Basic Electrical

Unlike two winding transformer, an auto-transformer contains only one winding. This single winding serves the purpose of both primary as well as secondary. As this transformer employs only one winding, it uses less copper. Hence it is cheaper and more efficient.

Figure 1: Open Delta Connection of Transformer.

Current inrush phenomenon in transformer is the flow of high magnetizing current for short time in primary winding when the transformer is switched ON at the instant when applied voltage is zero.

Figure 1: Sumpner’s Test (Back to Back Test) of Transformer. Sumpner’s test is the improved method of determining the regulation, efficiency and heating on load conditions than O.C and S.C tests. This test requires two similar transformers, which can be connected to the supply in such a way that one is loaded on other. The

Depending upon the type of core used there are two types of transformers in practice. They are, Core type transformer Shell type transformer. Core Type Transformer   Figure 1: Core Type Transformer.