Actually car alternators are
producing basically first AC.
AC coming out the coils is
then put through a rectifier
and converted into DC.

You can get even 230 V AC out
of a normal car alternator,
if you will drive it
without any regulator.
The problem with this AC is
that the frequency is not suitable
for most normal appliances
built for grid electricity.

If you are planning to build
an engine generator
utilizing a car alternator
it is probably best
to use the generator
to charge batteries and
then use an inverter to run
the appliances.
Or you might build a 12 V
DC electric system.

1. Generator is probably a constant speed. It requires 16 HP so I doubt a human or for that matter wind will be of any value.
2. Car alternators are AC (hence the name alternator) Ac is converted internally to DC using diodes. I'm not sure what the frequency is of a car alternator at 2000 rpm or if it can be used for AC by bypassing the diodes. To convert from DC to AC you use an inverter.
3. If they have universal motors then they will work (drill, saw, etc.)
4. Bridge rectifiers are used to change AC to DC. Rectifiers use diodes. A single diode can have many uses. Usually used for blocking current from going bacwards. For instance, if you used a DC motor as a generator and it was hooked up directly to a battery once you stopped turning the generator the current would flow back into the generator and it now would be a motor and would turn. A diode can be placed in the circuit to prevent the current from flowing back, like a check valve.
5. There is no such thing as a dumb question!

Pick up your phone and dial 800-488-3407 and ask them to send you their free catalog. It's has alot of quality surplus DC motors and other items at a fraction the cost of other places. It's great for A.E. people. ( Alternative Energy )

Their web site is: www.surpluscenter.com

For a few dollars on a surplus dc motor you could run your cement mixer on 12vdc 24vdc or even 120vdc. A gas motor is still a viable option as mentinoed eairler.

Also often Ebay has excellent prices on DC motors. Try to stick to PM DC motors ( permanent magnet) are much more effecient then other typs of dc motors. A 24vdc pm motor will run just fine at 12vdc, but produce 1/2 the power.

Also spend a few $$ and subscribe to HomePower magazine : http:www.homepower.com  You can also for just a few dollars purchase all of their back issues on a CD. They contain tons of helpful info.

Also this Forum here is a true blessing with alot of good folks welling to help on it, as you are all ready finding out : )

In HomePower magazine there are several vendors that sell their large catalogs for $10 each or so. Not only do they have items for sale, but they also have alot of charts to help you plot what size system you should eventually have... such as a 12v system, 24v, 48v or higher. THIS IS CRITICAL !!!  AS I learned the hard way : (

Here's why.

You won't realize it at first, but whatever voltage you go with, If you are not careful.... you will slowly add items. Before you realize it, you'll have a fairly large investment in those items, and it will make it hard to change to a higher voltage because of your incurged high investment into all the lower voltage items that you have purchased.

There are alot of trade off's with different voltages. There are tons of items available for 12volts But when you start demanding more power... your battery cables finally grow to solid copper ones the size of a garden hose ! I'm running "0000" and this stuff is huge and expensive.

Moving upto 24v your wire size is reduced about 4 times in size, yet runs the same amount of energy down them. There's getting to be quite a bit of items that will run right off of 24vdc. Larger commercial 24vdc inverters are often actually less costly per output then their 12v counterparts.

48. volts is becoming popular with large systems. Voltages higher than this can be leathal if you come into contact with it. But 48 volts will usually just tingle, but not harm you. ( I say usually.. it still pays to practice saftey at 48v )
12. vdc to 48vdc are all dangerous as far as possible explosion or burns are concerned. A wrench accidently droped across the post of large battery banks can instanty turn them white hot... That's not good if you are still gripping it !

120 vdc is used in really large systems (usually commercial ), the voltage is very dangerous... and Inverers are ultra expensive.. usually starting out at $6,000.00 ( this is the current situational problem I'm trying to deal with.. I can't afford that.. and I really need one ) Advantages are, that most good commercial brush type power tools are rated right on their lable to run directly off of the 120vdc. Wire size is like normal house wiring and very convenient and nice to work with.

We built a new house on 120vdc. We built two large wood boxes with handles on the ends. Each box held six 12v deep cycle boat trolling batteries ( 60 volts per box )We rigged cables to plug both boxes togeather to produce 120vdc at the job site. We ran a table saw that had a brush motor on it, and all power tools. At night we brought them back to a power grid and re-charged them. It was nice quiet silent power. But doing this can kill the power switch on all of your tools, unless they are rated to run on 120vdc. DC arcs long distancs and will not eaisly break the arc like ac power does.

I also helped build a house using a one lung 16hp diesel ac generator... Trust me.. no one wants to go through the agony !!! Nothing like having it pounding away noisly all day long while you run a tiny jig saw ! haha

Bottom line... try to plan into the far future, how much power you hope to produce and use. Then plan your system to that voltage... this is especially critical concerning your appliances, and loads.

There is a electronic device known as a buck booster, and also special solid state switching power supples that are being discussed on this form, that might allow you to boost your low voltage wind machines upto a higher system voltage.

If you get time Rob, Email me... I'd be happy to discuss more... and I'd like to know more about your local... I bet you have alot more sun and wind then we do here. I'm living in S.W. Missoui.. and we really don't have much sun, or wind.. or hydro.. kind of a poor spot for A.E. as compaired to other areas..

Hope some of this helps...

 Can either an older type car generator or an alternator be used as a 12 motor for powering things like bycycles or cement mixers?

 I purchased a 16 page booklet titled "Alternator Secrets", mostly out of curiosity. One section I found interesting claims you can build a 120 volt, 60 cycle alternator by using an induction motor from a washing machine. You would have to run the motor faster than the nameplate rpm to get 60 cycles and you might have to hit the coils with a dc pulse to get it to start generating. This should produce enough power for anything from a tv to refrigerator. Not knowing that much about electric motors, etc, I would like to hear some opinions on this. It sounds to easy to be true.

As for my quest for a 12 volt cement mixer motor, I just ordered one from Surpluscenter for a very good price of $30. Now my problem is finding a pully to fit the 5/16 diam. shaft. Here are the specs: 12 volt DC, 3600 RPM, 29 amps, 250 watts (1/3 Hp). Duty cycle 30 on, 60 off. Reversible. Shaft 5/16" diam.x 1" w/flat. Four tapped face mounting holes. Size 4 1/4"diam.x 8". Shpg wt 12 lbs. What does that part about duty cycle mean?

Right now we are using manual power for the cement mixer. I took the side mount plastic handle from a 120 volt hand drill and bolted it to the large mixer drum
pulley. It is surprisingly easy to turn. Even with a full load, my 11 year old son says it is just boring rather than hard to turn. At least now we can actually see our progress unlike when we were using a hoe and plastic mixing tray.

If they haven't shipped that motor yet, I'd cancel the order right away if I were you.

That's a high-speed / low-torque motor, and you need somewhat the opposite.  I would imagine your original motor is 1725 rpm, and probably has a 5/8" shaft.  The 5/16" shaft on that DC motor tells me it isn't a high-torque machine.

The "duty cycle" means that the motor is NOT robust enough to run continuously.  It will burn up if asked to carry a load for too long a time.  The "30 on 60 off" means that you must shut it off before 30 minutes, AND let it sit a minimum of 60 minutes before using it again.  I would think that with a cement-mixer, you'd want something rated to run continuously.

The Briggs won't use any more gas than you'd use running your car engine to keep re-charging the batt, if using a 12vdc motor.  You'll also avoid having to buy a new batt in a week... <g>  (car batts are not made for discharge cycling).

For free-to-$30, you should be able to find an old rototiller and get a Briggs from it.  That'd allow you to:

• run as long as you want
• vary the speed of the mixer
• use the engine later for a genset, etc..

Genset from Induction Motor:  Yup, it works fine.  However, there is no way to regulate the output voltage except for varying the speed; so as you add load, you have to speed up the engine slightly, and your frequency will rise.  In the 3-5hp range, with a full load, you'll usually end up around 70hz. This won't bother anything....except clocks <g>.

As you remove load, the voltage will rise, and can get kind of high...130 or 140 volts...  Also, unless you've used a governed engine, the engine RPM will take off as the load's removed, causing the no-load gen. volts to go even higher.

You will need some AC-rated RUN capacitors.  Note:  RUN capacitors, NOT "start" capacitors !!!  The 'start' type will blow up after a few minutes of continuous usage.

I just uploaded a PDF file that I got off the web years ago.  You can go to my 'files' section of this forum and download it.  It has a wiring diagram and a graph for selecting capacitor values.  Gen-Induc.pdf

Note:  I have NOT verified any of his info.

Note:  If it was me, I'd use a 1750 rpm motor rather than a 3450 rpm motor.  With the Briggs running at 1800rpm, you'll get about half it's rated power....i.e. 2.5hp from a 5hp engine...but it'll use less gas per kw-hr and make a less grating noise.

I'd suggest spending some effort to locate a good junkyard, and make that your first stop, instead of harbor-freight.  Not a car-junkyard, but a real junkyard, with some of everything.  Some place that goes to the auctions when a big mill shuts down, etc. etc..  Such a yard is a GOLDMINE of equipment, parts, and materials !

At my local yard, I just picked up an alt/gen that looks like it was made for farm-usage, designed to mount in place of the regular alternator on an engine.  It's about a foot long and has BOTH a 45a/12v alt AND a 3kw 120vac 60hz genny built in.  Neat little electrical-machine.  Cost?  7 bucks!

Basically, a good yard of this type will sell you motors and xformers for just above copper-scrap price, which is around a buck a pound right now.  Saves them the trouble of tearing it apart to seperate out the copper.

In regards to running tools from an inverter, my experience has been that small angle-grinders and jigsaws run fine from a 1kw $249 inverter (i.e. Cobra et al); whereas a Skilsaw just slams it into shutdown <g>.  Oh, the big shop-vac runs fine on the 1kw too, but pushes the led-bargraph to the top.

We run our whole cabin from this type/size cheapy inverter, but I fire up a Monarch diesel-twin 5kw whenever I need to run the air-comp or the big 9" angle-grinder, etc..  I always try to time my work for when I'm going to charge the batt-bank anyway; which saves a lot of fuel and noise.