Alternator Motor Update
Posted by aonomus on September 20, 2009
So my last post about an alternator to brushless motor conversion seemed to draw some interest, but people were asking some details so I drew up a quick diagram in inkscape last night.
So again, essentially what I did to modify the alternator was:
- Remove the 3 phase rectifier module and voltage regulator module
- Connect the brushes to an external set of wires
- Connect the 3 phase windings to an external set of wires
Readers were also wondering how fast the motor was actually spinning as well. Since I don’t have a tachometer at the moment, I scoped one leg of the 3 phase windings (warning: because the 3 phase windings are floating, and the driver may push-pull, do not connect the ground of the scope to one of the 3 phase windings under any circumstance, only connect it to the electrical ground of the speed controller) and found at maximum speed with my power supply at its limit, there was 1ms on, 2 ms off of switching time, and I knew from counting turns that the stator had 12 electrical poles, thus 36ms per revolution, working out to 1620RPM. I need a bigger power supply, and a test stand with some sort of load to give it a real test…
So for now at least, a few interested parties have enough information to try this themselves. I do plan on developing this further and doing a full writeup with pictures and all, so stay tuned.