The document discusses the measurement of displacement using a Linear Variable Differential Transformer (LVDT), detailing its principle of operation based on mutual inductance, construction, and functioning through three distinct cases. It highlights the advantages of LVDTs such as low power consumption, high sensitivity, and robustness, as well as disadvantages including sensitivity to magnetic fields and limited dynamic response. The document is presented as part of an academic assignment at the Government Engineering College, Bilaspur.

1. MEASUREMENT OF DISPLACEMENT USING LVDT
Government Engineering College, Bilaspur
Presented To:
Asst. Prof. Malka Taranum
Department of Electrical
Engineering
Government Engineering
College,
Bilaspur (C.G.)
Presented By:
Pinky Kunjam
Roll No: 300702421030
Electrical Engineering

2. LINEAR VARIABLE DIFFERENTIAL TRANSFORMER
 Principle of Working
The LVDT works under the principle of mutual inductance effect.
It is also an electromechanical-based inductive transducer that converts rectilinear
movement into an electrical signal.

3. CONSTRUCTION
 LVDT consists of one primary winding P, two secondary windings(S1& S2) and a soft iron core.
The construction of LVDT is shown in below figure.
The secondary windings are arranged on a cylindrical former with a movable soft iron core. The
primary winding is surrounded by two identical secondary windings (S1 and S2), each of which has
an equal number of turns. The secondary windings are connected in a series opposition.

4.  The soft iron core arm is connected to the part to which the displacement is to be measured. This
iron cores are subjected to hydrogen annealing in order to reduce harmonics, the residual voltage
of the core, and to increase sensitivity.

5. WORKING
 A source of constant amplitude AC power, energize the primary winding, P, of the LVDT. The
core then connects the nearby secondary windings S1 and S2, the magnetic flux is created.
According to the position of the core, the working of LVDT can be divided into 3 cases.

6. Case 1:- LVDT Core is in null Position:
When the core of LVDT is in null position, the flux linking between both the secondary coils are same,
hence voltage induced in secondary side is also equal. Hence net output voltage is
V0= V1-V2=0
Case 2:-LVDT Core is moved left of null position.
When the core of LVDT core is moved to left, then more flux links with coil S1 than S2. Hence
voltage induced in S1 is greater than S2. The net output voltage is
V0=V1-V2 is positive.
Case 3:- LVDT Core is moved Right of null position.
When the core of LVDT core is moved to right, then more flux links with coil S2 than S1. Hence
voltage induced in S2 is greater than S1. The net output voltage is
V0=V1-V2 is negative.

7. ADVANTAGES OF LVDT
LVDT has a low power consumption
It has a higher sensitive
It has a ruggedness
Easy to align and maintain
It has a wide range
It has a lower hysteresis loss
 It has a higher measurement range

8. DISADVANTAGE OF LVDT
Sensitive to a stray magnetic field
It has large primary voltage produce distortion in an output
Temperature affects the performance
It has limited dynamic response
Vibration due to displacement can affect the performance of the LVDT device
 Large displacement is needed for small output

9. THANK YOU!