LINEAR VARIABLE DIFFERENTIAL TRANSDUCER (LVDT)

PREPARED BYE CHIRANJEEVIM.TECH

ASST. PROFESSORRISE KRISHNA SAI PRAKASAM GROUP OF INSTITUTIONS ,ONGOLE , AP

LINEAR VARIABLE DIFFERENTIAL TRANSDUCER (LVDT)

Principle of LVDT:

LVDT works under the principle of mutual induction, and the displacement which is a nonelectrical energy is converted into an electrical energy.

It is also called as LINEAR VARIABLE DIFFERENTIAL TRANSFORMER

Construction of LVDT LVDT consists of a cylindrical transformer where it is surrounded by one primary winding in the centre of the former and the two secondary windings at the sides.

The number of turns in both the secondary windings are equal, but they are opposite to each other.

The Primary Winding is Connected to an ac source

Working of LVDT: The Displacement to be

Measured is applied to an arm attached to the Soft iron core

Case 1: When the Core is in its normal position.

Equal Voltages induced in the two secondary windings The Output Voltage of secondary winding S1 is Es1 and secondary winding S2 is Es2 The Differential output Voltage E0=ES1~ES2

At Normal Position E0=0 ,because The Flux linking with both secondary windings is equal , hence equal emf are induced in them. (i.e ES1=ES2)

Case 2: When the Core is moved to the left of null position

Case 3: When the Core is moved to the right of null position

Cont…

Cont…

The Characteristics are linear from O-A and O-B , But after that they become non-linear.

Advantages of LVDT

Advantages of LVDT

Disadvantages of LVDT

Applications of LVDT:

1. Acting as a secondary transducer, LVDT can be used as a device to measure force, weight and pressure, etc..

2. Testing of soil strength3. PILL making Machine4. “Brain Probing” medical device5. Robotic Cleaner6. Dollar bill thickness in ATM Machine.7. Hydraulic cylinder Displacement.