Working Principle of LVDT
The working of LVDT is based on Faraday’s law of electromagnetic induction, which states that “the electrical power in the network induction circuit is proportional to the rate of change of magnetic flux in the circuit.”
As the primary winding of LVDT is connected to the AC power supply, The alternating magnetic field is produced in the primary winding, which results in the induced EMF of secondary windings.
Let’s assume that the induced voltages in the secondary windings S1 & S2 are E1 & E2 respectively. Now according tousing the rate of change of magnetic flux i.e. dΦ/dt is directly proportional to the magnitude of induced EMF i.e E1 and E2.
The total output voltage Eo in the circuit is given by Eo = E1-E2
Depending on the position of the core some cases arise:
Case 1: When The Core is Moving Towards S1
When the core of LVDT moves towards the second winding S1 then the flux linkage S will be more as compared to S2. The EMF induced in S1 will be more than the EMF of S2. Hence E1 is greater than E & net differential voltage Eo(E1-E2) will be +ve. The means output voltage Vo will be in phase with input AC voltage.
Case 2 : When the core is positioned at its null position
When the core is at a null position then the flux generated in both the secondary windings will be the same. The induced EMF E1 & E2, and both the windings will be the same. Hence the net differential output voltage Eo will be 0. It shows 0 displacement of the core.
Case 3 : When The Core Moving Towards S2
When the core of LVDT moves towards secondary winding S2 then the flux linkage with S2 will be more than S1. It means the EMF induced in S2 will be more than the induced EMF of S1
Hence E2 is greater than E1 & net differential voltage Eo (E1-E2) will be negative. It means the output voltage will be out of phase input AC voltage.
Linear Variable Differential Transformer (LVDT)
The LVDT stands for Linear Variable Differential Transformer. It converts the Linear motion into an electrical signal using an inductive transducer. Due to its superior sensitivity and accuracy over other inductive transducers, the LVDT is extensively used in many different fields. For measuring linear distance, the linear variable differential transformer (LVDT) is a precise and trustworthy tool. Today, LVDTs are used in computerized manufacturing, robotics, avionics, and machine tools, combining research facilities, high-level analysis, and analysis to detect damage caused by massive rock deformation or other movements in the subgrade of old buildings or structures. physical structure. One try. This method is used to try to detect failure in concrete slopes and warn or correct the condition. One of the special problems with historical buildings is that they can easily be damaged by small deformations in the long run.
Table of Content
- What is LVDT?
- Types of LVDT
- Construction of LVDT
- Working principle of LVDT
- Characteristics of LVDT Graph
- Advantages and Disadvantages OF LVDT
- Applications of LVDT