Making your own generator or alternator is quite complicated and can be expensive (see our Guide to Axial Flux Wind Turbine Alternator Construction. It is perhaps the best method to use for a large DIY wind turbine generating over 300 Watts, or for a small demonstrator which you can build to better understand how wind turbines actually generate electricity.
However if you would like to make a relatively cheap wind turbine generator to generate a couple of hundred watts of power, then you can do a lot worse than using a DC motor as a DC generator. All you then need to do is fit some PVC wind turbine blades (or wooden blades if you like carpentry) to the motor, put it on a pole, and you have your very own wind turbine.
When choosing a motor to use as a DC generator there are a few important things to look out for. You want the motor which generates the highest voltage at the lowest RPM. A motor rated at 40 Volts at 10,000 RPM for example, would not be able to charge a 12V battery bank unless it was spinning at thousands of revs per minute – not practical for a wind turbine generator.
Therefore wind turbine enthusiasts have homed in on motors which generate say 30 volts at 300 RPM. These include many treadmill motors and some of the motors made by Ametek. As long as the copper windings inside are thick enough, these motors can generate a good battery charging voltage and carry a useful current at the sort of RPMs typical of wind turbines in low winds.
Here is a video which explains why Ametek motors are far more suitable for wind turbines generators than most other motors – even those sold as ‘wind turbine’ generators – because they do not need constant high winds to generate decent amounts of electricity (without the need for an inefficient gearbox):
Ametek PM Motors for Wind Turbines
Not all Ametek PM (Permanent Magnet) Motors are suitable for use as wind turbine generators. Models to look out for are:
Ametek 30VDC – 30VDC at 325 RPM
Ametek 40VDC – 40VDC at 1050 RPM
Ametek 50VDC – 50VDC at 1200 to 1800 RPM (depending on the exact model)
Ametek 99VDC – 99VDC at 535 RPM
The Ametek 99VDC is the best for most wind turbine applications, however they are very hard to come by.
Find out about how one enthusiast built themselves a wind turbine generator using an Ametek PM Motor as a Generator.
Buy an Ametek PM Motor
As it is usually very difficult to find an Ametek motor, the best place to start your search is eBay. Click here for a well refined (vacuum cleaner parts etc removed) ebay search for Ametek motors now. There are usually a few good motors to be found there.
If you do not find a suitable Ametek motor for sale, click here for another refined search for Treadmill Motor to view some similar (and usually cheaper) products. There are usually many more treadmill motors available than Ametek motors so you should be able to find something suitable. They are not as sturdy as the Ametek motors, but they offer similar high torque low RPM specs.