Due to lots of inquiries lately, we have decided to offer a basic 3 phase low rpm axial flux alternator on a stand for... whatever! It's just like those from our book Homebrew Wind Power, but set up vertically instead of horizontally. Thus, there is no furling system integrated into the geometry of the frame of this one.
This is the same basic alternator that we use for our 10' diameter wind turbine, and it is identical to the horizontal alternator we offer, but this one is set up to be mounted with a vertical axis. While we do not promote, or have a lot of faith in the cost effectiveness of the VAWT (vertical axis wind turbine) - there seems to be a lot of interest in the idea and folks want to experiment. So this alternator is designed and suitable for small VAWT experiments. It's an axial flux alternator built on a stand so that it could be bolted down for whatever application you choose.
Again, this configuration is primarily for folks wanting to experiment with vertical axis wind turbines. It is a 3 phase alternator and we will fit whatever stator you like to it, depending on your requirements. The power output depends on the load and the rpm. The practical limit for this machine is about 1000 rpm - running it faster could results in balance problems or other mechanical issues. The alternator is not safe to run over 1000 rpm.
People have used these for pedal power, hydro power, small steam engines, education, we use one on our 600 rpm Listeroid diesel engine (in that application it produces 2kW very efficiently). The alternator features two magnet rotors with a stator in between. Each magnet rotor has 12 poles (magnets). The magnets are 1" x 2" x 1/2" thick, N42 grade NdFeB.
Pictured above is the power curve for this alternator when it's clamped to a battery charging system such that open voltage of the alternator reaches battery voltage at 140 rpm. The power curve could be better, or worse, depending upon how the machine is actually loaded. For example, if we fit what we would normally call a 48 Volt stator, then the limit of the machine will be about 15 amps ~ 750 Watts @48 volts or... about 180 Watts at 12 Volts, but that 48 Volt stator will produce 12 Volts at only about 35 rpm, which... might be very suitable for a low rpm VAWT. The alternator does not cog and has no iron losses. You choose the stator of your choice. Look through the shopping cart to see power curves on our different stators. If you would like a more powerful, or efficient version of this machine ~ we can fit larger magnets for additional cost. Please contact us about that. Normally the stator is wired in WYE (star) configuration, however upon request we can bring out 3 more leads for each phase so you have the option to wire the stator in Delta. Doing so results in higher efficiency at any given voltage, but the rpm must be higher.
In short, the alternator is about exactly the same as we would build for a 10 foot diameter wind turbine. The magnet rotors are fit to a wheel hub, which runs on tapered roller bearings fit to a stationary spindle. The whole alternator is held together by 4 studs, the bolt pattern is 4 on 4 inch diameter. All of the hardware is stainless steel, and the alternator itself is powder coated with a durable hammer tone finish.
This is a powerful and efficient low rpm alternator ~ there are many smaller/must less powerful low rpm alternators available, online that are basically converted automotive alternators. This machine is in a different league.
We build these to order. Should you order one, please contact us about which stator you require and any other special requests. Expect 4 to 6 weeks for delivery.
Due to catastrophic flooding here in Colorado, our off-grid fabrication shop is inaccessable. We are attempting to relocate, but this will take some time. Please contact us first if you wish to order this product, and we can give you an estimate on how it will take us to build your order. Thanks for your patience!