The **KTK-R-2-1/2** is a high-performance industrial fuse manufactured by Bussmann (Eaton). It belongs to the **Limitron™ KTK-R Series** and is specifically designed for branch circuit protection in electrical systems. ### Technical Specifications | Parameter | Specification | | :--- | :--- | | **Manufacturer** | Bussmann (Eaton) | | **Part Number** | KTK-R-2-1/2 | | **Ampere Rating** | 2.5 Amps (2-1/2A) | | **Voltage Rating (AC)** | 600 Vac | | **Interrupting Rating** | 200,000 Amps RMS Symmetrical | | **Fuse Class** | Class CC | | **Fuse Type** | Fast-Acting | | **Body Material** | Melamine | | **Dimensions** | 13/32" x 1-1/2" (10.3 x 38.1 mm) | --- ### Key Features and Electronic Design #### 1. Class CC Characteristics The "R" in the part number signifies that it is a **Rejection Style** fuse. This means it has a specialized physical tip on one end that prevents the installation of fuses with lower voltage or interrupting ratings into a Class CC fuse holder. This is a critical safety feature for high-voltage industrial panels. #### 2. Fast-Acting Response Unlike "Time-Delay" fuses, the KTK-R series is **Fast-Acting**. It is designed to open almost instantly when it detects an overcurrent or short-circuit condition. This makes it ideal for protecting sensitive electronic components that cannot withstand prolonged surges. #### 3. High Interrupting Rating With a **200kA interrupting rating**, this fuse can safely handle massive short-circuit currents without exploding or arcing, which is vital for meeting UL (Underwriters Laboratories) standards for industrial control panels. --- ### Common Applications The KTK-R-2-1/2 is typically found in the following environments: * **Control Circuits:** Protecting control transformers and small motors. * **Lighting Circuits:** High-voltage lighting ballasts. * **HVAC Systems:** Used in specialized control panels for heating and cooling. * **General Purpose:** Any branch circuit requiring 600V protection and a small physical footprint. --- ### Comparison with Similar Fuses | Feature | KTK-R (Rejection) | KTK (Standard) | FNQ-R (Time-Delay) | | :--- | :--- | :--- | :--- | | **Rejection Tip** | Yes | No | Yes | | **Speed** | Fast-Acting | Fast-Acting | Time-Delay | | **Primary Use** | Branch Protection | Supplemental | Motor Circuits |