With a rating of **200kA**, this fuse can safely clear very high fault currents without exploding or damaging the surrounding equipment. This makes it ideal for use in "Current Limiting" applications. --- ### ## Common Applications * **Control Transformers:** Protecting the primary side of industrial control transformers. * **Solenoids:** Handling the high initial current required to engage magnetic coils. * **Motor Control Circuits:** Providing branch circuit protection where space is limited. * **Lighting Ballasts:** Protecting sensitive electronic ballasts from power surges. --- ### ## Comparison: FNQ-R vs. Standard FNQ It is important not to confuse the **FNQ-R** with the standard **FNQ** series: | Feature | FNQ (Standard) | FNQ-R (Limitron) | | :--- | :--- | :--- | | **Class** | Midget | Class CC | | **Rejection Tip** | No | Yes | | **Interrupting Rating** | 10kA | 200kA | | **Primary Use** | General Purpose | Transformer Protection |