# AC to DC conversion project

#### frisbee4all

Joined Feb 22, 2009
13
Hey guys,

I am a mechanical engineer working on a senior design project. Basically, I need to take a varying input from an AC generator/motor/alternator and convert it into a smooth DC operation. So far I have read up to the diodes/rectifiers but I'm still not sure 100% where to go from there. Also, does anyone know if there are equations that relate the input rpm of a motor to its output voltage? Thanks

#### beenthere

Joined Apr 20, 2004
15,808
The RPM relates to output frequency. The output of a coil relates to the number of turns in the coil and the number of lines of magnetic force cutting across it.

Her is a link to the Wikipedia article - http://en.wikipedia.org/wiki/Electrical_generator.

Any physics text treats on the subject.

#### frisbee4all

Joined Feb 22, 2009
13
Thanks guys, thats pretty much where I'm at right now I'm just trying to get rid of those ripples caused by the capacitor. Any one know how a voltage regulator works or which one to use, equations are preferable. Another thing that I'm having a problem obtaining is the actual output equations of the generator. Do the generators have an AC-DC converting circuit built into it? Or would I need to add a rectifier circuit after it?

#### bertus

Joined Apr 5, 2008
19,934

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#### frisbee4all

Joined Feb 22, 2009
13
Thank Bertus, that pdf file was exactly what I was looking for, it took me about 3 books to get what that file said, plus the file simplified the voltage regulator step. I appreciate your guys help!

#### rajeshbro

Joined Feb 8, 2009
9
You will need a rectifier ( full bridge) to convert AC to DC then Smoother to smooth out pulsing DC ouput from the rectifier, then a chopper to make output voltage from the smoother into a constant voltage output. That pdf attached by bertus is pretty good. Kudos to him.