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InterviewSolution
| 1. |
How does electrik generator work? |
| Answer» \tElectric generators are based on the principle of electromagnetic induction and converts mechanical energy into electrical energy.\tAn electric generator consists of a rotating rectangular coil placed between the two poles of a permanent magnet.\tThe two rings R1 and R2 are internally attached to an axle. The axle may be mechanically rotated from outside to rotate the coil inside the magnetic field.\tOuter ends of the two brushes B1 and B2 are connected to the galvanometer to show the flow of current in the given external circuit.\tWhen the axle is rotated, arm AB moves up (and the arm CD moves down) in the magnetic field produced by the permanent magnet. Let us say that the coil ABCD is rotated clockwise. By applying Fleming’s right-hand rule, the induced currents are set up in these arms along the directions AB and CD. Thus, an induced current flows in the direction ABCD. If there are more turns in the coil, the current generated in each turn adds up to give a large current through the coil.\tAfter half rotation, CD and AB reverse direction, and thus, CD starts moving up and AB starts moving down. As a result, the directions of the induced currents in both the arms change. Such a current which changes direction after equal intervals of time is called an alternating current. Thus, this device is called an AC generator.\tTo get a direct current, a split-ring type commutator must be used. The generator is thus called a DC generator.\tThe difference between direct and alternating currents is that the direct current always flows in one direction, whereas the alternating current reverses its direction periodically.\t | |