The **FNQ-R-3/4-R1** is a high-performance, time-delay supplemental fuse part of the **Limitron™** series manufactured by Eaton (Bussmann Division). This specific model is designed primarily for industrial control circuits and motor branch-circuit protection. --- ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Current Rating** | 0.75 Amps (3/4 A) | | **Voltage Rating (AC)** | 600 Vac | | **Interrupting Rating** | 200,000 Amps RMS Symmetrical | | **Fuse Class** | Class CC | | **Response Time** | Time-Delay (Slow Blow) | | **Dimensions** | 13/32" x 1-1/2" (10.3 x 38.1 mm) | --- ### 2. Functional Characteristics #### High Rejection Feature (The "-R" Suffix) The "R" in the part number signifies a **rejection tip**. This is a physical design feature on the end cap that prevents lower-rated fuses (like standard midget fuses) from being inserted into a Class CC fuse holder. This ensures that the circuit remains protected by a fuse capable of handling high fault currents. #### Time-Delay Properties Unlike "Fast-Acting" fuses, this fuse is engineered to handle temporary **inrush currents**. This makes it ideal for: * Small control transformers. * Solenoids. * Inductive loads that experience a brief surge upon startup. #### Current Limitation The FNQ-R is a **current-limiting fuse**. In the event of a massive short circuit, it reacts within a fraction of a cycle to "cut off" the current before it reaches its full destructive peak, protecting sensitive downstream components. --- ### 3. Physical Construction * **Body Material:** Melamine (fiberglass) tube for high arc resistance and durability. * **End Caps:** Nickel-plated brass for high conductivity and corrosion resistance. * **Mounting:** Fits into standard Class CC fuse blocks or rail-mount holders. --- ### 4. Comparison: FNQ-R vs. Standard FNQ | Feature | FNQ (Midget) | FNQ-R (Class CC) | | :--- | :--- | :--- | | **Rejection Tip** | No | Yes | | **Interrupting Rating** | 10,000 Amps | 200,000 Amps | | **Safety Level** | Supplemental | Branch Circuit Protection | ---