Question

Explain the working of a windmill with a simple neat sketch. How is its energy output used?

Answer 1

1. When the wind strikes the rotor blades, blades start rotating.
2. The turbine rotor is connected to a high-speed gearbox.
3. Gearbox transforms the rotor rotation from low speed to high speed.
4. The high-speed shaft from the gearbox is coupled with the rotor of the generator and hence the electrical generator runs at a higher speed.
5. An exciter is needed to give the required excitation to the magnetic coil of the generator field system so that it can generate the required electricity.
6. The generated voltage at the output terminals of the alternator is proportional to both the speed and field flux of the alternator.
7. The speed is governed by wind power which is out of control.
8. Hence to maintain uniformity of the output power from the alternator, excitation must be controlled according to the availability of natural wind power.
9. The exciter current is controlled by a turbine controller which senses the wind speed.
10. Then output voltage of the electrical generator(alternator) is given to a rectifier where the alternator output gets rectified to DC.
11. Then this rectified DC output is given to the line converter unit to convert it into stabilized AC output which is ultimately fed to either the electrical transmission network or transmission grid with the help of a step-up transformer.