Author Topic: DIY Portable Generator  (Read 5569 times)

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Offline wilfor03

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DIY Portable Generator
« on: July 06, 2012, 06:41:11 am »
Was out watching the storms on the porch last night, and thinking? (Oh NO!!!!)

Has anyone built a small portable generator using B&S motor and an AC Servo motor w/rectifier yet?

I done some searching on Google, but not much luck yet. The B&S motors run around 3,000 rpm and that would put out

some pretty steady/good amps into a battery bank. Seems the servo motors could take the constant rpms with the bearing

they have. Pretty rugged little servos there.

Any comments/thoughts on this?

Just thinking.....

Bill

Offline WooferHound

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Re: DIY Portable Generator
« Reply #1 on: July 06, 2012, 10:15:12 am »
At that speed you could just use the alternator out of a car.
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Offline madlabs

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Re: DIY Portable Generator
« Reply #2 on: July 06, 2012, 10:24:06 am »
And if you use a high quality alternator like the Leece-neville 555 series they will last. I've got a lot of hours at max output on mine.

Jonathan
Some people are like a Slinky - not really good for anything, but you still can't help but smile when you shove them down the stairs.

Offline ksouers

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Re: DIY Portable Generator
« Reply #3 on: July 06, 2012, 12:47:35 pm »
Bill,
If you use a servo motor you won't have to turn anywhere near that fast and save a lot of gas. You will probably get by with less than 1000 RPM.
You are just charging up your bank, right?


Kevin
As far from the city as I can get but still keep my job.

Offline wilfor03

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Re: DIY Portable Generator
« Reply #4 on: July 06, 2012, 01:52:56 pm »
Hey guys.....

Thanks for the replies....

Kevin.....yeah, probably just above an idle. Haven't built anything yet, just thinkin about the "if" of the daydreams, ya know?

A man could use it for the battery bank at home, but I reckon I was thinking of a camping/hunting spot, more or less, cause

of the light weight it would have.

Might be interesting to just throw something together and see what shakes out of it, eh?

I have a small ac servo motor (400w) might have to sacrifice to the project.......

Bill

Offline ghurd

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Re: DIY Portable Generator
« Reply #5 on: July 08, 2012, 09:02:47 am »
For what it's worth,
My solder guy and myself have the parts rounded up, if that counts.

He picked up one of those HF coupon 3.0 or 3.5HP horizontal shaft for $60, just to have around as a spare.
Naturally, I had a 1HP GE ECM.
Picked up some pulleys to give a couple best guesses for the ratios.
Just need to get it bolted together for that end of it.

I designed a circuit to monitor the battery voltage (LM3914) and increase or decrease the RPM via a gear motor (All Electronics surplus windshield wiper motor, maybe for a Saturn?) and homebrew linear actuator (start with all-thread...).
Not fast regulation, but functional, cheap and easy.

Will probably end up with 2 phases reconfigured in 2 series coils, then the 3 pairs in parallel.
The 3rd phase with all 6 coils seperated and rectified individually.

If the battery is calling for enough amps to speed the motor up to a high RPM, the 3rd phase will cut in with a lot of amps.
Usually, after a short time of all 3 phases charging, I believe the battery bank will not need many amps to keep it at 14.4V, and the motor running slow with the 1st 2 phases charging will be more than enough.

Portable and quiet, mostly quiet, was what got me thinking about it.
Add a big inverter and a pair of golf cart batteries.
Can run circular saws, reciprocating saws, big drills, etc, with the gas motor basically idling.

Nothing I hate more than having a big loud-A$$ genny screaming 3600RPM so I can't hear myself think, just to power a circular saw long enough to cut a 2x4 once every 5 minutes.

I have some smaller PMAs here too, and I'd like to try a tiny version mostly as a house battery backup charger.  5 or 10A would be great.  Would be a good fit to a 4-cycle weed-wacker motor.
You see what a 4-cycle weed-wacker motor costs?   :o
G-

Offline oztules

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Re: DIY Portable Generator
« Reply #6 on: July 08, 2012, 05:43:09 pm »
My attempt was here..... works a treat.
http://www.anotherpower.com/board/index.php/topic,492.0.html#.T_oMi2BIeEo

..............oztules
Flinders Island...... Australia

Offline birdhouse

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Re: DIY Portable Generator
« Reply #7 on: July 08, 2012, 09:54:12 pm »
Quote
I have some smaller PMAs here too, and I'd like to try a tiny version mostly as a house battery backup charger.  5 or 10A would be great.  Would be a good fit to a 4-cycle weed-wacker motor.
You see what a 4-cycle weed-wacker motor costs? 

G-
i might be interested in the smaller version.  i know you mentioned 4 stroke weed wacker engines...  why not 2 stroke?  noise?  high rpms to get torque? 

only reason i ask, is ive got an old 2stroke chainsaw motor that is unused.  25cc.  made by john deer of all folks.  it's actually louder than my newer 60+cc stihl chainsaw, but that could be dialed with a muffler of sorts. 

eventually i'd like an auto start genset, but i feel like that's a ways off! 

adam

Offline wilfor03

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Re: DIY Portable Generator
« Reply #8 on: July 09, 2012, 07:40:24 am »
Go Mr. Ghurd, Oz, and all.....

I see I'm not the only "daydreamer" out there.

I've got to put that project on to #3, for now. Still trying different ways to whittle down those new blades for the ginny.

I've tried chainsaw, router, and getting ready to try a powered planner (if I can find a used one!)

Chainsaw is very fast once you get the correct jig made. But, its also the most dangerous of them all.


I have a 3.5 B&S vertical shaft motor to use on the "Port-A-Ginny" (catchy name, eh?) from a lawn mower. Got it to where it

will start on the 1st or second pull most of the time. Damn plastic carb on this one. Don't trust it for long, but, it will help me

get past the "testing" stage.

Oztules has a super nice ginny setup that I'll take some ideas from. Just want something that an ole man can throw in the back

of the truck without having to stop for a beer or two?

Hope everyone who's playing with these ideas/inventions will post their results/comments on the board to share with everyone.

To all.......stay cool in this heat, but have some fun.......

Bill

Offline ghurd

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Re: DIY Portable Generator
« Reply #9 on: July 11, 2012, 08:04:59 am »

i might be interested in the smaller version.  i know you mentioned 4 stroke weed wacker engines...  why not 2 stroke?  noise?  high rpms to get torque? 


Partly high RPM... calculate the pulley sizes for something like that.  Yikes.
Partly the PMAs too.  If reconfigured for high cutin RPM, then the motor would stall (I think).
Partly horrible fuel economy.
Partly engine life on any little 2-stroke I have access to.
Partly carb maintainence on any 2 stroke I ever had was a nightmare just because it didn't get used much, and the mini gas gennie would get used about that often.

Mostly scrapped the 2-stroke idea just from the pulley ratios.
Even McMaster-Carr doesn't carry a 48" dia pulley with a 5/16" bore.  ;D

One of the old neighbor guys gave me a Red (toro?) weedwacker... with electric start.
Uses a 6V SLA (3.5AH?). Dealer wanted like $80 for a new battery, so he bought a new wacker.
Was too late for me to get him a new battery at a decent cost, so he gave me the old one.
I gave it to the solder guy who's kids uses a lot of weedwackers at once, and they jump start it from 12V.
Besides, I don't want to deal with 2-stroke. (my electric one started every time for the last 17 years)

Anyway, considering how much more a 4-stroke wacker costs, the electric start option isn't that much more %?

If you want to get serious and small (and have some money to throw at it), the 2.5HP Honda is a dandy little motor.
G-