Turning an alternator into a motor (while still being an alternator)

[jakobnev]

Heres the idea: If you make an AC motor controller and hook it up to feed the three phase coils in an alternator in phase(the brown bit is an angle sensor), the IC-controller in the alternator will decrease the field coil current because it sees the increased output voltage. At some point, as you increase the fed current, the EMF in the phase coils will be lower than the voltage you feed from the AC-MC and the current will reverse, and the "output"-torque of the alt will go from negative to positive, and viola, you have a motor!

And, you are, at the same time, providing the correct output voltage for the cars electrical system! Doing the same when the alt is not spinning would have to be done with the red and blue wire. (And the purple wire might have to be used to fool the car that the alt was working)

Since we didn't remove any components, only added some, putting the controller in high output impedance mode would cause the alternator to simply revert back to being an alternator. In fact, it can be done gradually, as the output of the controller is decreased, the alt just picks up the slack.

Regen could be done by drawing current from the red and blue wire, and boosting it up to plugin pack voltage. (Did i forget to mention there was a plugin pack from which all the energy came from?)

[Frank Lee]

How much power could it produce?

[jakobnev]

Well, if the series resistance is low enough to have, say, 80A @13v EMF and 1.5v over the resistance that gives us 1040W or 1.4hp.

[nimblemotors]

Alternators have very poor efficiency. You would be better off to replace
it with a better motor, a BLDC most likely.

Originally Posted by jakobnev

Heres the idea: If you make an AC motor controller and hook it up to feed the three phase coils in an alternator in phase(the brown bit is an angle sensor), the IC-controller in the alternator will decrease the field coil current because it sees the increased output voltage. At some point, as you increase the fed current, the EMF in the phase coils will be lower than the voltage you feed from the AC-MC and the current will reverse, and the "output"-torque of the alt will go from negative to positive, and viola, you have a motor!

And, you are, at the same time, providing the correct output voltage for the cars electrical system! Doing the same when the alt is not spinning would have to be done with the red and blue wire. (And the purple wire might have to be used to fool the car that the alt was working)

Since we didn't remove any components, only added some, putting the controller in high output impedance mode would cause the alternator to simply revert back to being an alternator. In fact, it can be done gradually, as the output of the controller is decreased, the alt just picks up the slack.

Regen could be done by drawing current from the red and blue wire, and boosting it up to plugin pack voltage. (Did i forget to mention there was a plugin pack from which all the energy came from?)

[justme1969]

very good! this is a great Idea, Ive long had this mod on my mind.
I learned this idea from install of toyota alt onto isuzu pickup.
Toy alt $65 isuzu $265 same size and bolt pattern diff plugs.
I rewired it wrong and caused it to run hot @ 18.5 volts. cooking my headlights one at a time and interior lights then battery.
I made it back and corrected it but wondered at the economy of a standard alt system. Thoughts and ideas reach to your post and beyond by adding a/c fan clutch and amp gage for battery v/s volt gages.
I have successfully married a toyota 85amp alt to replace my kia 45a alt then under driven it. Again u pull it $30 v/s $185 kia new one.
I wont be in this car for much longer so I can try new Ideas on it or sell it. Many small caterpillar powered trucks have GM style alternators that are just bigger than on old chevy cars and put out 150amps. mounting it and modifying its potential may even make more power than the stock engine does lol ok thats a stretch but it would be a noticable diff with kick in pants passing power to boot.
Add on a a/c clutch and deep cell batt. I would only need hit switch when I want mabe...

[rmay635703]

Originally Posted by nimblemotors

Alternators have very poor efficiency. You would be better off to replace
it with a better motor, a BLDC most likely.

As an alternator, yes they have poor efficiency due to the control circuitry bumping but as a motor with a decent controller, I have no idea.

[ConnClark]

The core problem with this idea is you need to drive it with enough voltage to over come the back EMF. You could reduce the coil current to lower the back EMF but then you would also reduce the power output of it in motor mode.

[night9]

Its been discussed before.

Plug-In Hybrid Retrofit Kit Using Alternator as Motor

http://ecomodder.com/forum/showthrea...tor-23884.html

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[Recumpence]

Hey Guys,

I hope I am not hijacking this thread by suggesting this, but;

I make high end electric drive systems for bicycles. The motors I use are 94% efficient at 3,000 watts or 90% efficient at 7,000 watts. I make toothed belt drive reduction units that use two motors. These reduction units have a freewheel on the output. So, if this were run to the engine's belt, the freewheel would allow the engine to drive without back driving the electric system, but the electric system could be run any time to add that 14,000 watts (actually 20,000 peak watts for 10 second bursts).

Something like this may be an easy (though not inexpensive) way to add some hybrid power.

Matt

[ECONORAM]

Originally Posted by jakobnev

Well, if the series resistance is low enough to have, say, 80A @13v EMF and 1.5v over the resistance that gives us 1040W or 1.4hp.

Originally Posted by nimblemotors

Alternators have very poor efficiency. You would be better off to replace
it with a better motor, a BLDC most likely.

True, it may not be super efficient, but it's a step in the right direction. I'd try it, but I'm not fully following the install...