A basic inductive speed sensor, also known as an inductive proximity sensor, is a type of non-contact sensor commonly used to detect the speed of rotating equipment. It works based on the principle of electromagnetic induction. The sensor generates a magnetic field and detects changes in the field caused by the presence of a metal target, such as a gear tooth or a metal collar attached to a rotating shaft. Here's how it works:
Magnetic field generation: The inductive speed sensor has an internal coil that is supplied with an electrical current, generating a magnetic field around the sensor.
Metal target detection: As the rotating equipment passes near the sensor, the presence of a metal target (such as a gear tooth) causes a disturbance in the magnetic field.
Inductive effect: When the metal target enters the magnetic field, it induces eddy currents in the metal. These eddy currents create a secondary magnetic field that opposes the primary magnetic field of the sensor.
Signal generation: The inductive speed sensor detects this change in the magnetic field and converts it into an electrical signal. The frequency of the signal corresponds to the speed of the rotating equipment.
Signal processing: The electrical signal is then processed by a control system or a monitoring device to calculate the speed of the rotating equipment.
The inductive speed sensor is widely used in various applications, such as monitoring the speed of motors, engines, conveyor belts, and other rotating machinery. It offers advantages like non-contact operation, high reliability, and suitability for harsh environments where dust, dirt, and moisture may be present.
Keep in mind that while inductive sensors are useful for detecting the speed of rotating metal targets, they may not be suitable for detecting non-metallic materials or materials that are not conductive. In those cases, other types of sensors, such as optical encoders or capacitive sensors, might be used.