The **KWN-R-30** is a specific model of a **Class RK1, current-limiting, time-delay fuse**. It is part of the "Limitron" series manufactured by Eaton (Bussmann Division). These fuses are critical for protecting electrical circuits from overcurrent and short-circuit conditions. --- ### Technical Specifications The following table outlines the primary electrical characteristics of the KWN-R-30: | Feature | Specification | |:---|:---| | **Amperage Rating** | 30 Amps | | **Voltage Rating** | 250 VAC (Volts AC) | | **Interrupting Rating** | 200,000 Amps RMS Symmetrical | | **Fuse Class** | Class RK1 | | **Response Type** | Time-Delay / Slow-Blow | | **Body Material** | Melamine/Glass-Fiber tube with metal end caps | --- ### Key Components and Design #### 1. Time-Delay Mechanism Unlike "Fast-Acting" fuses, the KWN-R-30 is designed with a dual-element or time-delay feature. This allows the fuse to withstand temporary **inrush currents** (common in motors or transformers) without blowing, while still providing high-speed protection against massive short circuits. #### 2. RK1 Current Limitation The "RK1" designation is a safety standard. RK1 fuses are highly current-limiting, meaning they react so fast during a major fault that they stop the current from reaching its maximum peak. This prevents damage to sensitive downstream electronic components like VFDs (Variable Frequency Drives) or controllers. #### 3. Rejection Feature The "R" in the model name indicates a **rejection tip**. The physical design of the end caps prevents someone from accidentally replacing this high-performance fuse with a lower-rated Class H or K fuse, ensuring the safety integrity of the system remains intact. --- ### Common Applications * **Motor Branch Circuits:** Protection for small to medium-sized motors where startup surges occur. * **Inductive Loads:** Transformers and solenoids. * **Service Entrance Equipment:** Used in main disconnects for residential or light commercial buildings. * **Panelboards:** Protecting branch circuits from high-fault current levels. --- ### Comparison: RK1 vs. RK5 While both fit in the same holders, the KWN-R-30 (RK1) provides superior protection compared to a standard RK5 fuse: | Feature | Class RK1 (KWN-R) | Class RK5 (FRN-R) | |:---|:---|:---| | **Current Limitation** | Extremely High | Moderate | | **Arc Flash Hazard** | Lower | Higher | | **Price** | More Expensive | Less Expensive |