, the automotive car alternator is also another popular choice among many do-it-yourself people for use as a low voltage DC generators for wind turbines. However, being a an automotive alternator bolted to the side or a combustion engine, they require high rpm speeds to generate power and are not always very efficient. Car alternators also require an external power supply voltage to power the electromagnets that create the internal magnetic field.
Car alternators limit their own current using a built-in regulator circuit which also stops the alternator from overcharging the connected batteries. However, an automotive alternator should never be connected to the battery bank in reverse or run the alternator at high speeds without the battery connected, as the output voltage will rise to high levels (much more than 12 volts) and destroy the internal rectifier.
Low voltage stand alone wind power DC systems are great for charging batteries etc, but if we want to power larger mains connected appliances or have a system that is “grid-tied” we need to either use some form of inverter to change the low voltage DC generated by the permanent magnet DC generator into a higher voltage (120 or 240 volts) AC supply, or install another different type of wind turbine generator.
In the next tutorial about Wind Energy, we will look at the operation and design of a different type of electrical machine called a