The **LPS-RK-45SP** is a high-performance, dual-element, time-delay power fuse belonging to the **Low-Peak™** series manufactured by Bussmann (Eaton). It is categorized under **Class RK1**. --- ## 1. Technical Specifications The following table outlines the core electrical characteristics of the LPS-RK-45SP: | Feature | Specification | | :--- | :--- | | **Current Rating** | 45 Amperes | | **Voltage Rating (AC)** | 600 Vac | | **Voltage Rating (DC)** | 300 Vdc | | **Interrupting Rating (AC)** | 300,000 A (RMS Symmetrical) | | **Interrupting Rating (DC)** | 100,000 A | | **Class** | RK1 | | **Fuse Type** | Dual-Element, Time-Delay | --- ## 2. Key Electronic Features ### A. Dual-Element Design Unlike standard fuses, the LPS-RK-45SP contains two distinct components: 1. **Thermal Cutout:** Handles long-term overloads. It allows temporary surges (like motor startups) to pass without blowing. 2. **Short-Circuit Element:** A fast-acting component that triggers immediately during high-magnitude short circuits to prevent equipment damage. ### B. Current Limitation As a **Class RK1** fuse, it is highly current-limiting. In the event of a massive short circuit, the fuse reacts so quickly that it prevents the current from reaching its full peak. This significantly reduces the "arc flash" energy and the mechanical stress on downstream electronic components. ### C. Time-Delay Property The "SP" in the part number often refers to its specialized performance in handling inrush currents. It provides a minimum of **10 seconds delay at 500% of the rated current**, making it ideal for circuits with motors or transformers that have high momentary power draws. --- ## 3. Physical & Material Composition * **Body Material:** Typically high-grade melamine or fiberglass tube for superior arc-quenching and structural integrity. * **End Caps:** Heavy-duty brass or copper alloy with plating to ensure low contact resistance and prevent oxidation. * **Size:** Standard 600V, 31-60A frame size (Length: 5.5 inches; Diameter: 1.06 inches). --- ## 4. Typical Applications * **Branch Circuit Protection:** Used in industrial control panels. * **Motor Protection:** Specifically designed for motor circuits where Type 2 "No Damage" protection is required. * **Inductive Loads:** Transformers and solenoids that experience high initial magnetization currents. * **Mains Disconnects:** Serving as the primary safety link for power distribution blocks.