Advantages and Applications of Linear Variable Differential Transducers by Ono Sokki

Linear variable differential transducers (LVDT)are sensors for measuring linear displacement, position, or motion. They are non-contact transducers, meaning they do not have physical contact with the object being measured and therefore do not cause wear or damage. LVDTs consist of a stationary coil assembly and a movable core made of a magnetic material. When the core is displaced along the axis of the coil, it induces a voltage in the coil windings that is proportional to the distance of the core’s displacement from the center position.

Linear variable differential transducers

It can be designed with different measurement ranges and sensitivities to suit various applications. They are typically used in environments where high-accuracy measurements are required, such as in manufacturing, aerospace, and defined industries, as well as in laboratory and scientific research settings.

Linear variable differential transducers have several advantages over other types of displacement sensors. They are rugged, durable, and can operate in harsh environments and extreme temperatures. They are also highly accurate, with the ability to provide precise measurements down to the sub-micron level. Depending on the application requirements, they are versatile and can be configured to output various signal types, including AC voltage, DC voltage, and digital signals. Overall, they are widely used for measuring linear displacement and position in various applications where high accuracy and durability are essential.

How do linear variable differential transducers work?

• It consists of a stationary coil assembly and a movable core made of a magnetic material.
• The stationary coil assembly consists of a primary coil and two secondary coils wound on a cylindrical former. An AC voltage source energizes the primary coil, which creates an alternating magnetic field in the core.
• The two secondary coils are positioned symmetrically on either side of the primary coil. When the core is displaced along the axis of the coil, it changes the magnetic coupling between the primary coil and the secondary coils, which results in an output voltage proportional to the distance of the core’s displacement from the center position.
• The output voltage of this device is a differential voltage between the two secondary coils, which is proportional to the displacement of the core. The amplitude and phase of the output voltage depend on the core’s position relative to the center position of the coil.
• Typically, a signal conditioner processes the output voltage by amplifying, filtering, and linearizing the output signal to produce a calibrated and stable output voltage or current proportional to the displacement.

Advantages of Linear Variable Differential Transducers

• High Accuracy: They are highly accurate and can provide precise displacement measurements down to the sub-micron level. This makes them ideal for use in applications where high precision is required, such as in manufacturing and laboratory settings.
• Wide Range of Measurement: It can measure displacement over a wide range of distances, from a few microns to several inches. This makes them versatile and suitable for a variety of applications.
• Non-Contact Measurement: They provide non-contact measurement, which means that they do not physically touch the object being measured. This eliminates any possibility of wear and tear and also ensures that the object being measured is not affected by the measuring process.
• Rugged and Durable: They are rugged and durable and can withstand harsh environments and exposure to extreme temperatures, vibrations, and shock. This makes them suitable for use in industrial and automotive applications.
• Versatile: It can be configured to output a variety of signal types, including AC voltage, DC voltage, and digital signals, depending on the application requirements.
• Easy to Install and Use: They are easy to install and use, with no special calibration required. They also do not require any special power supply or signal conditioning equipment, making them cost-effective and easy to integrate into existing systems.

Applications of Linear Variable Differential Transducers

• Aerospace and Defense: they are used in aerospace and define applications, such as aircraft control surfaces, missile guidance systems, and robotic arms.
• Automotive Industry: They are used in automotive applications such as engine testing, suspension and steering systems testing, and crash testing.
• Manufacturing Industry: These are used in the manufacturing industry for quality control, position feedback, and process control. They are used to monitor the position of moving parts in machines, such as hydraulic cylinders, actuators, and presses.
• Medical Industry: They are used in medical applications such as monitoring the position of surgical instruments during surgery, measuring blood flow in blood vessels, and monitoring the movement of joints during physical therapy.
• Robotics: they are used in robotic systems to measure the position of robotic arms, grippers, and other components.
• Civil Engineering: They are used in civil engineering applications, such as monitoring the deformation of buildings, bridges, and other structures.
• Power Generation: They are used in power generation applications, such as monitoring the position of steam and gas turbines, and in hydroelectric power plants, to monitor the position of water gates and turbines.

Culmination

LVDT offer a range of advantages and applications in various industries. These are highly accurate, have a wide range of measurements, provide non-contact measurements, and are rugged and durable, versatile, and easy to install and use. These advantages make them ideal for use in aerospace and define, automotive, manufacturing, medical, robotics, civil engineering, and power generation industries, among others. They are used for position feedback, quality control, process control, and monitoring the position of moving parts in machines, robotic systems, and structures. Overall, they are a reliable and cost-effective solution for precise displacement measurement in a variety of applications.