The **LPS-RK-1SP** is a high-performance, current-limiting, dual-element time-delay fuse. It belongs to the **Low-Peak™** series manufactured by Bussmann (Eaton). This specific fuse is designed for heavy-duty industrial applications requiring superior protection against short circuits and overloads. ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Series** | Low-Peak™ (LPS-RK) | | **Current Rating** | 1 Amp | | **Voltage Rating (AC)** | 600 Vac | | **Voltage Rating (DC)** | 300 Vdc | | **Interrupting Rating** | 300kA RMS Sym. (AC) / 100kA (DC) | | **Fuse Class** | Class RK1 | | **Construction** | Dual-Element, Time-Delay | --- ### 2. Electronic & Functional Features #### A. Dual-Element Design The "SP" in the name stands for **Special Purpose** (often used for the Silver-Plated/Indication variants). Internally, it contains two distinct components: 1. **Thermal Element:** Handles low-level overloads. It has a time-delay feature that allows for temporary surges (like motor startups) without blowing. 2. **Magnetic Short-Circuit Element:** Acts instantly when it detects high-level short circuits to protect sensitive downstream electronic components. #### B. Current Limitation As a **Class RK1** fuse, it is highly current-limiting. In the event of a massive fault, the fuse reacts so quickly that it prevents the current from reaching its full peak magnitude. This reduces the "let-through energy," protecting equipment from thermal and mechanical stress. #### C. Time-Delay Characteristics * **Minimum Delay:** It can hold 500% of its rated current (5 Amps in this case) for a minimum of 10 seconds. * **Benefit:** Prevents "nuisance blowing" caused by the inrush current of small transformers or motors. --- ### 3. Physical Construction * **Body Material:** High-grade fiberglass or melamine tube for high arc resistance. * **End Caps:** Typically features blade or ferrule terminals (the 1A version uses ferrule/cylindrical caps). * **Plating:** The contacts are often silver-plated to ensure low resistance and prevent oxidation over long periods of service. --- ### 4. Typical Applications * **Branch Circuit Protection:** Used in electrical panels to protect individual circuits. * **Motor Protection:** Ideal for small motors where high inrush current is present. * **Control Transformers:** Protects the primary side of transformers. * **Inductive Loads:** Any circuit with solenoids or coils that creates temporary current spikes.