From what I've been able to research, temperature is a critical factor in the strength of plastic gears. They can handle a lot more when they're cold. Some of the heat comes from the motor and some is generated on the teeth by friction. A long hard climb can get them above the safe limit. Anything that reduces heating will help.robbie wrote: ↑Dec 31, 2017 2:22 pm
Setting my Phaserunner to a 50A phase current limit has had zero problems. It may be interesting to do some experiments to see if there's a significant gear strength reduction at higher temperatures.
Bafang rates this motor at "30Nm", which would translate to approximately 28A of phase current (simulator derived value), so I can see why 70A would have damaged the gears (http://www.bafang-e.com/en/components/c ... 1250d.html).
I run about 5A of fieldweakening current through my PR, and a speed limit of 40km/h on my CA3 with 30A/36V battery, most of the time I'm averaging around 30km/h here in Vancouver commuting.
Could you explain what's bad about the Q128H's eRPM?
BMSB also offer a 36V/260?
Which part(s) do you see as fragile?
The eRPM is too high for most controllers to handle. BMSBattery recommends one specific controller for the motor in their lineup, and refuse to sell a higher speed winding for this reason. The motor is crippled by design. They also removed all sorts of info on that motor off of their listing. The reduction being 16:1 is just from memory..
Not sure how you're getting that. I see 16 magnet sections, so divide that by 2 and you get 8. The MAC/BMC/eZee are all 16 pole motors.. 32 magnets divided by 2.From what I can make out it has 9 pole pairs rather than the 8 above; is that such a huge bad difference?
I don't see a Q128H with that RPM anywhere on their webpage. Do you?BMSB also offer a 36V/260?
I've seen plenty of complaints of clutch and gear issues with the Q100H and Q128H. Might want to read around about these motors if you want to find out more.
No surprise! if it took a super steep hill at ~1260W to make the gears look like the aftermath of a war zone, AND the stator/halls survived, i'd call that a testament to a motor of this size. I think it was right in thinking of it as a sleeper.robbie wrote: ↑Dec 31, 2017 2:22 pmI did have an experience where I damaged the gears on one of the motors, while I was late, I increased my phase current limit to 70A, and also removed my speed limit (36V battery, 35A battery current limit). Going up a steep (12% grade according to google maps) I blew the gears. I suspect I was sitting at around 80-90C (I had previously hit the thermal limit on my CA of 100C). I was traveling around 12-15km/h when it happened, so ~55-60A phase current.
neptronix wrote: ↑Dec 29, 2017 8:05 amebikes.ca seems to be the only vendor i can identify so far.
http://www.ebikes.ca/shop/electric-bicy ... 0-std.html
11 reduction x 8 poles x 540 rpm = 47520 eRPM.
I did search, rather extensively, but unearthed no Q100H users who damaged gears. However, a few Q100H "hot rodders" did report clutch failures. I did NOT research the Q128 so cannot comment on it.
The number of magnets to pole pairs on a 3 Phase motor...
You may come from a background with a different terminology, but I've never seen "poles" meaning anything other than "magnets" in a BLDC/PMSM motor. That's certainly the case for the vendors we typically use here, as well as PhaseRunner settings, Grin simulator settings, etc.Triketech wrote: ↑Jan 01, 2018 11:16 pmThe number of magnets to pole pairs on a 3 Phase motor...
When one pole pair is aligned directly with the magnet it switches to the next phase. Now if the number of magnets is divisible by the number of poles, the next phase is already aligned with the magnet. The field may rotate while it locks the rotor in place with the stator. To achieve motion between the stator and rotor, the succeeding phase pole needs the next magnet to be retarded.
And since there are 3 Phases the number of poles will be divisible by 3. Usually there are 2 more magnets than there are individual poles. That gives the shortest distance between "the next magnet" without confusing the rotor on which way to rotate during the moment of switching phases.
Apology for the confusion, its an old habit from back when I worked with induction motors. Stator Poles and Rotor Poles.cycborg wrote: ↑Jan 02, 2018 9:46 am
You may come from a background with a different terminology, but I've never seen "poles" meaning anything other than "magents" in a BLDC/PMSM motor. That's certainly the case for the vendors we typically use here, as well as PhaseRunner settings, Grin simulator settings, etc.