Limit Switch | 40-Piece Box Set | 5A 250VAC KW12 Snap Action Lever

This is a box of 40 mini limit switches. Each one has a roller arc lever. These KW12-style switches are basic parts for sensing physical contact in electronics. The snap-action design makes a clean and quick change between on and off. You'll hear an audible click. Features and Benefits - Snap-Action Mechanism - The switch changes state firmly once the activation point is met. This stops slow or partial connections. - 3-Pin Configuration - Each micro switch has Common, Normally Open (NO), and Normally Closed (NC) contacts. This offers wiring choices. - Roller Arc Lever - The lever gives a good surface for activation. The roller helps lower friction from moving parts. - 5A 250VAC Rating - They are rated to manage common electrical loads. They work well for many control circuits. Applications - DIY Electronics - Good for sensing when a lid is shut, a lever is pulled, or an object is in place. - Arcade Cabinet Builds - Use them for joystick direction inputs. Or use them as the internal switch for arcade buttons. - Automation Equipment - A simple and effective electrical limit switch. Use it for robotics and custom automation projects. Step 1: Address the Root Cause First Before attempting to reset a limit switch, it is crucial to identify and rectify the underlying issue that triggered it. A limit switch, such as the KW12 mini limit switch in this 40-piece box set, acts as a safety device. It prevents machinery from exceeding its operational limits, often by detecting an over-temperature or over-pressure condition. For instance, on a furnace, a common cause for a limit switch tripping is a clogged air filter restricting airflow, leading to overheating. Always address the root cause to prevent immediate re-tripping and potential damage. Step 2: How to Reset the Switch Resetting a limit switch depends on its design. The KW12 snap action lever switch offers a robust and quick response. Generally, there are two primary methods for resetting these safety devices once the root cause has been resolved. Understanding the type of limit switch, whether it is an automatic or manual reset, is key to successful operation. This 40-piece set provides versatility for various applications requiring a 5A 250VAC switch. Method A: Automatic / Soft Reset (Most Common) Many limit switches, including those with a snap action mechanism, are designed for automatic reset once the abnormal condition is cleared. For example, if a furnace limit switch tripped due to overheating (e.g., reaching 115°F), it will typically reset itself once the temperature drops back to a safe level, such as below 100°F. Ensure the power to the circuit controlled by the switch is maintained for an automatic reset. There is no physical action required on the switch itself. Method B: Manual Reset Switch Some limit switches, especially those for critical safety applications, require a manual reset. This means a physical action, often pressing a small button or toggling a lever, is needed to re-engage the contacts. This ensures an operator has acknowledged the fault condition. If your application uses a manual reset limit switch, locate the reset mechanism on the switch body. The 2 or 3 pins on the KW12 switch provide options for various circuit configurations, including those with manual reset capabilities. When to Call a Professional If a limit switch repeatedly trips despite addressing potential root causes, or if you are unsure about the nature of the fault, it is essential to call a qualified professional. Tampering with electrical components, particularly those operating at 250V AC, can be hazardous. A professional can diagnose complex issues, such as a faulty controller or persistent mechanical problems that the bump sensor or lever mechanism of the limit switch is detecting. Prioritise safety and avoid unnecessary risks.