Transformers : Testing

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A transformer is essentially an equipment that steps up or steps down alternating (current)  voltages without changing the frequency. Any transformer can be used as a step up or a step down transformer depending upon the requirement. The higher voltage side carries less current and the lower voltage side carries higher current ie, N1/N2 = VI/V2 = I2/I1 whereas N1 and N2 are number of turns on primary and secondary sides, V1 and V2 are voltages on Primary and secondary and I1 and I2 are current in primary and secondary. The major parts of a transformer are two windings – primary and secondary and a core that carries the flux. The power supply on one of the windings induces a magnetic field and due to this, a voltage is induced in the other winding. This is the simple statement of Faraday’s law of induction. To carry the magnetic field that causes induction in the other field, a highly permeable magnetic material is used, so that there is no loss of flux between the windings. Any ferrous material can do this job, but to reduce loss of flux and the resultant loss in energy. In addition, the losses in the core material causes excessive heating of core, which is not desirable. So, it is important to have the best quality core in the transformer that can carry maximum flux without incurring too much loss. In the modern days, there are a number of types of core materials that really minimize the core to very great extend. The most commonly used and easy to handle among the core material is Cold Rolled Grain Oriented (CRGO) steel.

Read full article at http://electrical-engineer-diary.blogspot.in/2012/03/transformers-testing.html

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