According to reports, a small windmill in your backyard, its blades turning with the incoming gust of wind, generating electricity that can be harnessed to charge your generator and power enough bulbs to light up your house. Sounds too incredulous? For retired navy captain Vijayraj Pathak, it was more a case of necessity that made him create a prototype of a windmill which can do all this and more at his farmhouse in Pirangut.
Made at a cost of less than Rs 1500, Pathak calls his windmill the ‘Aam Aadmi model’. The abundance of wind and lack of electricity at his bungalow got him thinking about using one to generate the other. The passion to put together a windmill, supported by his strong engineering background, had Pathak poring over books and the internet for research.
After eight months of trials, many a broken parts and teething troubles with what he had assembled, Pathak today has a windmill with a blade diameter of 30 inches that can generate anything from three to 10 volts of electricity.
While he doesn’t think it is a practical idea to implement in the city – which does not have the required wind-speed of 2 metre/second – he still treats his windmill as an engineering masterpiece, albeit a little crude one by his own admission.
“It has been made entirely at home, without using even a welding or lathe machine. I have also used a lot of waste material lying around the house to keep the expenses down. There was a lot of experimentation in the beginning, but once I got the voltage, I started bringing down the cost,” Pathak said.
The blades of the windmill are made with discarded drain pipes and the rotor shaft is an old and discarded exhaust fan bought from a scrap dealer for Rs 10. Two cycle hubs, purchased from a repair shop nearby, are used for propeller rotation (horizontal axis) and wind direction change (vertical axis). A steel pipe makes up the rudder, with a string hanging down to gauge the wind speed.
It’s the windmill’s generator that required the maximum engineering, he says. The generator, which works in the same way as that in a car’s alternator, has permanent magnets placed inside coils of wire. When the magnets rotate, they create a moving magnetic field. As the magnetic field changes direction, it creates an electric current in the wire. This type of electricity is called alternating current (AC), since it switches direction according to the magnetic field.
“For a long time, I could not find the kind of magnets I needed. Most would break with the large magnetic field created because of the wind. I finally managed to find the right ones in just one shop in the city and covered them with copper wires extracted from an old discarded transformer lying around,” Pathak says. He also made a crude-looking cover to prevent the magnets from flying off with the high speed of the propellers.
The final product is a robust wind-turbine, which Pathak says he wouldn’t mind putting up for display. “I want people to know that it is possible to make something like this,” he says, admitting that while the internet gives a lot of information, it does not really give out the technique. “Putting it together is where the effort is.”
While his family thought he was wasting his time, Pathak is quite satisfied with the experience. “It was a tedious process that required a lot of technique and precision,” he says.
And while one would require a battery, controller and a rectifier to make it work as a permanent source of electricity, Pathak says it’s a good thing to have lying around the house in an emergency.
“It’s definitely an alternative which can be considered by people living at high altitudes who do not have electricity,” he says. According to Pathak, even 30 km out of Pune would be a good place to start!