Question 3.
Explain the construction and working of the following. Draw a neat diagram and label it.
Electric Generator (AC)
Answer:
Electric generator AC converts mechanical energy into electrical energy.
Principle- It works on the principle of electromagnetic induction. When coil rotates in a magnetic field it induces a current in the coil and direction of induced current is given by Fleming’s right hand rule.
Construction-
It consists of a coil ABCD with two slip rings R1 and R2 connected with brushes B1 and B2 respectively. The coil is placed between two poles of a horse-shoe shaped electromagnet. Brushes are connected to a galvanometer which shows the direction of current in the circuit.
Working- When coil rotates the arm AB goes up and arm CD goes downwards, so coil rotates in clockwise direction. Applying Fleming’s right hand rule the induced current which is produced is in the direction ABCD. Current flows from brush B2 to B1. After half rotation AB comes in place of CD and CD in place of AB thus induced current flows from DCBA. Now current flow from brush B1 to B2. Thus every half rotation current flow direction is reversed thus it is an alternating current.
