My1020 / Kunray / YaLU 1000 - 2000W motor ?

qwerkus

10 kW
Joined
Jul 22, 2017
Messages
785
Does anyone own one of those MY1020 / Kunray / Yalu or whatever motor they are called:

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Super cheap and readily available. They seem to come in 2 versions: a 124mm 1000W and a 134mm 2000W. Both 107mm diameter. Weight is somewhere between 3.5 and 4kg. A version with a 4-bolts foot is also available.

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My question is: are they usable ? Seem like an inrunner, and would love to seem more of the internals, if anyone has pics. Speed probably a bit high for bike use - better for karts or other EVs with small wheels. Maybe a WYE / Delta hack to make them more suitable for ebike use. Or plain rewind.
 
Low power to weight ratio on those babies.
Probably not great efficiency.

Of course they're cheap.

with dimensions like that, they'd be my last choice, as you'd instantly get a weight imbalance no matter where/how you mounted the motor.
 
This is 2019, why do we still not have small, lightweight, high power mid drives readily available? Reduction of course. Only reduction worth a shit is the Tangent's and it's loud.

Rewind to change kv is COMPLETELY different from reduction and won't increase torque unless you put in more copper. Rewind / gearing down are not interchangeable in the slightest.
 
Running one of these on a Razor kid's toy operating at 60V nominal and around 150-160 phase amps and around 120 battery amps. Cheap, relatively heavy, but not bad! We've beat and beat on it and gotten it quite hot (boiling water) with no noticeable degradation to the enamel. I am pretty sure it can do 200A peaks for several seconds though I have not pushed it that far, yet. The build quality is not amazing, but not bad.

The magnets are mechanically retained by a laminated rotor core and are also glued. They are very thin, however, and I had one let go when running under no load with FW. I was not datalogging unfortunately, but I think it was around 8000-8500rpm. I think wrapping the rotor with kevlar and rebalancing could yield some great results. As of now, we're keeping it below 7500rpm and are getting somewhere around 7.5kW out, peak. That's with calculating motor efficiency, not measuring, though.
 
coleasterling said:
Running one of these on a Razor kid's toy operating at 60V nominal and around 150-160 phase amps and around 120 battery amps. Cheap, relatively heavy, but not bad! We've beat and beat on it and gotten it quite hot (boiling water) with no noticeable degradation to the enamel. I am pretty sure it can do 200A peaks for several seconds though I have not pushed it that far, yet. The build quality is not amazing, but not bad.

The magnets are mechanically retained by a laminated rotor core and are also glued. They are very thin, however, and I had one let go when running under no load with FW. I was not datalogging unfortunately, but I think it was around 8000-8500rpm. I think wrapping the rotor with kevlar and rebalancing could yield some great results. As of now, we're keeping it below 7500rpm and are getting somewhere around 7.5kW out, peak. That's with calculating motor efficiency, not measuring, though.

Interesting feedback. Do you happen to have some pictures ? 7500RPM is alot though :shock: I'd need to halve it at least to get something useful. That's why I was talking WYE/Delta hack or rewind; not to get more power per weight, but better efficiency at 14s and a medium reduction. Currently looking for the biggest motor I could squeeze into my frame, and this one, together with a 1:10 reduction could be a suitable candidate. But a 24V system with super big wires / controller for high amps just won't do it. Also, I'd have to trim the 124mm version to 100-110 max - hence the wish to see what's inside.
 
flat tire said:
This is 2019, why do we still not have small, lightweight, high power mid drives readily available? Reduction of course. Only reduction worth a shit is the Tangent's and it's loud.

There are a bunch of small, lightweight, high power mid drives on the market. IMHO they are all loud as hell.
Those drives also tend to use trapezoidal drives or the wrong kind of gears for keeping things quiet.
It's really unfortunate.

IMHO it seems like the focus on commercial bikes with proprietary bits galore has sucked the life out of DIY kits. The only thing i find exciting these days is the CYC X1 pro 3kw and the dual reduction geared hubs.

There is certainly a big gap in the 2-3kw chain drive motor space. Lots of motors out there with crappy 0.5mm lams and ~85% efficiency, where another ten or twenty bucks for thinner lams could get you into the low-mid 90% and dramatically higher power output from the same copper, magnet, and iron mass..
 
neptronix said:
here is certainly a big gap in the 2-3kw chain drive motor space. Lots of motors out there with crappy 0.5mm lams and ~85% efficiency, where another ten or twenty bucks for thinner lams could get you into the low-mid 90% and dramatically higher power output from the same copper, magnet, and iron mass..

Super true. I've been stalking companies all over europe begging for efficient 2Kw 3500rpm motors suitable for small EVs. Not success so far. It seems everyone is 100% busy trying to capture either the servo market (high speed super heavy spinner with large reduction) or the large EV buisness, like cars. I think it will only change if the legislation relaxes, and higher power motors become legal. I'm for sure no fan of 40mph bicycles, but 1000 to 2000Kw is just mandatory if you want to carry some meaningful weight outside the super flat northern european plain.
 
Yeah, ebikes with some power are in a very strange spot.

The scooter world is doing us no justice and there is little interest in having exceptional mileage or range in that world apparently.
We do have much better controllers these days, so the spendy RC motors are much more usable. That wasn't the case 5 years ago.
 
neptronix said:
There are a bunch of small, lightweight, high power mid drives on the market.

Well please, share the knowledge because I would like to know. Cyclone, GNG have trash power density and are big, da vinci uses an astro with an impractical reduction and tangent already mentioned. Lightning rods are frickin gigantic.
 
qwerkus said:
Interesting feedback. Do you happen to have some pictures ? 7500RPM is alot though :shock: I'd need to halve it at least to get something useful. That's why I was talking WYE/Delta hack or rewind; not to get more power per weight, but better efficiency at 14s and a medium reduction. Currently looking for the biggest motor I could squeeze into my frame, and this one, together with a 1:10 reduction could be a suitable candidate. But a 24V system with super big wires / controller for high amps just won't do it. Also, I'd have to trim the 124mm version to 100-110 max - hence the wish to see what's inside.

Ask and you shall receive!
 

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coleasterling said:
Ask and you shall receive!


Ubercool, thanks a lot. Copper fill seems not bad at all. On the other hand, it looks like a pretty tight fit. No chance to trim the 124mm version of this motor to around 100mm. Well, that settles it. The rotor seems rather long but tiny. Smaller dia. than the bbshd. Only 6 poles. That explains the rather anemic torque value. I d need fast spin and super high reduction (like 1:20) to tow useful weigts with this. Not doable with a single stage reduction.
 
qwerkus said:
Ubercool, thanks a lot. Copper fill seems not bad at all. On the other hand, it looks like a pretty tight fit. No chance to trim the 124mm version of this motor to around 100mm. Well, that settles it. The rotor seems rather long but tiny. Smaller dia. than the bbshd. Only 6 poles. That explains the rather anemic torque value. I d need fast spin and super high reduction (like 1:20) to tow useful weigts with this. Not doable with a single stage reduction.

The KV is somewhere around 95. The bike we're running it on has an 11 tooth 25h front and 80 tooth rear sprocket, with 14" rolling diameter wheels, so a lot smaller than a bicycle. It does very, very well loaded. I like the stator enough that I've considered building another rotor for it.
 
That's a lot nicer constructed motor than i expected for the price. I've actually ordered a couple motors designed like this and they were turds every time. Please forgive my skepticism.

If it has 0.35mm lams, it is worth spinning up..
Although with how the magnets are retained, there are limits to how fast you want to spin it.. lest the magnets go flying.

Mounting is also an issue due to it's shape and the weight disbalance the longer one will induce.
tall motors ftw..
 
coleasterling said:
qwerkus said:
Ubercool, thanks a lot. Copper fill seems not bad at all. On the other hand, it looks like a pretty tight fit. No chance to trim the 124mm version of this motor to around 100mm. Well, that settles it. The rotor seems rather long but tiny. Smaller dia. than the bbshd. Only 6 poles. That explains the rather anemic torque value. I d need fast spin and super high reduction (like 1:20) to tow useful weigts with this. Not doable with a single stage reduction.

The KV is somewhere around 95. The bike we're running it on has an 11 tooth 25h front and 80 tooth rear sprocket, with 14" rolling diameter wheels, so a lot smaller than a bicycle. It does very, very well loaded. I like the stator enough that I've considered building another rotor for it.

Hmm. How much would you say could be shaven off this motor to make it shorter ? There is only so much space left between bike cranks. Also how would you go about machining another rotor? Seems a lot of trouble for little gain.
 
qwerkus said:
Hmm. How much would you say could be shaven off this motor to make it shorter ? There is only so much space left between bike cranks. Also how would you go about machining another rotor? Seems a lot of trouble for little gain.

I'll have to disassemble and measure, but will get back to you on that.

I'm not sure there's only little gain to be made. Think what the power would look like if we could reasonably increase the RPM to 12k. The magnets in it now are also very thin and there's plenty of room for larger ones, which would drop the KV and let us up the voltage significantly.

I own a full CNC machine shop with a couple VMC's (one 4 axis, one 3), a 2 axis lathe, and a 3 axis lathe with live tooling. We're pretty capable of machining a new rotor :)
 
SpringHalo said:
Ben Katz measured a motor with the same form factor on his dyno and as you'd guess, efficiency is pretty marginal.

Thanks for the link.
Low 80% is pretty sad and what i expected.

I do wonder if the test was out of the optimal RPM range, or if the motor really is that bad.
 
neptronix said:
flat tire said:
This is 2019, why do we still not have small, lightweight, high power mid drives readily available?
There are a bunch of small, lightweight, high power mid drives on the market.

Still waiting, bud, you've come back to this thread a couple times but didn't respond to what should be an "easy" question so I'll pose it again:

what are those good mid drives you say are readily available, excluding the bulky crappy ones listed above?
 
flat tire said:
what are those good mid drives you say are readily available, excluding the bulky crappy ones listed above?

cyclone mini, gng/cyc x1 pro, tangent, davinci drive, etc.. the power density is there..

The lack of noise and good reliability? maybe the davinci drive is it.
if you want cheap, the gng/cyc x1 pro seems good. seems to not be too loud when driven with a foc, as demonstrated by alan chinito hu.
 
neptronix said:
The lack of noise and good reliability? maybe the davinci drive is it.
if you want cheap, the gng/cyc x1 pro seems good. seems to not be too loud when driven with a foc, as demonstrated by alan chinito hu.

Thanks for taking the time to read the thread and reply:

flat tire said:
Cyclone, GNG have trash power density and are big, da vinci uses an astro with an impractical reduction and tangent already mentioned. Lightning rods are frickin gigantic.

I guess you didn't read the thread. There are 2 non-shitty compact high power mid drives on the market (tangent, da vinci) and both have massive drawbacks. I don't care about cost. I prefer 6KW+, ideally 10KW+.
 
i did read your post. Those are the highest power density drives around.. i don't see what the problem with the davinci is.. the gng/cyc x1 pro is still an unknown. I just disagree with you, that they're both no good.

I've found videos of astros being ran with ASI/phaserunner style controllers.. so we can say that the controller problem is solved.

You'll have a hard time finding any motors that are power dense than an astro. If/when you do, you'll also find that an unobtanium controller is needed to run them ( ultra low inductance/too high eRPM ), or they've exaggerated their specs and quoted a peak power as a continuous power ( alien power systems, hobbyking, etc are all guilty of this )

You're looking at something more along the lines of an emrax, especially with the 10kw requirement. More suitable for a motorcycle, for sure.
 
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I own both these motors... (1000W & 1200W MY1020)
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neptronix said:
I've found videos of astros being ran with ASI/phaserunner style controllers.. so we can say that the controller problem is solved.

Well that's been possible since day 1...you just have to put up with sensorless, and ASI's dead-stop startup algorithm kind of sucks. Unless you add halls.

I'm not asking for better MOTORS than astroflight. Their motors are perfect but unfortunately a mid drive is a full system. Tangent's would be perfect except it's loud. Da Vinci has too many big uncovered moving parts, and only works with certain bike frames.
 
flat tire said:
Well that's been possible since day 1...you just have to put up with sensorless, and ASI's dead-stop startup algorithm kind of sucks. Unless you add halls.

I'm not asking for better MOTORS than astroflight. Their motors are perfect but unfortunately a mid drive is a full system. Tangent's would be perfect except it's loud. Da Vinci has too many big uncovered moving parts, and only works with certain bike frames.

One could create a cover for a davinci drive or go along the lines of this idea to create your own dual reduction:
https://www.endless-sphere.com/forums/viewtopic.php?f=28&t=22245&start=0
Hell, i've seen some reductions made with cnced plates ( from online services such as big blue saw ) that were bolted together, so you could in theory make a nice looking astro drive and perhaps sell it..

How bad is the sensorless start on an ASI?
 
The sensorless start on ASI is terrible, somewhere just a tick above unusable and tuning parameters are very limited. If high torque is needed you can pretty much forget about being able to start with throttle alone. For comparison Castle HV160 and Powervelocity sensorless are both way superior. Which is odd because ASI does everything else better.
 
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