The **FNQ-R-4-1/2** is a high-performance, time-delay fuse belonging to the **Limitron™ CC Series** produced by Bussmann (Eaton). It is specifically engineered to handle the high inrush currents typical of control transformers and small motor circuits. ### 1. Technical Specifications The "4-1/2" in the part number indicates the current rating of 4.5 Amperes. | Parameter | Specification | | :--- | :--- | | **Brand** | Bussmann (Eaton) | | **Series** | FNQ-R (Class CC) | | **Current Rating** | 4.5 Amps | | **Voltage Rating (AC)** | 600 Vac | | **Interrupting Rating** | 200,000 Amps (RMS Symmetrical) | | **Fuse Type** | Time-Delay (Slow Blow) | | **Body Material** | Melamine | | **Termination Style** | Cartridge (Ferrule) | --- ### 2. Key Physical & Design Features * **Rejection Feature:** As a **Class CC** fuse, it features a unique physical rejection tip on the bottom cap. This ensures it can only be inserted into a Class CC fuse holder, preventing the accidental installation of a lower-rated fuse (like a Midget fuse) in a critical circuit. * **Time-Delay Characteristic:** Unlike fast-acting fuses, the FNQ-R-4-1/2 is designed to ignore temporary current spikes (inrush) that occur when a device starts up, while still providing protection against sustained overloads and short circuits. * **Melamine Tube:** The body is made from high-grade melamine, which provides excellent arc suppression and heat resistance. --- ### 3. Common Applications This specific fuse is most commonly found in industrial control panels. * **Control Transformers:** It is specifically designed to provide "Type 2" protection for control transformers, handling the inductive surges without nuisance tripping. * **Solenoids:** Protects coils from burning out during stalled conditions. * **Small Motors:** Used for branch circuit protection in fractional horsepower motors. --- ### 4. Cross-Reference & Alternatives If you are looking for equivalents from other major manufacturers: | Manufacturer | Equivalent Series | | :--- | :--- | | **Littelfuse** | KLDR Series (KLDR-4.5) | | **Mersen (Ferraz Shawmut)** | ATDR Series (ATDR4-1/2) | ---