ALTERNATING CURRENT — Physics STD 12 Science — Question
Gujarat BoardEnglish MediumSTD 12 SciencePhysicsALTERNATING CURRENT2 Marks
Question
Explain the energy losses in a transformer.
✓
Answer
(1) The flux leakage : There is always some flux leakage. i.e. not all the flux due to primary passes through the secondary. (due to poor design of the core or the air gaps in the core). →Sol. : It can be reduced by winding the primary & secondary coils one over the other. (2) Resistance of the windings : The wire used for the windings has some resistance and so, energy is lost due to heat produced in the wire ( $I^2 R$ ). →Sol. : This can be minimized by using thick wire in high current, low voltage windings. (3) Eddy currents : The alternating magnetic flux induces eddy currents in the iron core and causes heating. →Sol. : The effect can be reduced by housing a laminated core. (4) Hysterisis : The magnetisation of the core is repeatedly reversed by the alternating magnetic field. The resulting expenditure of energy in the core appears as heat. →Sol. : Can be reduced by using a magnetic material which has low hysterisis loss.
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