In-depth Tutorial on Linear Position Sensors (LVDTs)
by Greg on Dec.02, 2010, under Android
What is An LVDT?
The letters LVDT are an acronym for Linear Variable Differential Transformer, a standard variety of electromechanical transducer which can convert the rectilinear motion of an object to which it really is coupled mechanically right into a corresponding electrical signal. LVDT linear position sensors are available which can measure movements as small as a couple of millionths of an inch as much as several inches, but also are able to measuring positions as much as ±20 inches (±0.5 m).
The transformer’s internal structure includes a first-rate winding centered between a couple of identically wound secondary windings, symmetrically spaced concerning the primary. The coils are wound on a one-piece hollow type of thermally stable glass reinforced polymer, encapsulated against moisture, wrapped in a high permeability magnetic shield, after which secured in a cylindrical stainless-steel housing. This coil assembly is typically the stationary section of the location sensor.
The moving component to an LVDT is a separate tubular armature of magnetically permeable material called the core, that’s free to transport axially inside the coil’s hollow bore, and mechanically coupled to the article whose position is being measured. This bore is usually big enough to present substantial radial clearance between the core and bore, with out physical contact between it and the coil.
In operation, the LVDT’s primary winding is energized by alternating current of appropriate amplitude and frequency, referred to as the first excitation. The LVDT’s electrical output signal is the differential AC voltage between the 2 secondary windings, which varies with the axial position of the core in the LVDT coil. Usually this AC output voltage is converted by suitable electronic circuitry to high level DC voltage or current it truly is less demanding to exploit.
Macro Sensors offers an in depth line of LVDTs including AC- and DC-operated versions, linear and rotary sensors, free core and spring-loaded technology, hermetically sealed and extreme temperature resistance units in addition to custom products. Macro Sensors’ extensive line of LVDT-based linear and rotary sensors are used for linear position measurement and feedback in lots of industrial applications including factory automation, motion control systems, metal fabricating, automotive assembly in addition to power plants, gas/steam turbines. For a catalog of Macro Sensors complete line of LVDTS, talk to the website at: http://www.macrosensors.com
