converting an old brush cutter into a generator

[river place]

When we first bought our 6+ acres in central Arkansas it was very over grown.  I found a Swisher 24" rugged cut brush cutter at a Tractor supply that had been returned.  It was like new and I got it for $300 off.  If did the job to cutting down the heavy brush for a driveway, and place to build a barn and place a travel trailer and cut some trails to the river.  Used it off and on for another year or two to keep the brush in check.  We've since moved on to a tow behind mower deck for the ATV so the brush cutter is just sitting with only about 20hrs on it.

I thought about selling the cutter but I could not get the belt to slip enough to disengage the drive.  I didn't want to sell until I fix this.  Then I got to thinking why not use the engine and chassis to build a generator?  I know there are generators on the market for around $500.00 but how good are they plus I might enjoy the challenge to building my own.

Chassis is heavy gauge steel so easy to bolt and weld to.  Engine is an 11.5 HP B/S with verticle output shaft.  Has a 4 speed transaxle with reverse for self propelled use.

It seems much easier to build a generator if the output shaft is horizontal which my engine isn't. 

Does anyone know of a source for AC or DC generators that may work for me.  I've seen kits using car alternators for 12V DC mounted verticle and then use an invertor to get AC out.  I would have thought the car alternator would provide enough current considering a 90amp alternator for power tools unless you charge batteries then convert to AC.  Goal was to make the thing somewhat portable.

If not going to DC is there and AC generator that can be mounted verticle or is there a differential type unit to convert the output to horizontal?

From what I read the engine may need to run at 3500 rpm to generate enough voltage (120v) if geared 1 to 1 into an AC generator.  With the 11.5 HP engine I could lower the rpm to save fuel and use gears or pulleys to gear up the generator input.

The self propelled drive on the mower doesn't seem to offer the gearing to be used to convert the engine output to horizontal as the wheels turn slow (not enough RPM).

Anyway this is something I'm considering to repurpose the cutter.

[Redoverfarm]

Not real sure what the original price was or what you feel that it is worth now but you may be well ahead to try to sell it and purchase or apply the money toward a ready made generator.  That is unless you are a tinkerer and just want a winter time project. 

[rick91351]

I think your time would be better served watching Cragslist for generator buys.  One friend of mine from work scored two nearly new Honda generators that run in parallel with a jumper for pennies on the dollar.   Bought one then waited a month or so and another one came along.  He uses them on his boondocked fifthwheel camper.  He never uses an improved camp ground.     Generators are one of those things that everyone has to have then...........   ......................  What the heck did I buy that for?  Just an idea but I said Edison was wasting to much time with that light bulb thing.....

[MountainDon]

Does anyone know of a source for AC or DC generators

Northern tool is one

I read the engine may need to run at 3500 rpm to generate enough voltage (120v)

The issue is how to get and maintain the frequency at or as close to 60 Hz.  Most generators run at 3600 RPM to achieve that. They have a governor assembly on or under or near the carburetor. As the electrical load changes the engine speed must be held as close to the correct speed as possible.


IMO, unless this is a project you just have to get involved in, selling the un-needed tool and buying the desired tool makes more sense.

[firefox]

Like Don said, it is non trivial to generate A/C due to maintaining frequency. If
you want to tinker, get some dc car generators and charge a battery bank or some such. You can get 12 volt or 24 volt generators. They use the 24volt generators in mil trucks, so you might get a deal at a mil surplus store.
Bruce

[flyingvan]

Around here, many people buy generators before big storms, never use them, and get rid of them.  People that do use them tend to upgrade.  Have you considered running a free Craigslist ad for a trade--My brushcutter for your generator?  Seems to me there are quite a bit more generators than brushcutters out there

  What's the nearest big city---Fort Smith?  'K lessee here...... Oh look--there are three different people wanting to barter generators.  Want diesel or gas?  http://fortsmith.craigslist.org/bar/3555659441.html      http://fortsmith.craigslist.org/bar/3487334947.html   http://fayar.craigslist.org/bar/3567370589.html 

[river place]

Yeah after some thought maybe I should try to get the drive to disengage then sell it and put the funds into a good quality generator with an inverted for clean power for electronics.  Drive is just tension on belt when engaged but even when backed off if still wants to drag on the transaxle pulley.

[roadtripray]

I just bought a 4000 w Champion generator from Tractor Supply two weeks ago.  I've been using it daily and it has started on the first pull (except when I forget to turn the switch to "ON" first  ) every time.  They had it on sale for $299.99, regular 329.99 I think.  It's rated about 12 hours runtime on a 4 gallon tank at 50% load.  From what I've seen I think my efficiency has been pretty close to that.

Peace,
Ray