## Technical Overview: FRS-R-35 Fuse The **FRS-R-35** is a high-performance industrial fuse manufactured by **Eaton (Bussmann Series)**. It belongs to the **Fusetron™** family and is categorized as a **Class RK5** dual-element, time-delay fuse. ### 1. Core Specifications | Feature | Specification | | :--- | :--- | | **Amperage Rating** | 35 Amps | | **Voltage Rating (AC)** | 600 Vac | | **Voltage Rating (DC)** | 300 Vdc | | **Interrupting Rating (AC)** | 200,000 Amps RMS Symmetrical | | **Interrupting Rating (DC)** | 20,000 Amps | | **Class** | RK5 | | **Type** | Dual-Element, Time-Delay | --- ### 2. Electronic Components and Design The FRS-R-35 is not a simple wire fuse; it utilizes a **dual-element design** to handle different types of electrical faults: 1. **Thermal Element (Time-Delay):** * Designed to handle low-level overloads (e.g., motor startups or temporary surges). * It typically allows 500% of the rated current for at least 10 seconds. * This prevents "nuisance tripping" when machinery first powers on. 2. **Magnetic/Instantaneous Element:** * Composed of a notched copper link designed to react instantly to high-level short circuits. * This component clears the fault in milliseconds to protect downstream electronics and prevent arc flashes. --- ### 3. Key Electronic Features * **Current Limitation:** As a Class RK5 fuse, it significantly limits the peak let-through current during a fault. This reduces the mechanical and thermal stress on the rest of the circuit's components. * **Rejection Feature:** The "R" in FRS-R indicates a rejection tip. This physical design prevents the installation of fuses with lower voltage or interrupting ratings into the same fuse holder, ensuring safety compliance. * **Dual-Voltage Compatibility:** While optimized for 600V AC industrial power, it is also rated for 300V DC, making it versatile for heavy-duty DC motor controls or UPS systems. --- ### 4. Primary Applications Because of its time-delay characteristics, the FRS-R-35 is primarily used for: * **Motor Branch Circuits:** Protection against motor burnout from overloads or single-phasing. * **Transformers:** Handling the high inrush current when a transformer is first energized. * **General Purpose Solenoids:** Protecting inductive loads that have high initial current draws. ---