Author Topic: alternator generator  (Read 6404 times)

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EEstudent

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alternator generator
« on: June 08, 2010, 07:07:45 PM »
Hi,

I decided just for kicks to see how much power I could get out of an alternator using a bike to power it. I know the alternator is horribly inefficient and this is not the best way to try and produce power. But i still thought I'd try it out and see what I could get. attached is my wiring diagram, could anyone please comment on if it is correct or not? I understand that the sense wire runs to the b+ output on the alternator, and that the green wire that comes out of the alternator clip needs to go to ignition in a car or some way to excite it so i put that on a switch with a battery at the other end. and then for ground i am using the alternator frame.When I am pedaling at about 2000 rpm i only get out about 80 mA and about .4 V out of the alternator. I thought 2000 rpm would be enough to get some current out of this thing because when your car is on it is not always above 2000 rpm and at that rpm the alternator is running just fine in a car. i don't expect to get nearly the same amount of current out of it. And i assume the alternator is turning at about 2000 rpm because for each turn of the crank shaft the alternator turns about 22 times. so when i am pedaling at 100 rpm that should mean the alternator is turning at about 2000 rpm. Anyone have any possible suggestions of what I am doing wrong?

Thank you
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« Last Edit: June 14, 2010, 05:55:54 PM by kurt »

bob g

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Re: alternator generator
« Reply #1 on: June 08, 2010, 07:49:50 PM »
what make, model etc of alternator are you using?

that would really help knowing.

bob g
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large frame automotive alternators for high output/high efficiency project X alternator for 24, 48 and higher voltages, and related cogen components.
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Rover

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Re: alternator generator
« Reply #3 on: June 09, 2010, 06:30:29 AM »
What is the load that is in series? with the Alt?
Rover
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EEstudent

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Re: alternator generator
« Reply #4 on: June 09, 2010, 01:17:51 PM »
the load is just a couple of 12v light bulbs, I am just trying to test the output power currently.

willib

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Re: alternator generator
« Reply #5 on: June 14, 2010, 01:29:12 AM »
EEstudent , i'm not entirely sure that the alternator in question is a 'one wire' , not because i've never heard of one.. (no pun intended)

but Because the way an alternator works..

a automotive alternator has to have a field current flowing to get power out of it..

that would require at least three connections.

one would be the power out of the alternator

the other would be the power into the field winding.

the third would be the ground which is the case of the alt itself..

 i think you are missing the field winding connection?

as a side note , if you vary the field winding current you will be able to adjust the power out of the alternator. And consequently the power you have to put into it, the pedal power.
Carpe Ventum (Seize the Wind)

ghurd

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Re: alternator generator
« Reply #6 on: June 14, 2010, 02:30:32 AM »
A couple things- including the wiring diagram.

"One Wire Alternators" are often called 'marine alternators' and they often really do only have one wire.

The power out to the battery,
and in to the field from the battery are combined.
The ground is the frame, so no wire.
Total is 1 wire.

I can imagine some advantages to a One Wire alternator, under some circumstances.
If the run from a small engine driven alt to the battery is long, the voltage drop in the wire would be sort of a self-adjusting field idea.  Sort of a tapered charging amps?
The big issue for me is the cost. 
The last one-wire alt I installed was a rebuilt Delco, and it cost him $300 ($300 24V rebuilt 1-wire Delco is all I can recall).


The real issue is the wiring diagram.
It is bad.

The Load, Battery, and Alternator are all 3 in series.
The Load would be carrying the battery charging amps.
The voltage regulator would be seeing the battery voltage and the voltage drop of the load.
Eventually, the battery would be up to regulation voltage and the load would see 'almost 0A', no matter how much power/RPM was put to the alternator.
It is a self defeating schematic.

G-
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willib

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Not grounded
« Reply #7 on: June 14, 2010, 03:48:16 AM »
I would have to agree with ghurd.

Your diagram is not using the alternator as a ground..

If i have this correct , you should connect the case of the alt , to the battery negative .
then connect the B+ to the battery positive.

Your sense wire , ahem, is then connected to the battery Positive.

Since i don't have a schematic of the alternator , i have no clue what the green wire , is for .

ditto on the brown wire .

I did some searching on the net and discovered that the slightest drop in voltage , as might be caused by switching on a light bulb , actually turns on  the regulator .

So i would try just connecting the case and battery negative, B+ and the sense wire to battery positive , start pedaling and connect a light bulb across the battery .

Happy pedaling.


Carpe Ventum (Seize the Wind)