Regulation & Efficiency Test of Single-phase Transformer by Direct Loading Method

Experiment No.: 5

Experiment Name:

Determine the regulation & efficiency of single-phase transformer by direct loading method.

Objective:

To determine

1. Regulation of single-phase transformer by direct loading method
2. Efficiency of single-phase transformer by direct loading method

Theory:

Although two chief difficulties which do not warrant the testing of large transformer by direct load test are:

1. Large amount of energy has to be wasted in such a test.
2. It is stupendous (impossible for large transformer) task to arrange a load large enough for direct loading. Yet this test can be performed to find out the efficiency & voltage regulation of small rating transformers.

Efficiency, η = Output Power / Input Power

% η =((P₂) / (P₁)) × 100

% Voltage regulation up= ((No load voltage – Full load voltage)/Full load voltage)×100

% Voltage regulation down= ((No load voltage – Full load voltage)/No load voltage)×100

Circuit Diagram:

Observation Table:

Calculation:

Apparatus Used:

Sl. No.	Name of Apparatus	Quantity	Specification	Makers name
1.	Single phase wattmeter	2	0-750-1500-3000 W 150-300-600 V 5-10 A	MECO-G
2.	Single Phase Transformer	1	230/115 V
3.	Ammeter	1	0-5 A, MI type	KEW
4.	Ammeter	1	0-10 A, MI type	Sushama
5.	Voltmeter	1	0-300 V, MI type	Sushama
6.	Digital Multimeter	1	0-750 V AC, 0-1000 V DC, 0-10 A	Akademika
7.	Rheostat	1	0-100 W, 1kW

Remarks: This method is not applicable for large rated transformer as a large amount of energy has to be wasted in such a test. During this test we should cautious about the heat radiated by the resistive load.