Build a very low speed DC generator

[the boulle]

re

I had thought of some thing for auto alternators

as you say the problem is the excitement

why not use the alternator (rewound) with a small dc motor (24v depending on the original engine, to easily output 12v in "dinamo") which would also be taken on the axis with a fairly high gear ratio ?! the faster your turns, the more its product, no problem of starting torque ....

what do you think?

[Other]

Hello

Everything is doable it depends on the time and energy you want to devote

excitement is not a problem
if you put permanent magnets for the excitation you no longer have the control for the regulation of the voltage according to RPM and load, although on a low power machine with large batteries in buffer it absorbs the load, it sells regulators that land on the load .. Some snowmobile or small engine have this box to regulate the voltage of the generator.

With full excitation, or permanent magnet the voltage depends on the RPM and the winding, (more turns, more voltage)

At the bottom RPM it takes a lot of poles
An auto alternator is precisely a generator that has a lot of poles, (on the auto it generates around 400hz)

Instead of redoing the simplest winding with an auto alternator, you get rid of the internal electronic regulator you feed directly full excitation the brushes an 8 to 10 volts DC (or 12volts with a resistance the rotor does not support 12 volts)

You disconnect the 3 stator phases which go to the diodes you leave the 3 external lines.
You plug in 2 on a transformer (an old battery charger we supply the 12 volt AC side and we collect on the other side a high AC voltage

Do all your tests by driving the alternator with a variable speed drill, make measurements .. according to the RPM
Attention attach the alternator in a vice even at 100rpm the force drill and you cannot hold it.

the only drawback for the handyman the usual transformers are single-phase while the alternator is three-phase, but it works quite well. Nothing prevents you from rectifying it with a diode bridge running it at the exit.

the good method (longer) is to place permanent magnets in the rotor for explanation and rewind the stator in single-phase with thinner wire but more turn.

Andre

[Alain G]

good evening, good night

I lost the thread a little!

As I have already mentioned on a few occasions when the alternator is excited once by a simple contact of 1 or 2 seconds between the excitation wire and the positive of the battery, afterwards it produces without stopping until 'it stops spinning simply because the magnetic field is self-sustaining in AC

I hope I don't have to repeat myself over 100 times! LOL

The transformer solution that André raises can also be considered, by excluding the regulator but with three transformers for the three phases or by connecting 3 capacitors to the diode bridges (voltage tripler) as mentioned in response to Christophe above. Christophe your 5-6 volts can give you 15-18 volts which with a charge will drop to 14-14.5 depending on the couple which will regulate by itself.

Rewinding an alternator is an unnecessary waste of time, anyway as Elephant mentioned and he is right, rewinding will not give more watts at output but will convert amps into voltage.

Please stop thinking about it and believe everything that is said on the web, several solutions are possible but not always the simplest.

You don't have to be afraid to put a strap on it for the tests and thus be able to use the best output rpm. To make complicated to have the maximum output is to give up after a certain time because you will not have the desired yield.

So make it simple and less effective but use 2, 3, 4 or even more for a total return that will make you smile because you will have the satisfaction of saying: it almost cost me nothing and I did not invest my family in the same time if the yield is not TOP.

An alternator taken for scrap costs almost nothing and that is recovery, anyway it will end up at the scrap yard. You do like me by asking for a model which surely will not sell, I got mine for 20 $ Cdn without taxes. We can also put several to provide more power.


Alain

[Christophe]

Well, you get as excited as you want . Normally the basic excitation is in DC and in series, but if you increase your voltage, you can decrease your current, the important thing is the amps all.

So if you have 6 volts now, if you have 40 X more turns, you can have 40 X more voltage and less current.

Ah no we do not excite as we want!

The important thing is the "useful" amps ... but according to the tests I have done with universal motors (built on the principle of assynchronous motors), well the excitation power can take proportions consequent!

The best was obtained at 2 volts DC with, at best, a ratio of 3.25 approximately, on the engine of my tests:



The engine had not undergone any transformation!

https://www.econologie.com/forums/moteur-uni ... t6819.html

[boubka]

universal motors (built on the principle of asynchronous motors)

[Christophe]

Follow the link: https://www.econologie.com/forums/moteur-uni ... t6819.html

It's explained"

[boubka]

no need to follow, if you want to compare a universal motor with an ac motor then it is a SYNCHRONOUS ring motor (WITHOUT MANIFOLD)

or reversible an alternator.

the only comparison that can be made with a universal motor is with a continuous motor.

[boubka]

small focus
synchronous motor = wound rotor with rings
asynchronous motor = squirrel cage
autosynchrome motor = magnetic squirrel cage or electronic management

[Christophe]

Not universal it is still different from autosynchronous: http://fr.wikipedia.org/wiki/Machine_%C3%A9lectrique

Universal = reversible direct current wound motor

[boubka]

no because they are very specific motor and I repeat it again there is no collector (rectifier)

an autosynchronous has absolutely nothing to do with a universal motor



no more than with an asynchronous