Differencing the two secondary voltages results in a voltage proportional to the core’s distance from null. As the name suggests, many people get confused that it is a Transformer. FIG1– LINEAR VARIABLE DIFFERENTIAL TRANSFORMER • THE TRANSFORMER CONSISTS OF A SINGLE PRIMARY WINDING P1 AND TWO SECONDARY … However, it is possible to use an LVDT beyond its specified measuring range, with a predefined table or polynomial function that provides compensation for the nonlinearity. The output from a linear variable differential transformer is a direct, linear function of the input for its specified measuring range. As the core moves to one side of the null position, the magnitude of one secondary becomes greater than the other. ... Hydrogen annealing is done on Iron core to reduce harmonics, residual voltage of core and thus provides high sensitivity. 2. An LVDT is designed to have symmetric measurement ranges on each side of null. The residual voltage is because of the complex nature of the electrical model of a linear variable differential transformer which comprises of parasitic capacitances of the windings. It is very accurate inductive transducer as compared to other inductive transducers. Laminated core is also used for the same purpose. This slot cut the magnetic field created hence reducing the flux. Ideally, the output voltage at the null position should be equal to zero. Characteristics of LVDT & its significance Characteristics of LVDT Significance:-As the core is moved in one direction from the null position, the differential voltage i.e. The resulting higher voltage of the first secondary in relation to the second secondary causes an output voltage that is in phase with the primary voltage. Figure 6: Half-bridge LVDT configuration Note that the LVDT concept can be implemented in rotary form, in which case the device is called a rotary variable differential transformer (RVDT). Types of LVDT based on applications: 1. The effective voltage and LVDT output is the difference between each secondary. This causes power loss in the core. However, in actual practice, there exists a small voltage known as Residual Voltage, at the null position. the difference of the two secondary voltages will increase while maintaining an in-phase relationship with the voltage from the input source. Definition of LVDT. This may be by virtue of the presence of harmonics in the input supply voltage and also due to harmonics produced in the output voltage on account of the use of the iron core. General Purpose LVDT: for use in many industrial and research applications. • Slotted longitudinally to reduce eddy current losses. In Figure 1, as the core moves over S1, the voltage output of … When the core moves away from the center of the LVDT, known as the null point, the signal from the primary will be coupled to one secondary more than the other. The half-bridge LVDT does not produce a null voltage, and the A/B ratio represents the range-of-travel of the core. The maximum value of E OUT occurs at maximum core displacement from null (center) position and is a function of the amplitude of the primary-side excitation voltage and the sensitivity factor of the particular LVDT; typically, it is fairly substantial at several volts (RMS). An LVDT (linear variable differential transformer= is an electromechanical sensor used to convert mechanical motion or vibrations, specifically rectilinear motion, into a variable electrical current, voltage or electric signals, and the reverse. LVDT full form is Linear Variable Differential Transformer. Cross-Sectional View of LVDT Core and Windings Displacing the core to the left (Figure 4) causes the first secondary to be more strongly coupled to the primary than the second secondary. 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