The **LK1-3-R** is a specific model of a **Keypad/Key Switch** commonly used in industrial control systems, security panels, or specialized vending machines. It is typically manufactured by brands like *Interlock* or *Schurter*. --- ### 1. Technical Specifications The "LK" series usually refers to a keyswitch mechanism designed for electrical isolation and mode selection. | Component Property | Typical Specification | | :--- | :--- | | **Contact Configuration** | Single Pole Single Throw (SPST) or DPST | | **Switching Voltage** | 125V AC / 250V AC | | **Current Rating** | 1A to 4A (depending on load type) | | **Termination** | Solder tabs or Screw terminals | | **Material** | Zinc Alloy housing with Chrome plating | | **Key Type** | Tubular or Flat key (Model dependent) | --- ### 2. Key Features and Functions * **Security Lockout:** Unlike a standard push button, the LK1-3-R requires a physical key to change the state of the circuit, preventing unauthorized operation. * **Rotational Positions:** * **90° or 180° indexing:** Usually features two positions (On/Off). * **Key Retention:** The "R" in the suffix often indicates **Key Removable** in certain positions (e.g., removable in both On and Off, or only in Off). * **Rugged Construction:** Designed for high-cycle life (often rated for 10,000+ operations) and resistance to tampering. --- ### 3. Pinout and Connection While specific wiring depends on the internal contact block, the standard 3-pin or 2-pin layout follows this logic: ```markdown Pin 1 (COM): Common Input Power Pin 2 (NO): Normally Open (Connects when key is turned) Pin 3 (NC): Normally Closed (Disconnects when key is turned - if applicable) ``` --- ### 4. Common Applications 1. **Industrial Machinery:** Used as an "Emergency Bypass" or "Maintenance Mode" switch. 2. **Elevator Controls:** Restricting access to certain floors or service menus. 3. **Alarm Systems:** Arming/Disarming a security partition. 4. **Computer Servers:** Hard-locking the chassis or power state.