A basic inductive speed sensor, also known as an inductive proximity sensor or an inductive proximity switch, detects the speed of rotating equipment by using electromagnetic principles. These sensors are commonly used in industrial applications for monitoring and controlling rotational speed.
Here's how a basic inductive speed sensor works:
Operating Principle: An inductive speed sensor operates on the principle of electromagnetic induction. When a metallic target (such as a gear, shaft, or rotating equipment) moves in front of the sensor, it induces eddy currents in the metal, creating a magnetic field around the target.
Sensor Construction: The inductive speed sensor consists of a coil of wire wound around a core, forming an electromagnetic field. The coil and core are encased in a protective housing.
Sensor Mounting: The sensor is mounted close to the rotating equipment that needs to be monitored. The distance between the sensor and the target affects the sensor's sensitivity and detection range.
Metallic Target: The rotating equipment should have a metallic component for the sensor to detect. Commonly, a toothed gear or a metal target with a pattern is attached to the rotating shaft to provide a detectable surface.
Speed Detection: As the rotating equipment moves, the metal target passes in front of the inductive sensor. The changing magnetic field caused by the movement of the metal target induces voltage and current changes in the coil of the sensor.
Signal Output: The inductive speed sensor converts the induced voltage and current changes into an electrical signal. This signal is typically in the form of a pulse or a square wave.
Signal Processing: The generated electrical signal is then processed by electronic circuitry to determine the speed of the rotating equipment. The frequency of the pulses corresponds to the rotational speed, and the sensor can be calibrated to provide an accurate speed measurement.
Applications: Inductive speed sensors are commonly used in various industrial applications, such as monitoring the speed of motors, conveyor belts, fans, pumps, and other rotating machinery.
It's important to note that inductive speed sensors are contactless and do not require physical contact with the rotating equipment, which makes them suitable for applications where non-intrusive speed sensing is necessary. Additionally, these sensors are relatively robust and can withstand harsh environmental conditions, making them a reliable choice for industrial applications.