The Differences Between Magnetic Gear Tooth Sensors
Gear tooth sensors are used to measure and detect the status of specific gears within a gearbox. Most sensors operate using the principles of magnetism. Magnetic sensors work on the premise that an electric voltage can be induced by changing a magnetic field. As a gear tooth rotates, the magnetic field around the sensor changes, which induces an alternating current voltage. The speed at which the gear tooth spins determines the frequency of the voltage and creates a measurable output.
Some magnetic sensors have an internal magnet that detects other magnetic material such as iron. There are also sensors with external magnets that detect a magnetic field around a coil. Hall-effect sensors use an external magnetic field to induce a voltage that is directly proportional to the magnetic field and varies as the magnetic field changes. Hall-effect sensors can produce analog or digital outputs. Magnetoresistive sensors also use an external magnet, but the measurable output is produced by increased resistance in the electrical current. A variety of magnetic sensors and Hall effect sensors are available from Sensor Solutions.
Most other designs are variations of Hall-effect and magnetoresistive sensors. For example, angular position sensors measure the angle of the magnetic field to determine the position of a gear. Speed sensors measure the frequency at which magnetic gears pass the sensor in order to determine the gear speed. Speed switches operate similarly but are designed to detect zero speed or a defined speed threshold. Speed and direction sensors have two separate sensing elements to measure the speed of a gear and its direction of rotation by identifying which sensing element the gear passes first. Proximity sensors detect the distance between the sensor and the assigned gear by sending out a signal and receiving feedback from the gear.
Magnetic sensors are the most common type of gear tooth sensors and consist of a variety of designs depending on the desired function. Consider the function, purpose and output type when selecting the right sensor for your application.