What is an LVDT?

An LVDT is a type of non-contacting linear position sensor. It is used to detect and measure linear movements in a range of industries.

LVDT stands for Linear Variable Differential Transformer, the device is constructed of a primary coil, one or two secondary coils, a ferromagnetic core (or slug), a tube or bobbin, a shield and a shaft. The ferromagnetic core is attached to a moving object and moves in a linear motion within the LVDT. The AC voltage in the coils along with the magnetic flux being produced enables the position of the core to be detected and measured. 

What are the Benefits of using an LVDT?

LVDTs are often selected for use because of the following benefits;

Long life - Because they are non-contacting, LVDTs conduct minimal friction which gives them a very long and almost infinite life. 

Quick Response Time - LVDTs will generally give a very fast response to the measuring task at hand, this makes them a popular choice in various industries.

Robust - LVDTs are robust and rugged sensors. They are able to function in harsh conditions.

Minimal Friction - As they are non-contacting there is minimal friction within the LVDT, there is less wear and tear and therefore LVDTs do not need to be repaired or replaced as often as alternative solutions. 

Infinite Resolution - because of the working principle of the LVDT it can measure the smallest changes in position. The only limitation of the infinite resolution is the noise in the LVDT signal conditioner and the resolution of the output display. The infinite resolution also guarantees outstanding repeatability. 

Single Axis Sensitivity - LVDTs only respond if the core moves along the linear axis of the coils. They tend to be insensitive to any cross-axis motion of the radial position of the core. This means that LVDTs can still function in applications involving misalignment or floating movements. 

What is an LVDT used for?

Some typical applications for LVDTs are;

• Factory automation
• General industrial applications
• Materials testing
• Process and control
• Servo mechanisms
• Pressure chambers and vessels 

LVDTs from Variohm

We have a range of LVDTs from our partner TE Connectivity.- this range includes;

AC operated LVDTs containing no electronics, suitable for applications with size restrictions or in applications with harsh operating conditions.

DC LVDTs with signal conditioning electronics built in, these require no calibration or special conditioning. DC LVDTs have current, scaled voltage or digital outputs. 

We also now supply LVDT alternatives from our sister company Positek. Positek PIPs sensors work in a similar way to LVDTs but they contain only one coil which gives them a better length to measurement ratio. Many Positek sensors are custom built onsite and can be delivered within 2 working days. Take a look at their website for full details.

Contact us to discuss your application or for more information on the LVDTs we can offer