Author Options:

Lawn tractor magnito for wind power generation? Answered

Lawn tractors have AC alternators built around the crankshaft with a rectifyer to DC. Would a wind generator using this for the power generator work, and how much power would it make?


I have a couple iron cores with copper windings on them. They came off a small engine. I have wondered myself if i were to rewind the the core and make it 3 phase and add more magnets to the flywheel. The iron core only uses about 1/3 of the winding spaces avilable.

Jim L.

8 years ago

   I don't know much about the subject, but are you asking about a magnito or an alternator?  I do know that a magnito works by passing a strong magnet on a fly wheel attached to the crankshaft past an iron and copper (wire coil) pile at close proximity and  "high" speed. 

   It has the advantage of creating an electrical pulse to a spark plug at exactly the right moment to fire the appropriate cylinder of an engine to turn the mag for the next firing.  Excess pulses are sent to an accumulator, D/C converter, and battery.

   I've often wondered the same thing using a vertical roof turbine as my "wind mill".  The advantage here would be not needing to "weather vane" the mill and taking advantage of smaller space.

First, in reference to another comment made here, "Windmill" generators do not need a battery to start, they turn when wind blows through them, if you're using a geared or motor driven alternator you need to rethink your design.
Second, the alternator question depends on type of mower, mechanical or electrical blade clutch. This is because an older or cheaper mower with a mechanical blade clutch only uses the power to activate the ignition system, headlights if available and the charging circuit for the battery.  An electric blade clutch however has to provide additional power to activate a heavy magnetic solenoid that releases the blade brake, hence it's alternator will produce more energy at the same rpms.
Now, lawn mowers for consumers generally run less than 3000 RPMs full open, and will produce 12V at < 10 amps. Some can produce a little more but if we're talking about an older mower, that's not likely.
Now with all of that out of the way I can tell you that most Windmill generators made at home are created using a GM single wire alternator either belt driven or mounted to the blade shaft. They can produce 12V at upwards of 60 amps depending on the coil load inside. They are easy to find and one wire hook up makes them easy to attach and wire into your system. If you're like me you may be using a standard portable car inverter to boost the 12V to 120V, just make sure you don't exceed the RMS rating of your inverter.

It would work if you can figure out how to get the windmill to turn it fast enough.

How much power it would generate is impossible to tell since you are not able to give use any spec's. of the equipment.

How much power can you wind mill put out to turn your generator?
How much power does it take to turn your generator?
How much power can your generator put out at that speed?

You have to answer these questions yourself since we can't tinker with your toys.

.  It should work, but you may need a battery to energize it during startup.
.  If it's just a small lawn tractor, the alternator probably isn't going to put out much power. If you can't find a Watt (or volts and current) rating on the alternator, look in your manual or the manufacturer's web site.