I’ve done motor spreadsheets before, but now I’m considerably smarter. If you don’t believe me, just ask me. I’ll tell you. Honest I will.
Anyway, what with all this noise I’ve been making about dual motors and such, it’s come to my attention that it’s a pain in the butt to set up a dual PMDC motor array with a single controller in parallel. You, at the very least, need to have matched motors (which makes perfect sense, when you think about it), and then need to further tune them to keep them from burning themselves up. Running two controllers gets things a little easier to balance, but you still have to have the motors pulling the same, and now you’ve added another controller system, adding weight and more stuff.
So, this begs the question. What about just putting on a bigger motor, rather than doubling up a small motor? Which begs a spreadsheet.
Here are the motors I’m considering- the Motenergy ME1003, the ME0709, the ETEK, two ETEKs, and, just for yuks, that badass new AC motor that Zero has modified.
|Motor Type||Cont.||30 sec.||Voltage range||Amps Cont.||Amps Peak||Max RPM||Weight||Notes|
|ME1003||Brushed PMDC||11.5 KW||23 KW (1 min)||12 to 72 VDC||200||400 (1 min)||5000 @ 72V||39lbs||Radial air gap|
|ME0709||Brushed PMDC||6 KW||13.4 KW||12 to 72 VDC||125||300 (30 sec)||3200 @72V||36lbs||Radial air gap|
|ETEK||Brushed PMDC||7.2 KW||21.6 KW||72 VDC*||100||300 (30 sec)||5000 @ 74V||21lbs||Axial air gap|
|2x ETEK||Dual Brushed PMDC||14.4 KW||43.2 KW||72 VDC*||200||600 (30 sec)||5000 @ 74V||42lbs|
|Agni 95R||Brushed PMDC||12 KW||30 KW (1 min)||12 to 72 VDC||230||400 (1 min)||6000 @ 72V||24lbs||Axial air gap|
|2x Agni 95R||Dual Brushed PMDC||24 KW||60 KW (1 min)||12 to 72 VDC||460||800 (1 min)||6000 @ 72V||48lbs||Axial air gap|
|ME0913||3-phase PM Synchronous||12 KW||30 KW||0 to 96 VDC||125||420 (1 min)||5000 @ 96V||35lbs||Axial air gap, internal temp. sensor|
Huh. Interesting. At the published specs, the ETEKs don’t hold up. At these specs, they look pretty impressive… the million dollar question being, how long do they last at these loads? Wait. Sounds like we need to do a little blowing up of motors maybe. (Who says Mythbusters has the corner on the blowing up of stuff market?)
The ME1003 holds it’s own against the Agni, but at more weight (and half the price). The ETEK doesn’t hold up too well against the Agni, an interesting point, since the designs are so similar… so dual ETEKs ≠ dual Agnis. The solid ol’ ME0709 looks pretty conservative in this company.
(disclaimer: specs are the best I could find. If you have better ones and feel these are not accurate, feel free to comment with links. kthnx.)