Quote:
Originally Posted by P-hack
Probably not, it is a bit nebulous. Admittedly I have focused on induction, and in DIY they are almost exclusively delta (i.e. HPEVS, reconfigures), pretty much make it reasonably symmetrical and you are golden.
BLDC might be an issue, pmac perhaps less, dunno, reluctance maybe less so. Lots of conflicting information out there. Minimize 3rd harmonics 
here is the ES take on magnet rotor delta
https://endless-sphere.com/forums/vi...4&hilit=+astro
"Astro's share poles and overlap.
That tends to be a problem when delta connected. The non-overlapping configuration is less likely to have circulating currents in delta"
one other thing to note is that the phases in the picture *look* like they are different lengths, i.e. one phase is at the root of the slot, another in the middle, another towards the rotor. But there are a number of delta pm motors in use. |
Thanks for the links & info.
It appears from the various links that one can expect about 3% losses due to the circulating currents. If it's a trapazoidal controller, things could be much worse due to the 3rd harmonics issue.
So, there's basically an engineering compromise decision at hand - whether to accept the 3% losses in exchange for a lower bus voltage. 3% doesn't sound like much, but it is 1.5kW
more losses at full power. To put this in perspective, my 2kW induction stove boils water pretty rapidly - like a "professional" gas stove.
With the MGR, the wires aren't brought out so setting it up for delta would involve messing with the internal windings. Even though I've completely disassembled one of my MGR's I haven't found the midpoint of the wye. I'm not saying it's impossible; just there's more work involved.
Because of similar extra costs and losses I decided to drop the booster idea. I figure I'll be just as dead if I touch 650VDC or 325VDC - but I guess that's a personal choice. If anyone is considering doing this
please please please do it with super-paranoid safety precautions.
- E*clipse