how many rpm's does an alternator need to turn to put out a good volt/amperage? my little drill can only turn 1400 and was only getting .25 volts...

 

I dont know the exact number but it needs to turn more then that. alt. rpm is alot more then engine rpm. you have to do math with the pulley diameters to figure out the idle speed of the alt.

 

duh, thanks, i didnt think about that, TY

 

Usually 2-3 times the speed of the engine, so you're looking at at least 1500 rpms at low idle. By the way, the alternator needs to be "started" by applying 12V on one of its terminals, unless it's self-exciting model which your factory unit isn't.

 

this isnt for this truck, its for a project i am working on, i would like to find a 1 wire, but i dont know what models would have that. though i did find the farmula for figuring the rpm needed, kinda easy onve ya know what it is...

 

The formula for the RPMs has to do with pulley diameters - take the ratio of the crank pulley diameter to the alternator pulley diameter (usually between 2.5 and 3, but sometimes more), then multiply that by engine speed. In other words: "crank pulley diameter" x "engine RPMs" / "alternator pulley diameter" = "alternator RPMs".

AFAIK there is n 1-wire alternator installed in any vehicle, so your only hope of finding one in the junkyard would be from a truck (usually a Chev) that had a different engine transplanted in it and the owner didn't feel like messing with factory wiring for it. Other than that you're pretty much outta luck. Use a Ford alternator tho, preferably a 3G, then I can tell ya how to wire it up easy. Are you using this to charge up a battery?

 

yea, its going to be set up to charge a battery. i have one for my blown geo motor that is a 55amp which is plenty for what i need. i know it has the bolt post and 2 wires that go on the back...

 

There ya go man, explanations on wiring a GM alternator: Hooking Up Your Electrical Connections For The Alternator
And here is the diagram you need:

 

Thanks M... one Q about it, the power supplies through the o/f switch, is where the power come in to start the generating of the alternator? from what i have read the alt needs a short charge to jumpstart it, so once it is running, energize that one for a few seconds to engauge?

 

In a vehicle that's a key-on wire, so in your application you should keep the switch engaged as long as you want the alternator charging - when you're done charging and shut off the alternator drive (whatever that may be), trip the switch to off so whatever field it is inside it that gets excited by that terminal stops getting excited and don't drain your battery overnight.

 

Check out the bottom of the page on this link.

More Home made generator projects!

They have a diagram for all three types of alternators.



For a small system you might want to consider these.

Harbor Freight Tools - Quality Tools at the Lowest Prices


Couple 12 volt batteries and LED lights in various locations around the house.....

 

what i am looking at being able to do is ultimately piggyback 2 inverters to run some 240 applications, if what i am thinking works... my scape goat will be the swimming pool pump, something small, and cheap and easily replaceable when i blow the poor sob up.


10-4 M. what i am planning will be a 24-7 run for a durrability test/

 

I don't think you can piggyback two inverters for 240 V operation (unless you can find two that have a cross-connection to keep them phased correctly). In order to obtain 240 V, the inverters would have to be phased correctly, and if not cross connected, phasing will be random. In fact, if the frequency isn't spot on, they will drift slowly in and out of phase, and your 240 will go from 0 to 240 and back.
If, however, your "240V load" is actually two separate 120 V loads with a common neutral, you could make it work. Now, even if you do manage to get 240 volts off a set of inverters, the battery draw is going to run quite high. Lets say your pool motor draws 7 amps running. 7 X 220 = 1540 watts. 1540 /12 =128 amps. With conversion losses, about 150 amps would be needed from a 12 volt battery. And we haven't even discussed startup draw on your pool motor which can be several times the running current. So now you're looking at 400-500 amps or more out of the batteries, and inverters that can handle the surge.

“Will those who are dismantling this society from within or those who seek to destroy us from without be the first to achieve their goal? It is too close to call.” - Thomas Sowell

 

most inverters are able to run piggyback, and the pool is 2.2 amp 120v so it wont the the unlucky one who gets the 240. the 240 will be 2 true sine units, not a square unit set

 

I did a search on solar panels, and found 240 volt inverters on the site.

When you are calculating loads, you always use 230 volts as the required voltage on single phase current.
So that running load jumps to 1610 watts or 134 amps at 12 volts.

Now consider a glow plug system draws 200 amps and the starter motors draw 300 amps on the IDI diesel.
So with a bank of batteries, the load is not out of the question.
The inverter that can start a motor drawing 1600 watts running may be another issue though without laying out big bucks for it.
3 to 5 times running amps for the start load on motors.