U V W phase and hall references in diagrams

[wallypedal]

I continue to work and learn on my son's bike setup. After going through the 36 possibilities testing for phase/hall combinations I'm satisfied we have the best one. Nevertheless, I have never understood the schematic or table instructions that specify things like "Blue --> U; Green --> V; Yellow -- W" What are the U V W references for? They are commonly listed with a different color/letter combo for the halls vs. the phase. My thought is it must be some sort of sequencing thing, but I just don't know. Can someone explain?
Wallypedal

 

[amberwolf]

U V W are a common set of letters to refer to three phases for such motors.

Some controllers actually have their phases labelled as such on the PCB. They may also have their halls labelled this way, but at least some of the ones I've opened up that use UVW on the phases, use only 123 or ABC on the halls, and the pads don't necessarily correspond in the same order as the phases.

Sometimes the motor may *also* be labelled inside with UVW on either halls or phases or both, but most commonly has no labels at all inside it.

If both controller and motor do label both halls and phases as UVW then you could simply wire directly from U phase on motor to U phase on controller, etc., and U hall on motor to U hall on controller, and it would jsut work.

But since it's atypical to find the labelling at all, much less as UVW, you usually have to determine the phase/hall combo in other ways.


FWIW, there is no need to use 36 combos, 99.9999% of the time. Do this:
http://endless-sphere.com/w/index.php/Determining_the_Wiring_for_a_Brushless_Motor
and it will work for just about every circumstance.

 

[wallypedal]

Thanks Amberwolf!
What I don't understand about the colored chart is that it appears to assume that a good combo will be found without ever changing sensor wires - always green>green;blue>blue;yellow>yellow. Perhaps this is almost always true, and the three decent combos will emerge by using only the upper part of the chart. I think our best combination came with sensor wires not matching. I will review my spreadsheet, but do wonder why the chart is built that way. It does sound like the UVW stuff is just sequencing then. I will keep researching, too.
Wallypedal

 

[amberwolf]

It's not uncommon to find the best combo with *no* wires matching; wire color is completely arbitrary and has virtually nothing to do with what actually goes to what, unless you happen to have a kit that all was wired up by the same person or factory, designed to be hooked up color to color.

Unfortunatley even stuff in a kit all from the same seller does not guarantee it is all going to hook up color to color, and I would guess that it is more common for it to *not* be color to color.

As for how a particular motor / contorller combo works up vs the chart, I don't know. I don't use a chart, I just use the text method posted by John in CR that's in that article. Until he posted that, I did use a 36-combo chart, but once he posted that I realized it was completely unnecessary, and almost always I find the right combo with just moving phase wires around, after I've hooked up the halls in some single order. It might take 6 tries, but it doesnt' usually take more than 3-4. The most it took was 8 (there are 8 possible combos of the three phases) to get one that worked right.

Once, that combo was in the wrong direction on a geared motor (which cna't be flipped around in the dropouts), so I also had ot use the hall switching part, but the rest of the time I just flipped the wheel around *or* used the reversing wires on teh controller. (some have that, some don't, and some reverse modes give less power than forward, so that may not be possible for everyone to do).