Altermotor: Alternator to BLDC (PMSM) Motor Conversion

Want an electric gokart motor, but don't have $500+, and all you have is an old, busted alternator taking up space in the garage? Well, I have news for you!

Take that chunk of automotive/E-waste and turn it (and about $60 worth of parts and magnets) into a sweet, powerful electric motor! Watch my YouTube vids for more

Background:

I wanted to electrify some projects and didn't want to spend hundreds of dollars on electric motors. So I designed my own solution (under my own volition, I'm not saying I invented this method) to the afore mentioned dilemma.  

I picked up some old (new and used) alternators on marketplace and craigslist, dismantled them to see what I can use, then fired up Solidworks to design a permanent magnet rotor core. 

Why didn't I just use the alternator backwards? 

• I did at first, actually! In order to do so, I removed the rectifying diode packs, and left the brushes in and stator winding ends sticking out. I then attached a 12V power source to the brushes to activate the electromagnetic rotor core, and a BLDC controller to the stator windings. Even at full bore, I could stop it with my hands (using a 3S LiPo for power). So I designed a core based on materials I can get from McMaster Carr and Amazon, tested it again and was surprised at the results. I couldn't stop the shaft with my hands! This thing had speed and power! 

Well, fast forward 1 year and 4 more altermotor builds later, and I used a big one on an electric motor driven cycle project, my Electric Mini Chopper. Check my U-Toobs for a glimpse. 

Now I am honing the core design to give higher torque, lower cogging torque, and higher efficiency (implied by the first two). I am diving into motor design and finding out the best solution to use with these alternator stators.

My Altermotors:

AC Delco 106mm is in the mini chopper altermotor

AC Delco 88mm is a test bed for core magnet topologies and has hall effect sensors

• This stator has sinusoidal windings, with a coil gap of 3, 36 slots, and is in a Wye configuration.

The remaining 3 are Bosch altermotors with differing core diameters. 

• One has decoupled phase ends, so I can use it in Wye and Delta configurations
• Two are dual 3-phase, which I am pondering the use case for, outside of power generation. You can run each of the 3-phase groups separately, but can't couple or bridge them together, so you end up not using half the copper as a motor. As generators, the 60 degree phase shift between each group allows for a smoother voltage ripple once rectified.