The **FRS-R-3/10** is a specific type of industrial-grade fuse. It belongs to the **Fusetron™** series manufactured by Eaton (Bussmann Division). This component is a heavy-duty, dual-element, time-delay fuse designed for circuit protection. ### Technical Specifications | Feature | Specification | | :--- | :--- | | **Model Number** | FRS-R-3/10 | | **Amperage Rating** | 0.3 Amps (3/10 A) | | **Voltage Rating (AC)** | 600 Vac | | **Voltage Rating (DC)** | 300 Vdc | | **Interrupting Rating** | 200,000 Amps RMS Symmetrical | | **Class** | Class RK5 | | **Fuse Body Material** | Fiberglass Tube | --- ### Key Electronic Characteristics #### 1. Dual-Element Design The FRS-R-3/10 contains two distinct elements that provide "smart" protection: * **Thermal Element:** Handles low-level overloads. It provides a **Time-Delay** feature, allowing temporary surges (like motor startups) to pass without blowing the fuse. * **Instantaneous Element:** A fast-acting magnetic mechanism that clears high-level short circuits immediately to prevent fire or equipment damage. #### 2. Rejection Feature (The "R" in FRS-R) The "R" signifies that this is a **Class RK5** rejection fuse. The end caps are physically keyed to prevent a lower-rated fuse (like a Class K5) from being installed into a Class R fuse clip. This ensures that the circuit remains protected by a fuse capable of handling 200,000 Amps of interrupting current. #### 3. Current Limitation Despite being a time-delay fuse, it is **current-limiting**. In the event of a massive short circuit, the fuse will blow fast enough to prevent the current from reaching its full destructive peak, protecting downstream components like contactors and breakers. --- ### Common Applications * **Motor Protection:** Used in circuits where small motors might have a momentary "inrush" current that is higher than 0.3A. * **Control Transformers:** Protecting the primary side of small industrial transformers. * **Solenoids:** Often used in industrial automation to protect low-current solenoid valves. * **General Feeder Circuits:** Used in mains panels where high voltage (600V) and high fault current capacity are required. --- ### Comparison: FRS-R (600V) vs. FRN-R (250V) It is important to note that the **FRS** series is rated for **600V**, whereas its sister series, the **FRN**, is only rated for **250V**. You can use an FRS-R-3/10 in a 250V circuit, but you cannot use an FRN-R in a 600V circuit.