InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
What will happento the secondary current if number of turns of secondary increases |
| Answer» <html><body><p>Basically the question is about the Step-Up <a href="https://interviewquestions.tuteehub.com/tag/transformer-1425788" style="font-weight:bold;" target="_blank" title="Click to know more about TRANSFORMER">TRANSFORMER</a>, So let’s first discuss why the voltage increases and then later we will discuss why the current decreases,So a Step-up transformer looks like thisAs you can see the number of turns in primary is less than the number of turns in the secondary. The number of turns <a href="https://interviewquestions.tuteehub.com/tag/depends-948548" style="font-weight:bold;" target="_blank" title="Click to know more about DEPENDS">DEPENDS</a> upon the transformation ratio of the transformer. The voltage which is transferred from the primary to the secondary depends upon induced Electromagnetic Force. The more turns the secondary winding has in relation to the primary winding, the larger the induced secondary EMF and so the voltage in the secondary winding.So now we are done with the voltage issue which was very basic in understanding now let’s see why the current decreases even though voltage increased. To explain these there are two ways <a href="https://interviewquestions.tuteehub.com/tag/one-585732" style="font-weight:bold;" target="_blank" title="Click to know more about ONE">ONE</a> easy and other little complex.Let’s first discuss easy one,According to definition of transformer,‘Transformer is a static device which transforms electrical energy from one circuit to another without any direct electrical connection and with the help of mutual induction between two windings. It transforms power from one circuit to another without changing its frequency and Power but may be in different voltage <a href="https://interviewquestions.tuteehub.com/tag/level-1072714" style="font-weight:bold;" target="_blank" title="Click to know more about LEVEL">LEVEL</a>.’So as the definition says the power does not changes in an Ideal transformer. Power is generally a product of the current and the voltage so as the voltage is increasing the current has to decrease in the step-up transformer.It’s time for the complex one,According to Maxwell’s fourth equation in frequency domain which is,▽×H = (σ + jωξ)EThe sigma(σ) in the above equation accounts for Conduction current and the other part jωξ is <a href="https://interviewquestions.tuteehub.com/tag/displacement-956081" style="font-weight:bold;" target="_blank" title="Click to know more about DISPLACEMENT">DISPLACEMENT</a> current. The conduction current is always orthogonal or perpendicular to the displacement current because the term j present which gives 90 degrees shift. So in transformers case,Primary current passes through the windings as conduction current and the remaining passes as displacement current perpendicular to the conduction current in the dielectric medium. The windings have inductive reactance associated with them that means the windings oppose the current flow them.</p></body></html> | |