The **LPS-RK-50SP** is a high-performance, current-limiting, dual-element time-delay fuse. It belongs to the **Low-Peak™** series manufactured by Bussmann (Eaton). This specific model is rated for 50 Amps and is widely used in industrial and commercial electrical systems to protect sensitive electronics and motors. --- ### Technical Specifications | Feature | Specification | |:---|:---| | **Part Number** | LPS-RK-50SP | | **Ampere Rating** | 50 Amps | | **Voltage Rating (AC)** | 600 Vac | | **Voltage Rating (DC)** | 300 Vdc | | **Interrupting Rating** | 300kA RMS Sym. (AC) / 100kA (DC) | | **Fuse Class** | Class RK1 | | **Element Type** | Dual-Element (Time-Delay) | | **Material** | Melamine tube with brass end caps | --- ### Key Electronic Characteristics #### 1. Dual-Element Design The "Dual-Element" construction consists of two distinct components working in tandem: * **Thermal Cutout:** Handles low-level overloads. It has a time-delay feature that allows temporary surges (like motor startups) to pass without blowing the fuse. * **Short-Circuit Element:** A fast-acting component that opens almost instantaneously when it detects high-level short circuits. #### 2. Current Limitation (Class RK1) As a Class RK1 fuse, the LPS-RK-50SP is highly current-limiting. In the event of a massive short circuit, it reacts faster than a standard circuit breaker, "choking" the current before it reaches its full destructive peak. This protects downstream electronic components from thermal and magnetic stress. #### 3. High Interrupting Rating With a **300,000 Amp (300kA)** interrupting rating, this fuse can safely extinguish very high-energy arcs. This makes it suitable for locations with high available fault current, ensuring the fuse housing does not rupture during a failure. --- ### Common Applications * **Motor Branch Circuits:** The time-delay allows for the high in-rush current required to start motors. * **Inductive Loads:** Used for transformers and solenoids where temporary spikes are normal. * **Main Service Switches:** Provides superior protection for the entire electrical panel due to its RK1 coordination. * **Panelboards:** Used where space is at a premium and high-level protection is required. --- ### Advantages of the "SP" (Super-Lag) Series The **SP** designation indicates the "Low-Peak" performance level, which offers: 1. **Coordination:** Easier to "selectively coordinate" with other fuses to ensure only the fuse closest to the fault opens. 2. **Energy Efficiency:** Lower watts loss compared to older fuse designs, reducing heat buildup in the enclosure. 3. **Versatility:** Since it handles both AC and DC, it can be used in solar inverters and battery storage systems.