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Bump... I would like to do the same thing.
is it as simple as finding an AC speed controller and connecting the right wires or does the unit itself need to be wired for DC?
 

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is it as simple as finding an AC speed controller and connecting the right wires or does the unit itself need to be wired for DC?
There's not way to "wire it for DC", because it doesn't have a commutator; you would need a suitable controller-inverter.
 

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There's not way to "wire it for DC", because it doesn't have a commutator; you would need a suitable controller-inverter.
Thanks for chiming in.. maybe I was confusing 3 phase to 2 phase ac/dc ? IDK what i'm talking about.. I play with things until they break or catch fire and I get hurt. What I'm trying to ask you is if there is any modification necessary to turn this type of generator into an electric motor? I know some car alternators have a 12v line running to them to create the electric field for charging and the - commutator - would be the rectifier switching the AC out to DC out... is it as simple as running it backwards and pushing energy into it with some sorta suitable controller?

It would appear to me (i dont know shit btw) that the rotor would either need to be modified or provisions made to excite that field.

seriously thanks;

it would be much appreciated if you could just tell me how this would be feasible or if it would even be worth the trouble. what kinda values could this theoretically produce? does the power rating/consumption stay the same like 6500watts for example. honestly I don't expect you to reply.. i know i sound like a child :)
 

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There's a start.

In a simple explanation, an alternator can be turned into a 3 phase AC motor. You need a suitable controller to do that. you can get them off ebay for a good price, Just look for something suited to an ebike or similar sized motor. As it stands though, they don't make very good motors, as there is no way for the controller to 'know' where the rotor is in its phase cycle. you can fix that by installing 3 hall sensors into the stator, to detect the rotor.
That is a good little project that'll teach you about 3 phase motor basics, but there is still a bit of a learning curve in figuring out where to put the hall sensors, how to wire them, what order they go in etc.
You also need to feed power to the rotor, via the slip rings and a modified/gutted regulator. Its not as simple as just feeding it 12v either, while that will work, there is a lot of tuning to get the voltage just right, which also varies depending on the rotor speed.

If your not afraid of a bit of tinkering, circuitry and theory, then jump right into it. If your expecting it to be a really simple hand held excersize, probably stop now and just buy a proper designed motor.
 

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... maybe I was confusing 3 phase to 2 phase ac/dc ? IDK what i'm talking about.. I play with things until they break or catch fire and I get hurt.
2-phase power is very rarely used; when people say "2-phase" they usually mean split single-phase (such as the 240/120 volt service found in North American homes). But whether the alternator is for single-phase or three-phase power doesn't change the situation fundamentally.

What I'm trying to ask you is if there is any modification necessary to turn this type of generator into an electric motor?
What's "this type"? In the original post of this thread an alternator from a generator set was shown which is significantly different in details from the alternators typically used in vehicles to supply 12-volt power. TeZla's post is about automotive alternators, not that one from a genset.

I know some car alternators have a 12v line running to them to create the electric field for charging and the - commutator - would be the rectifier switching the AC out to DC out... is it as simple as running it backwards and pushing energy into it with some sorta suitable controller?

It would appear to me (i dont know shit btw) that the rotor would either need to be modified or provisions made to excite that field.
Those are two good observations: the wound rotor needs excitation (whether the machine is operating as a generator (alternator) or as a motor) and something needs to convert between AC and DC (which is done by a commutator in a DC motor, but there's no commutator in an alternator).

In the alternator of the generator set shown, the AC is output is used directly so there is nothing converting it, and the machine could probably be driven without modification by a suitable inverter; there is presumably a rectifier internally to produce the DC power needed for the rotor.

In automotive alternators, AC power output is not wanted so they include a rectifier, which needs to be removed (as TeZla mentioned) so the individual phase windings of the stator (normally three phases) can be driven by an inverter. The DC power supply to the rotor (through slip rings) could be left simply connected to 12 volts or varied by another controller for efficiency.

I don't see any reason to modify the rotor, in any case.

it would be much appreciated if you could just tell me how this would be feasible or if it would even be worth the trouble. what kinda values could this theoretically produce? does the power rating/consumption stay the same like 6500watts for example.
The power capability would be roughly similar in motor mode to what it was in generator mode, and that's one reason that this sort of conversion usually doesn't make practical sense: the result is not likely to be powerful enough to be useful, which is why the examples are for bicycles and small carts.
 
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