briogio said:
Hold on a sec. it's NOT a hub motor
It's quite clearly under the BB and uses the crank and chain to transmit power to the back wheel. It DOES use some form of phasing to "change" gears. Criticism's easy, Einstein was criticised, most innovators are; "Always look on the bright side of life". Now I'm as much of a retrogrouch as the next man but don't let it blind you to something innovative, however badly it's executed 8)
I didn't know there was more than one version; I just went by the video linked previously (and the posts/reviews I had read of it elsewhere, any of which even mentioned the motor itself said hub, most didn't mention it as far as type--I'm sure there are other posts/reviews of the other kind but I didn't see them).
Regarding the BB drive version, having now seen it, I can't tell anything from the info I found on the web here and there about it in the last few minutes. Their website has even less information.
My guess regarding "phasing" would be that they are using dual windings in that motor, and either running them in series vs parallel, or only using one set at a time, if they are doing it inside the motor. Crystalyte used to make a hub motor like this, and a dual controller for it. I never had the motor, so I don't know how well it worked (but I think one of the old analog controllers I have in a parts bin was for that motor).
Otherwise, I'd guess a gearbox on it's output that is shifted between two ratios, though this would not be "phasing" in any way I can imagine.
Phasing itself could just be a marketing term, but until I can see how they are doing it, I couldn't say whether or not it would work like they advertise it to work. There really are a lot of marketing gimmicks out there, calling an apple an orange, instead of just telling us if it's a Macintosh or a Granny Smith.
Still, based on reports of the problems of their other bike, and the reports like in that video (and a post here on ES by the same person) about not being able to get Busetti to honor their warranty, I wouldn't want to get one even if it was otherwise the perfect ebike design.
If they were to fix up all those problems and take care of the people with warranty issues (publicly), I'd reconsider that, but so far I don't trust them farther than I could throw one of the bikes. (I normally have a positive view of any new company, but this kind of thing turns that around fast, and makes it very hard to change my mind).
All that said, in your OP, the first question's answer is probably "no". I expect that what your'e referring to DB and others are talking about is the delta-wye switching, which has a specific ratio of change, which doesn't match any of the number claimed for this Busetti BB drive.
The other thing oft-referred to is multiple phase windings, using one set or another either by switching between them or by using multiple controllers, only one active at a time. That could give you any ratios you wanted, depending on the windings you choose, so that method could be what they used here.
But it basically "wastes" a lot of space in the motor that could be more efficiently used, by only using part of the copper-fill area for any particular set of windings. AFAIK, typically, you want to maximize the amount of copper fill around each stator tooth, for best power efficiency vs waste heat generation. If you use two independent windings instead of just one, only half (or less) of that space will now be filled with copper, as far as that particular winding, in use, will "see".
As I understand it, you don't really get "more" torque out of any particular winding by doing this, you just move the point on the motor's torque/power curve at which it still has high enough currents flowing to keep creating high torques, so that the motor's BEMF voltage won't approach the battery voltage even at the higher speeds up the hills, and so will keep trying to go faster and faster.
But doing that means also that the motor is going to get hotter a lot faster, with more current flowing thru it (and the controller and battery will also be pushed harder and the controller will get hotter), assuming that the controller itself does not have current-limiting.
