What is a linear variable differential transformer (LVDT)?
1 Answer
A Linear Variable Differential Transformer (LVDT) is a type of electromechanical sensor or transducer used for measuring linear displacement or position. It is a highly accurate and reliable device that converts the linear motion of an object into an electrical signal. LVDTs are commonly used in various industrial and scientific applications where precise position sensing is required.
The basic construction of an LVDT consists of three coils: one primary coil and two secondary coils. The primary coil is the central coil, while the two secondary coils are symmetrically wound on either side of the primary coil. The coils are typically made of insulated wire wound on a hollow cylindrical form.
The operation of an LVDT is based on the principle of electromagnetic induction. When an alternating current (AC) is applied to the primary coil, it generates an electromagnetic field around it. When the core (usually made of a ferromagnetic material) is placed inside the hollow space of the coils and subjected to linear displacement or movement, it causes a change in the magnetic coupling between the primary coil and the two secondary coils.
As the core moves, the induced voltage in each secondary coil changes proportionally to the displacement of the core. The two secondary coils are connected in a way that their output voltages are equal in magnitude but opposite in phase. The net output voltage is the difference between the two secondary voltages and is proportional to the displacement of the core.
One of the significant advantages of LVDTs is that they can provide highly accurate and frictionless position measurements with excellent repeatability and linearity. They are widely used in various applications, including industrial automation, quality control, material testing machines, aircraft and aerospace systems, robotics, and more. Their rugged design and reliability make them well-suited for harsh environments and long-term operation.
The basic construction of an LVDT consists of three coils: one primary coil and two secondary coils. The primary coil is the central coil, while the two secondary coils are symmetrically wound on either side of the primary coil. The coils are typically made of insulated wire wound on a hollow cylindrical form.
The operation of an LVDT is based on the principle of electromagnetic induction. When an alternating current (AC) is applied to the primary coil, it generates an electromagnetic field around it. When the core (usually made of a ferromagnetic material) is placed inside the hollow space of the coils and subjected to linear displacement or movement, it causes a change in the magnetic coupling between the primary coil and the two secondary coils.
As the core moves, the induced voltage in each secondary coil changes proportionally to the displacement of the core. The two secondary coils are connected in a way that their output voltages are equal in magnitude but opposite in phase. The net output voltage is the difference between the two secondary voltages and is proportional to the displacement of the core.
One of the significant advantages of LVDTs is that they can provide highly accurate and frictionless position measurements with excellent repeatability and linearity. They are widely used in various applications, including industrial automation, quality control, material testing machines, aircraft and aerospace systems, robotics, and more. Their rugged design and reliability make them well-suited for harsh environments and long-term operation.