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KITE VICTERS ONLINE CLASS 07-09-2021, , PHYSICS – X-PART-04 CLASS 22, , AC - Generator, Working principle : Electromagnetic Induction, Energy change : Mechanical Energy, Electrical Energy, , The main Parts of AC generator, , * Field magnet (NS), The magnet that creates magnetic flux in the generator., , * Armature (ABCD), An arrangement of insulated conducting wire wound on a soft iron core. This can be, made to rotate about an axis., * Slip rings (R1,R2), Metal rings which are welded together with the armature coil. They rotate, along with the armature on the same axis of rotation as the armature, * Brushes(B1,B2), They are arrangements which always make contact with the slip rings., Current flows through them to the external circuits., * When the coil rotates about the axis in the clockwise direction, the portion AB moves, upward and the portion CD moves downward., page 1, , www.apluseducre.blogspot.com or Whatsapp 9746544422

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KITE VICTERS ONLINE CLASS 07-09-2021, , Then according to the Fleming’s Right Hand Rule What is the direction of induced, current in the portion AB?, * From A to B, What is the direction of induced current in the portion CD?, * From C to D, What is the direction of induced current in the coil ABCD?, * From A to D, What is the direction of induced current in the external circuit? (through the, galvanometer), * From B 2 to B 1, What will be the positions of AB and CD when the armature completes, 1800 or one half rotation?, * AB will be near the south pole of the magnet and CD will be near the north, pole., At this instance,, What is the direction of movement of AB?, * Downward, What is the direction of movement of CD?, * Upward, What is the direction of current in the armature?, * From D to A, What is the direction of current through the external circuit, (through the galvanometer)?, * From B1 to B2, * The direction of current reverses during every half rotation of the armature, and that the magnitude of current is increasing and decreasing., Period T, The time taken by the armature coil for a full rotation is called the period, T., Time taken for half rotation (1800 ) is T/2., , page 2, , www.apluseducre.blogspot.com or Whatsapp 9746544422

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KITE VICTERS ONLINE CLASS 07-09-2021, , The frequency of AC, * In an AC generator, the induced emf generated in the first half rotation in one, direction and that generated in the second half rotation in the opposite direction, together form the cycle of AC., * The number of cycles per second is the frequency of AC., * The frequency of AC generated for distribution in our country is 50, cycles per second or 50 Hz., * If the frequency of AC is to be 50 Hz, the armature coil is to rotate fifty times, per second. How to overcome this practical difficulties?, The number of rotations is reduced by increasing the number of armature coils, and the number of pole pieces of the field magnet in a generator., Assignment, 1., , page 3, , www.apluseducre.blogspot.com or Whatsapp 9746544422