Limit Switch | Roller Lever Arm Actuator | SPDT NO/NC Contacts

This micro roller lever switch is a small snap-action switch. It detects when a part moves. The KW12-3 switch uses a small roller to make contact. It sends a signal when an object reaches a certain point. Features and Benefits - Roller lever actuator - The wheel lowers friction and side-loading. This works well for parts that slide into place. - SPDT 1NO 1NC contacts - The 3-pin micro switch roller design gives you both Normally Open and Normally Closed circuits. This offers wiring options. - Tactile snap-action mechanism - It sends a quick, clear electrical signal. You hear a click, confirming it activated. - 5A 250VAC electrical rating - It can power small motors, solenoids, and lights. This covers many common devices. Applications - An endstop for a 3D printer or CNC machine. It homes the axes accurately. - A door interlock switch in a microwave oven. It stops the unit from running when open. - Part detection in automated equipment. It confirms a component is in place before the next step. Step 1: Address the Root Cause First A limit switch, such as this Micro Roller Lever Arm type, acts as a bump sensor within control systems. Before attempting to reset a limit switch, it is crucial to identify why it tripped. Common issues include obstructions preventing the roller lever arm from actuating correctly, or excessive temperature in systems like a furnace, causing a thermal limit switch to open. For this product, featuring Normally Open and Normally Close contacts, ensure the mechanical actuation path is clear and that operating conditions are within the system's specified parameters to prevent immediate re-tripping. Step 2: How to Reset the Switch How to reset a limit switch on a furnace or any other control system depends on the type of switch and the system design. This specific product is a standard limit switch with SPDT NO/NC contacts, meaning it does not inherently possess a reset mechanism. Resetting typically involves addressing the condition that caused the switch to trip, allowing it to return to its normal state. Understanding if the system expects a Normally Open or Normally Close state is key to proper system function after addressing the root cause. Method A: Automatic / Soft Reset (Most Common) Many control systems are designed for an automatic or 'soft' reset of a limit switch once the triggering condition is removed. For example, if a furnace limit switch trips due to overheating (e.g., exceeding 115°f), it will often reset itself once the temperature drops back to a safe level (e.g., below 100°f). For this Micro Roller Lever Arm switch, an automatic reset occurs when the physical obstruction or force on the roller lever arm is removed, allowing the switch to return to its default Normally Open or Normally Close state, depending on the wiring. Method B: Manual Reset Switch This particular limit switch, a Micro Roller Lever Arm type with SPDT NO/NC contacts, does not feature a built-in manual reset button. Some limit switches, especially those designed for safety-critical applications, incorporate a manual reset feature, requiring a deliberate action, such as pressing a button, to re-engage the circuit. If your control system requires a manual reset, and you are using this product as a component, the manual reset functionality would need to be incorporated into the wider control system, perhaps via a separate toggle switch or control panel. When to Call a Professional If a limit switch consistently trips, even after addressing apparent causes and attempting resets, it is advisable to call a professional. This applies particularly to critical systems like furnaces, where repeated tripping of a limit switch could indicate a more serious underlying fault, such as a malfunctioning blower motor or a blocked flue. While this product provides reliable Normally Open and Normally Close contacts, persistent issues with its actuation or the system it controls suggest a need for expert diagnosis to prevent potential damage or unsafe operating conditions.