21-06-2012, 02:52 PM
PROJECT ON TRANSFORMER
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INTRODUCTION
A transformer is an electrical device which is used for changing the A.C. voltages. A transformer is most widely used device in both low and high current circuit. As such transformers are built in an amazing strength of sizes. In electronic, measurement and control circuits, transformer size may be so small that it weight only a few tens of grams where as in high voltage power circuits, it may weight hundred of tones.
THEORY AND WORKING OF TRANSFORMER
When an altering e.m.f. is supplied to the primary coil p1p2, an alternating current starts falling in it. The altering current in the primary produces a changing magnetic flux, which induces altering voltage in the primary as well as in the secondary. In a good-transformer, whole of the magnetic flux linked with primary is also linked with the secondary, then the induced e.m.f. induced in each turn of the secondary is equal to that induced in each turn of the primary. Thus if Ep and Es be the instantaneous values of the e.m.f.’s induced in the primary and the secondary and Np and Ns are the no. of turns of the primary secondary coils of the transformer .
USES OF TRANSFORMER
A transformer is used in almost all a.c. operations
• In voltage regulator for T.V., refrigerator, computer, air conditioner etc.
In the induction furnaces.
• A step down transformer is used for welding purposes.
• A step down transformer is used for obtaining large current.
• A step up transformer is used for the production of X-Rays and NEON advertisement.
• Transformers are used in voltage regulators and stabilized power supplies.
• Transformers are used in the transmissions of a.c. over long distances.
• Small transformers are used in Radio sets, telephones, loud speakers and electric bells etc.