alternator power

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alternator power

Postby NICOBOTHA12345 on Wed May 27, 2009 1:33 pm

i am not very technically tought but power cuts and the billing figures are really getting to me, thus i have decided to try and generate alternative power.
i found an alternator of a car which generates on my volt meter 11.4 v (i take it that this is ac - as i measured the volts from the inside of the alternator, there are 3 fairly thick wires)

the general idea is to power the alternator with wind and a 5 or even 10 to 1 gear ratio (the blades would be mounted on a big wheel connected by chain or fan belt to a small wheel on the alternator), in times of no wind the alternator will be powered by a solar panel.

i need to power 1) geyser 2) airconditioner 3) 3 x 250 watt security lights 4) house hold lights

so in my ignorance i have devised a few plans to accomplish this

plan 1

is to utilise the alternator volts via a 20 to 1 step up transformer to give me 228 vac ? (alternator will always be spinning as long as i have wind or sun)

plan 2

to use the dc volt of the alternator (i believe only 12vdc) to charge enough batteries then convert the dc back to ac to give 220 vac power.

plan 3

a welder utilises alot of power and i have heard that there are guys that have converted an alternator to produce enough power to run a welder, this for me would also be sufficient, but as i mentioned i am not very technical, but even with just this idea i was thinking that if one alternator can power 1 welder = geyser, the more things i want to power i just need to add additional alternator power stations.
would any of these two plans work?

regards

nic
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Re: alternator power

Postby windgat on Wed May 27, 2009 6:50 pm

Something strange about getting only 11.4V - maybe its not spinning fast enough?

:?: Why use solar PV to turn the alternator :?: More efficient to use the power from the PV directly.

Alternator with a pulley as you describe can work. Of course you lose some power via the pulleys and chain/belt.

How many watts are you looking at producing? A geyser is a power-hungry animal... you may need massive blades to make it practical.

You can charge batteries from the alternator (via a few diodes or a rectifier), and then use and inverter to get AC - that is the usual kind of setup.
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Re: alternator power

Postby Greystoke on Thu May 28, 2009 7:05 am

NICOBOTHA12345 wrote:plan 1

is to utilise the alternator volts via a 20 to 1 step up transformer to give me 228 vac ? (alternator will always be spinning as long as i have wind or sun)

plan 2

to use the dc volt of the alternator (i believe only 12vdc) to charge enough batteries then convert the dc back to ac to give 220 vac power.

plan 3

a welder utilises alot of power and i have heard that there are guys that have converted an alternator to produce enough power to run a welder, this for me would also be sufficient, but as i mentioned i am not very technical, but even with just this idea i was thinking that if one alternator can power 1 welder = geyser, the more things i want to power i just need to add additional alternator power stations.
would any of these two plans work?

regards

nic

Plan1: I wouldn't try this. Step-up transformers are designed to operate @ mains frequencies (=50 Herz). The transformers will burn out if the alternator is not spinning fast enough.

Plan2: That's the kiddy IMO. You need an inverter to transform the 12VDC to 240VAC.
Inverters are coming at lower prices these days. I saw a 1kW unit (modified sinewave) for R1500 at Builders Express.

Plan3: Yes, A big(ish) alternator can produce in excess of 30 Amp, which is enough to do light welding, but you need to spin the alternator at ± 2000rpm. For that you need a DC-motor.
Regards
Cor
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Re: alternator power

Postby Fritz on Sun Jun 21, 2009 10:21 pm

Hi guys, I am also interested in using a car alternator as a wind generator, as I don't have spare time to make a gen myself.
However, I have no idea how to make the blades and how big. Can anyone help?
It is for a friend who runs a few lights and TV from a deep cycle 40Ah battery until it is flat. He then charges it with his car idling.
It should be able to charge the batt in 24 hours in a 10-15 km/h wind.
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Re: alternator power

Postby windgat on Mon Jun 22, 2009 12:10 am

40Ah in 24 hours = about 2amps continuous, which is about 25 watts

Lets take a 1m radius blade, and work with max possible power.
10km/h = 2.7m/s max power 21Watts
15km/h = 4.2ms max power 82 Watts

So wind speed is critical.

Since you will lose power by gearing up with a pulley (or a chain or a gear) maybe aim for 1.2m radius and you should be in the ball park.
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Re: alternator power

Postby basiedp on Wed Aug 05, 2009 7:16 pm

Alternator use in a wind system has a view issues, high rpm needed. The freq changes as the speed does. Don't use the ac side as you will cry later. The tests that was done using altenators has resulted as follows, you have to replace the rotor with an alu metal and fit magnets all around then play with the windings. Possible rewind to get the desired volts at a given rpm.
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Re: alternator power

Postby prakash on Wed Oct 28, 2009 1:27 pm

hi...
you want to convert a alternator into windmill ? sure u r thinking right but ther are some problem due to high rpm,you can solve this matter,contact me via mail
but the idea is not free you have to pay.if you intersted contact me my Email-ashakily@gmail.com
prb
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Re: alternator power

Postby basit on Tue Nov 11, 2014 8:22 am

how can we use solar panel in town or village if we have lack of recourse....now days we are use water as a power in our town.



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