Principle of Working of A.C. Generator

Principle of Working of A.C. Generator Points : Principle of Working of A.C. Generator An alternator works on the principle of Faraday’s law’s of electromagnetic induction, The working principle can be stated as, “Whenever a conductor cuts the lines of force, an emf is ‘induced in that conductor”. This induced emf is directly proportional to the rate of change of flux and number of conductors. Let there are two magnetic poles N and S and a lopp of conductor ABCD is placed in between the magnetic poles N and S. Let the loop ends are connected to two slip rings. Now whenever the conductor loop is rotated, it experiences the magnetic flux or different nature i.e. North and South. Let the direction of rotation be clockwise, the conductor be at position number 1, where the direction of motion and direction of the flux are parallel so there will not be any linkage between the magnetic field and the conductor, resulting no emf. When the conductor moves to position number 2, it experiences some linkage and producing the emf according to the Fleming’s right, hand rule the direction can be found as outwards. At position number 3, the conductor has maximum linkage and resulting the production of emf maximum in outward direction. Thus there will be some emf induced in 4th position, and in the fifth motion of conductor and flux are parallel so no emf will be produced.
In the sixth position, the direction of motion is reversed or say changed, the emf induced will be inward. At position seventh the maximum cutting angle will cause maximum production of emf as shown, at position 8th the emf will be comparatively less and at position number 1 same cycle will again start.
Now as both conductor are connected to slip rings and if we plot a graph for the values of emf thus obtained a curve will be obtained generally known as sine wave. So the emf thus obtained will have the magnitude periodically changing after a fixed interval of time, such emf is known as A.C. and the machine producing A.C. is called alternator. In alternator we are having more number of conductors, which are systematically placed over the armature to obtain a smooth curve.