Determination of Transformation Ratio of a Single Phase Transformer

Experiment No. : 5

Experiment Name :

Determination of Transformation Ratio of a Single Phase Transformer.

Objective:  

To determine transformation ratio of a single phase tranformer.

Theory:

Transformer is a static electrical a.c. powered device, which transfer the electrical power from one circuit to another circuit without changing its frequency.

The level of voltage may be stepped up or down depending upon the number of turns on low voltage side winding and high voltage side winding. If we connect the ac power supply with low voltage side winding, then the winding is considered as Primary Side. And the remaining winding, i.e. high voltage winding, from which we take power output, is considered as Secondary Side.

And if we connect the ac power supply with high voltage side winding, then the winding is considered as Primary Side. And the remaining winding, i.e. low voltage winding, from which we take power output, is considered as Secondary Side.

So, there is a ratio, depending on which, the level of voltage is stepped up or down, that is called, Transformation Ratio.

The transformation ratio is defined as the ratio of secondary voltage to primary voltage. The transformation ratio is indicated as K.

If the value of K is-

• greater than 1. Then the transformer is step up Transformer
• less than 1. Then the transformer is step down Transformer
• equal to 1. Then the transformer is isolator Transformer

As, K is the ratio of two same quantity, so it is unitless.

Circuit Diagram:

Observation Table:

Sl.No.	Primary Voltage (V1) volt	Secondary Voltage (V2) volt	Transformation Ratio (K= V2 / V1 )	Remarks
1.	230	124.7	0.54	Step down transformer
2.	115	212.9	1.85	Step up transformer
3.
4.

Apparatus Used:

Sl. No.	Name of the Apparatus	Quantity	Specification	Maker’s Name
1.	Single phase Transformer	1	230/115 V, Shell type, Air cooled
2.	Digital Multimeter	1	0-10 MΩ, 0-750 V, 0-10 A	Akademika

Remarks:

The transformation ratio is calculated by measuring the primary voltage and secondary voltage.