The **LPS-RK-20SP** is a high-performance, current-limiting power fuse belonging to the **Low-Peak™** series manufactured by Bussmann (Eaton). It is widely used in industrial and commercial electrical systems to protect sensitive electronic components and branch circuits. --- ### 1. Technical Specifications Below are the primary electronic and physical characteristics of the LPS-RK-20SP: | Feature | Specification | | :--- | :--- | | **Model Number** | LPS-RK-20SP | | **Amperage Rating** | 20 Amps | | **Voltage Rating (AC)** | 600 Vac | | **Voltage Rating (DC)** | 300 Vdc | | **Interrupting Rating (AC)** | 300,000 Amps RMS Symmetrical | | **Interrupting Rating (DC)** | 100,000 Amps | | **Class** | RK1 | | **Fuse Type** | Dual-Element, Time-Delay | --- ### 2. Key Electronic Features #### A. Dual-Element Design Unlike standard single-element fuses, the LPS-RK-20SP contains two distinct components: * **Thermal Element:** Handles low-level overloads. It provides a "time-delay," allowing temporary surges (like motor startups) to pass without blowing the fuse. * **Short-Circuit Element:** A high-speed element that reacts instantly to massive current spikes, preventing catastrophic damage to the circuit. #### B. Current Limitation As a **Class RK1** fuse, it is highly current-limiting. In the event of a short circuit, the fuse clears the fault so quickly that the actual peak current never reaches its full potential. This significantly reduces the **Arc Flash** hazard and protects downstream components like controllers and breakers. #### C. Indication System The "SP" suffix often denotes the **SmartSpot™** or visual indication feature (depending on the specific production line). This allows maintenance personnel to identify a blown fuse immediately by looking at the darkened indicator window on the fuse body. --- ### 3. Common Applications The LPS-RK-20SP is typically integrated into the following electronic and power environments: 1. **Motor Branch Circuits:** High "in-rush" current capability makes it ideal for protecting motors. 2. **Transformer Protection:** Prevents damage from primary side surges. 3. **Panelboards:** Used in safety switches to provide superior short-circuit protection compared to standard breakers. 4. **Inductive Loads:** Used where solenoids or heavy relays are present. --- ### 4. Direct Comparison: RK1 vs. RK5 | Feature | Class RK1 (LPS-RK) | Class RK5 (FRN-R/FRS-R) | | :--- | :--- | :--- | | **Current Limitation** | Extremely High | Moderate | | **Protection Level** | Superior for Electronics | Standard for General Purpose | | **Interchangeability** | Fits same holders | Fits same holders |