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x39
07-16-2006, 10:17 PM
I'm thinking about putting electrics on my old garden tractor, and was wondering if anyone can tell me whether automotive alternators are designed to turn in only one direction or whether direction of rotation doesn't matter. Thanks.

J. R. Williams
07-16-2006, 10:25 PM
The typical alternator might have problems with cooling as the fan may be direction sensitive and the nut holding the fan and pulley on the shaft might work loose. The use on a garden tractor would be less severe than in an automobile as to heat and rapid acceleration.

JRW

Fasttrack
07-16-2006, 10:36 PM
Most of the alternators i've seen are one-directional because of the fan and nut as JRW mentioned. Also, as the name implies, it produces alternating current. Just something to keep in mind sense most of the charging systems i've seen on lawmowers are dc generators.

agrip
07-16-2006, 10:47 PM
X - -
Most small units have the pulley either keyed or tight enough that the nut will not come loose easily.
It that should occur (not likely) use loctite.

Forwards or backwards tilt to an alternator fan wont make a lot of difference. The only time a forward tilt does make a difference is when freeflowing air passes through a fan big enough to overload the driving motor.
This is NOT the case with alternator.

Otherwise the alt. does not care which way it turns.

I suggest that you use an internal rectifier and regulator (GM style) so that you can have a single wire out, supplying DC.

Hth Ag

J Harp
07-16-2006, 10:47 PM
X39

If the alternator will be belt driven you can set it up so it will turn in the correct direction when you build the mounting parts. Say the pulley on the left causes the wrong rotation, then turn the alternator so the pulley is on the right and it will run the right direction, that is assuming that mounting it that way dosen't leave it hanging out in thin air, if that happens you might have to get creative with idler pulleys and such to bring it inbord. Good luck with it.

CCWKen
07-16-2006, 11:00 PM
No need for a big hogg'n GM alternator on a small tractor. This one is 12v/~45A and came from a Subaru Justy. It's about 4" in diameter. Your local auto salvage is probably filled with like kinds. This is just one of them. A three-wire hook up is simple. It's still internally regulated.

http://img.photobucket.com/albums/0903/CCWKen/Projects/Grader/GraderAlternator.jpg

RobDee
07-17-2006, 12:11 AM
Most alternators have diodes built in and are three phase which means you can run pretty clean right out of the box. Nuts and fans aside they can run in either direction. Just remember to keep the rpms up if you want any power out and that means at least 2k to 3k rpms.
Rob Dee

x39
07-17-2006, 07:53 AM
Thanks all for taking the time to reply. I hadn't even thought about the fan, my primary thought was about output. Looks like the alternator on the tractor in the image supplied by CCWKen doesn't even have a fan (or perhaps it's in the housing?) Is that a Nippon-Denso unit? Probably common to lots of small Japanese vehicles. I'm going to have to scrounge one of those up, might be fun to play with. My original thought was to use one off a Chevy, I've probably got a dozen of them laying around the place, plus I have a simplified wiring diagram that I found on the net a while back. Good answers as always, thanks again.

A.K. Boomer
07-17-2006, 08:16 AM
I would try and spin it in the direction for which it was designed for, Iv been almost all japaneese for way over a decade now so havnt seen a ton of other stuff apart but when it comes to most nipondenso's and mitsuboshi's the brush pack is offset as compaired to the armature, this means it is a uni-directional alternator, run it in the way it was designed for, it will also help it cool better,,, there are many automotive little P-shooter alternators out there now and all the ones i know of are internally regulated, you can also find permanent magnet little generators on everything from other lawn equip. to lightduty heavy equip. good luck...

ProGunOne
07-17-2006, 11:48 AM
"doesn't even have a fan (or perhaps it's in the housing?)"

The fan is located and held in place just behind the belt pulley. You can't see it from the angle of his picture, but I'm sure it's there. You can usually tell the intended rotation/direction by the way the fins on the fan are slanted. By looking at the one in the picture from the front of it, it appears that it's run counterclockwise.

http://img387.imageshack.us/img387/3505/alternatorkm6.jpg (http://imageshack.us)

Timleech
07-17-2006, 12:37 PM
"doesn't even have a fan (or perhaps it's in the housing?)"

The fan is located and held in place just behind the belt pulley. You can't see it from the angle of his picture, but I'm sure it's there. You can usually tell the intended rotation/direction by the way the fins on the fan are slanted. By looking at the one in the picture from the front of it, it appears that it's run counterclockwise.

http://img387.imageshack.us/img387/3505/alternatorkm6.jpg (http://imageshack.us)

Clockwise from the front on that one, normal vehicle engine rotation.
This rotation thing crops up now & then on marine engines, a lot of older ones turn the opposite way, and someetimes alternators have to be fitted back to front. In the UK you used to be able to get reverse rotation fans, until the makers realised they actually shifted enough air even running the 'wrong' way.

Tim

x39
07-17-2006, 01:17 PM
[QUOTE=ProGunOne] You can usually tell the intended rotation/direction by the way the fins on the fan are slanted. [QUOTE]
An excellent tip! I'd have overlooked that.

Ausserdog
07-17-2006, 01:56 PM
If rotation is a concern - I don't think it really is - try an alternater from a Honda. If memory serves correctly most Honda engines run in the opposite direction as other cars.

CCWKen
07-17-2006, 03:35 PM
The one I'm using (in the picture) is a Mitsubishi by Fuji Heavy Industries. The fan is internal and really doesn't matter which way you turn it. It will push or pull air through. There shouldn't be a problem with rpm either if you're using a lawn tractor engine. These are usually set to run around 3200rpm. (Much lower than rated rpm ~ 3600.) For the sake of the bearings, I'd make your drive pulley spin it at no more than 5-6k rpm at peak.

The engine in the picture is a Kubota diesel that runs, max, at about 2000rpm most of the time. It has a 1.5 to 1.0 drive pulley. Once you get over about 400rmp, the regulator/charge circuit will kick in and stay till you shut it off. Those big turd GM's won't do that. ;)

If you get a salvage yard alternator, try to get the plug too and a foot or two of the wire harnes. It makes for a clean installation. The pin-out indication for the wires is right on the label or the alternator in most cases.

We wanna see pics of what you're build'n! :D

Forgot to mention, I have a Nippon-Denso unit but it's larger than the Fuji.

ProGunOne
07-17-2006, 06:33 PM
"The engine in the picture is a Kubota diesel that runs, max, at about 2000rpm most of the time."

I thought I recognized that oil filler cap, starter, and oil filter sticking out the side. We run the Kuboto's (3 cyl. IIRC?) for powering generators on some of our machinery at work. Very dependable engines. I have yet to see one fail. The generators burn out after about 8-9,000 hours but we always change them out as one complete unit? I beleive there's an oil filler cap on the front cover timing gear cover?

CCWKen
07-17-2006, 08:09 PM
I've got a 3-cylinder waiting to become something. Haven't fixed what to build yet. This one's a two-banger. It came out of a G3200 Kubota Garden Tractor. I used pieces to build a "Kenbota" tractor with grader blade and FEL.

http://img.photobucket.com/albums/0903/CCWKen/Projects/Grader/GraderEngine01.jpg

LarryinLV
07-18-2006, 12:50 PM
Using an idler pulley and a serpentine belt and you can spin your alternater in any direction you want. This also helps in tensioning 'cause you can slot the idler to swing out of the way for a new belt or to tighten when needed. Weld a bolt head at the opposite side from the mounting bolt and you can use a breaker bar to pull the belt (rotate the idler) tight.

RPease
07-18-2006, 01:32 PM
I'm surprised that someone hasn't mentioned that you can use a v-belt in a "figure-8" orientation and turn the pulley in the opposite direction. Will have to mount the alternator a little "off axis" to let the belt sides clear, but they used to do that with flat belts on farm implement power take-offs for years.

Of course........that was "rocket science" back then..........:D

Rodg

ProGunOne
07-18-2006, 05:21 PM
I used pieces to build a "Kenbota" tractor with grader blade and FEL.

:D :D

How about a picture of the Kenbota?

CCWKen
07-18-2006, 07:53 PM
I know a lot of old group will be rolling their eyes on this. :D If you do a search on "Kenbota", the build sequence is out there. With fear of ridicule, here she be!

http://img.photobucket.com/albums/0903/CCWKen/Projects/FEL/2005_1212Kenbota0002.jpg

wierdscience
07-18-2006, 09:10 PM
The GM alternators have one drawback,the brushes are off center biased toward CW rotation,CCW rotation will shorten the're life.

x39
07-18-2006, 10:01 PM
I had an interesting conversation with a guy at the local (if sixty miles away can be considered that anywhere but here, LOL!) auto electric shop. He said that on applications such as tractors where the only equipment one would probably run are headlights, a cooling fan is of questionable utility.

Wareagle
07-18-2006, 11:47 PM
CCWKen, there's nothing wrong with the Kenbota! Looks good.

How well does the bade work for you?

ProGunOne
07-19-2006, 06:11 PM
"CCWKen, there's nothing wrong with the Kenbota! Looks good."

I agree. I'll bet you get quite a bit of use out of it? A co-worker has the RTV in camo. Uses the heck out of it hunting and around the farm.

wierdscience
07-19-2006, 07:30 PM
I've got a 3-cylinder waiting to become something.


KENBOTAPILLAR!......KENBOTAPILLAR!......KENBOTAPIL LAR!.....:D

CCWKen
07-19-2006, 08:29 PM
Ok, ok, ok! The 3-cylinder is reserved for the Kenbotapillar. :rolleyes: :D


How well does the bade work for you?

It works great now that there's more weight in front (FEL) and back (Liquid filled tires). If I could ever get the concrete wheel weights removed from their molds, I'd have more weight in the back too. :rolleyes:

It's a six? way blade. It angles horizontally and each side can be raised or lowered. I also have a tiller that mounts to the front PTO. ;)

old-biker-uk
07-20-2006, 03:49 PM
Check out the alt. I fitted to my Russian bike - might give you a couple ideas for fitting.
http://myweb.tiscali.co.uk/remark/pages/bikes/subpages/ural.html
Mark

x39
07-20-2006, 06:41 PM
Mark, nice job on the Ural. You've got me casting glances at the generator on my old Harley...

old-biker-uk
07-21-2006, 01:12 PM
X39 - I did think about it for my WLC but the 3-brush genny on it is pretty much bomb proof and I'm a great believer in 'If it ain't broke' etc. etc. wheras the original gen. on the Ural was about as dead as you can get.
Mark