A basic inductive speed sensor detects the speed of rotating equipment using the principle of electromagnetic induction. The sensor consists of a coil of wire wound around a magnetic core. When the target rotating equipment, such as a gear or a toothed wheel, moves in proximity to the sensor, it induces changes in the magnetic field around the coil, which generates an electrical signal.
Here's a step-by-step explanation of how it works:
Magnetic Field Generation: When the target rotating equipment (usually made of ferromagnetic material) moves close to the inductive speed sensor, it disturbs the magnetic field generated by the coil and magnetic core.
Flux Changes: As the target moves closer to the sensor, the magnetic flux passing through the coil changes. This change in magnetic flux induces an electrical voltage across the coil.
Induced Voltage: The induced voltage is proportional to the speed at which the target rotates. The faster the target moves, the higher the frequency and amplitude of the induced voltage.
Signal Processing: The induced voltage is an AC signal that needs to be processed. It goes through signal conditioning and amplification to make it suitable for further use and to improve its signal-to-noise ratio.
Speed Calculation: After the signal is processed, it can be fed into a speed measurement system, such as a frequency counter or microcontroller. By counting the number of voltage cycles per unit of time, the speed of the rotating equipment can be calculated.
The inductive speed sensor can be a non-contact type, meaning it does not make physical contact with the rotating equipment. This feature makes it suitable for applications where physical wear and tear on the sensor need to be minimized.
This type of speed sensor is commonly used in various industries for monitoring and controlling the speed of rotating machinery, such as motors, engines, turbines, and conveyor belts. Inductive speed sensors are relatively simple, robust, and reliable, making them widely used in a wide range of industrial applications.