PMA (Permanent Magnet Alternator) Generator Conversion

by relic Jun 4, 2018
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No power output .. yet. I think that my regulator or diodes are dead (most likely regulator). OR - I know some alternators need the output jumped to the Vsense pin to get Vout. May just solder directly to 2 coil wires & regulate externally.

does this turn it into a generator that is suitable for say wind power? what are the benefits of this conversion?

I'm still experimenting with it. Quite simply, I had a spare alternator from my WRX after upgrading the stock one. One advantage is that no excitation of the rotor coil is required, as is the case in standard alternators. Leaving the diodes intact should produce DC and bypassing them should generate 3-phase AC power.

I have mine assembled and everything fits very well, but I'm not getting any output yet. One or more of the internal diodes could be bad, or perhaps the built-in regulator. Next I plan to strip out those diodes and regulator leaving only the stator coils and see if that solves the problem. I can always rectify/regulate the AC externally.

Because of the strong magnetic attraction between the new permanent magnet rotor and stator, it does take a bit of torque to initially get it spinning. Once spinning though it's not as hard to maintain the rotation. So in a windmill setup you'd just need a good bit of torque, maybe a startup assist from a small motor and large capacitor. Such a startup mechanism could be isolated/removed once it is spinning. But, you might have sufficient torque to begin with. I'm using an old drill motor/gearbox to test mine on the bench using between 12 and 18 volts.

I would also encourage you to look into how a 3 or 4 wire, standard alternator works. There are plenty of diagrams and schematic online. I will post images of the rotor with magnets mounted soon ... hope this helps some !!!!

Another advantage - I've seen experiments with the diodes removed. With enough RPM I've seen 120 VAC to 240 VAC (or both at the same time) on the output. This was achieved by using the "2nd phase" coil winding as an AC center tap. A volt meter across the 'center tap' and one of the other windings gives you half of the total output potential while connecting the meter across the 1st and 3rd coil gives you the total output.

Another note: I may add another bearing and spacer to help keep the rotor aligned dead center soon ... we'll see if it is needed !!

thank you for the info