How does the limit switch work?

The limiter switch is used to automatically detect or sense the presence of an object, or to monitor and indicate whether the movement limit of the object is exceeded. As its title implies, the limit switch's original use was to define the limit or endpoint that an object could pass through before aborting. It is at this point that the switch engages to manipulate the travel constraints.

How does the limiter switch work?

A standard limit switch used in industrial applications is an electromechanical device consisting of a mechanical actuator connected to a series of electrical contacts. When an object (sometimes called a target) creates a physical touch with the actuator, the movement of the actuator plunger causes the electrical contact within the switch to close (for normally open circuits) or break (for normally closed circuits) the electrical connection. Limit switches use the mechanical movement of the actuator plunger to control or change the condition of the electrical switch. Similar devices, such as inductive or capacitive proximity sensors or photoelectric sensors, can achieve the same results without touching the object. Therefore, in contrast to these other types of proximity sensing devices, the limit switch is a touch sensor. Most limit switches are mechanical in operation and contain heavy-duty contacts that can switch higher currents than backup proximity sensors.

The use and operation of the limit switch:

In most cases, the limit switch begins operation when the moving machine or moving part of the machine touches the actuator or joystick that activates the switch. The limit switch then regulates the circuitry that controls the machine and its moving parts. These switches can be used as guiding devices for the magnetic starter control circuit, allowing them to start, stop, slow down or accelerate motor functions. The limit switch can be installed in the machine as a control surface for standardized operation, or as an emergency device to prevent mechanical failure. Most switches are either hold touch or instantaneous touch.