How Displacement Causes Induced Voltage Changes in LVDTs for Position Detection

Differential Transformer Displacement Sensors (LVDTs) are precision devices used to measure linear displacement in various industrial applications. These sensors, manufactured by Shenzhen Soway Technology Development Co., Ltd., are widely used in industries such as aerospace, machinery, construction, and chemical engineering. The core functionality of Differential Transformer Displacement Sensors (LVDTs) lies in their ability to convert mechanical displacement into electrical signals through the principle of electromagnetic induction. This article focuses on how displacement causes induced voltage changes in Differential Transformer Displacement Sensors (LVDTs), enabling precise position detection.

The Principle of Electromagnetic Induction in Differential Transformer Displacement Sensors (LVDTs)

Differential Transformer Displacement Sensors (LVDTs) operate based on the principle of electromagnetic induction. They consist of a primary coil and two secondary coils wound on a hollow cylindrical form. A movable ferromagnetic core, often called the armature, is inserted into the hollow form. The primary coil is excited by an alternating current (AC) source, which induces voltages in the secondary coils.

How Displacement Affects Induced Voltage in Differential Transformer Displacement Sensors (LVDTs)

The key to the functionality of Differential Transformer Displacement Sensors (LVDTs) lies in how the position of the movable core affects the induced voltages in the secondary coils. When the core is exactly at the center of the Differential Transformer Displacement Sensor (LVDT), the magnetic flux linkage between the primary and secondary coils is symmetrical. This results in equal and opposite voltages being induced in the two secondary coils. The differential output voltage, which is the difference between the voltages of the two secondary coils, is zero at this central position.

However, when the core is displaced from the center, the symmetry of the magnetic flux linkage is disrupted. This causes a change in the induced voltages in the secondary coils. The voltage induced in the secondary coil closer to the core increases, while the voltage in the other secondary coil decreases. The differential output voltage, which is the difference between these two voltages, changes proportionally to the displacement of the core.

Position Detection through Voltage Measurement in Differential Transformer Displacement Sensors (LVDTs)

The differential output voltage is directly proportional to the displacement of the core. By measuring this voltage, the exact position of the core relative to the center can be determined. The relationship between the displacement and the induced voltage is linear, making Differential Transformer Displacement Sensors (LVDTs) highly accurate for position detection.

For example, if the differential output voltage is positive, it indicates that the core has moved towards one side, while a negative voltage indicates movement towards the other side. The magnitude of the voltage indicates the extent of the displacement. This linear relationship allows Differential Transformer Displacement Sensors (LVDTs) to provide precise measurements of linear displacement, elongation, vibration, and other position-related parameters.

Shenzhen Soway Technology Development Co., Ltd. offers a range of Differential Transformer Displacement Sensors (LVDTs), including the SDVG20 series split-type, SDVB20 series rebound-type, SDVN8-4 pneumatic, and SDVH8 pen series. These models are designed to meet a variety of industrial needs, providing high precision and reliability in position detection.