Does the KS16B has less torque than the Ninebot E+?

[Roland]

So I am a beginner and avid reader of this forum. And for various reasons I have started more or less with a ninebot E+ and now I just received a Kingsong 16B. ... When I tried to scale from a standstill a step of less than an inch high the Ninebot was able to do it right away. ... Now using the Kingsong 16B (in player mode) felt like trying to scale a wall. The 16B leaned in and nothing happend without taking this small step with some speed. The Ninebot also seems to be much smoother on crawling speeds (less than 1 kph). Could it be that there are more magnets in the Ninebot? 

 

Roland

 

[HermanTheGerman]

On 21.7.2017 at 10:34 PM, Roland said:

When I tried to scale from a standstill a step of less than an inch high the Ninebot was able to do it right away. ... Now using the Kingsong 16B (in player mode) felt like trying to scale a wall. The 16B leaned in and nothing happend without taking this small step with some speed.

Try it in riding mode. The KS16 has a lot more torque than the old Ninebot wheels.

On 21.7.2017 at 10:34 PM, Roland said:

 The Ninebot also seems to be much smoother on crawling speeds (less than 1 kph). Could it be that there are more magnets in the Ninebot?

I assume it will be hard to get an answer for these questions, because not many KS16 riders ever try to "crawl" with a wheel which is able to do 30 km/h, at least I never do. At pedestrian speeds or a little bit slower I never recognized any anomalies. I also never try to start against a curbstone, though I'm crossing them with moderate speed (again around pedestrian speed) without problems, I would say up to a height of approximately 10 cm.

[Chriull]

On 21.7.2017 at 10:34 PM, Roland said:

So I am a beginner and avid reader of this forum. And for various reasons I have started more or less with a ninebot E+ and now I just received a Kingsong 16B. ... When I tried to scale from a standstill a step of less than an inch high the Ninebot was able to do it right away. ... Now using the Kingsong 16B (in player mode) felt like trying to scale a wall. The 16B leaned in and nothing happend without taking this small step with some speed.

Which firmware version do you have? Starting from standstill against a burden could destroy your wheel!

The KS has a more powerfull motor than the ninebot - try it with a little bit of speed and you'll notice the difference.

KS (and also GW imho) had some probs with "starting the wheel up" - they have some current/power limiter implemented, so the wheel cannot overpower/fry the mosfets but this caused  sometimes with some firmeware versions that they wheel did not "start well from standstill"

On 21.7.2017 at 10:34 PM, Roland said:

The Ninebot also seems to be much smoother on crawling speeds (less than 1 kph).

Yes - have the same memory from my ninebot. Seems he has some better firmware algorithm for controlling the motor at low speeds.

On 21.7.2017 at 10:34 PM, Roland said:

Could it be that there are more magnets in the Ninebot? 

Have no idea - but that should not be the reason...

 

 

 

[Roland]

Firmware is 1.25. and its the 800 watt version... but ... yeah I think I will not do that again ...

And looking at the Gotway battery connection problem (bad diameters for the spottwelded connectors on the cells lead to heatspots of 200+ °C  and molten/burned holes in the battery package - if currents high enough run through) ... sigh ...

That something like such seemingly innocent testing of the abilities could harm your wheel ...
But its interesting ...

It really is a field that is still very much in development ... 

Thank you for the input and the warning ... did not make the connection!

[Justina]

Keep practising. The ride experience differs from Ninebot. It is true there could be an impression of a slight delay before the KS16 starts accelerating, but if you lean a bit more, it will actually launch like a rocket. Of course, I'm not encouraging you to go crazy  

Quite the opposite - you need to change your old habits.

For instance, KS16 is much better balanced than 9B1, because it has batteries on both sides (in contrast, Ninebot has battery on one side only). It is very common to have issues with balance after switching from Ninebot, as one of your legs is subconsciously trying to compensate the memorized weight difference.

Also, play a bit with the settings and you'll see after a week you'll be able to keep even better balance at lower speeds than on Ninebot, and you'll be happy nothing is beeping when you exceed 23 km/h ;-) The 30 km/h speed limit is perfect - it makes a huge difference, because most of the time in the city you won't even reach the max. speed, while you will be exceeding 23 km/h very often.

Have fun!

[dpong]

Based on this thread I tried going super slow on my new KS16S, and it works great.  I spent a lot of time doing this on my Ninebot One E+ also, sort of a specialty of mine, meh, call it a hobby.  I found that the KS16S balances just great going super slow.  Not sure I'd say it is better than NB1, but it is just as good.  No problem at all.  I love that super slow feeling.  

[Roland]

14 minutes ago, dpong said:

Based on this thread I tried going super slow on my new KS16S, and it works great.  I spent a lot of time doing this on my Ninebot One E+ also, sort of a specialty of mine, meh, call it a hobby.  I found that the KS16S balances just great going super slow.  Not sure I'd say it is better than NB1, but it is just as good.  No problem at all.  I love that super slow feeling.  

Well as I said in the beginning: I tried it from a stand still. Actually  just a door threshold/doorstep, but still about a little less than an inch. The Ninebot was firm - did not lean in and just took me over it (83kg + weight of the ninebot). The KS16B (NOT!  KS16S) leaned in and was not able to climb it. But mind you I only have 800W and also the smalles battery (320Wh). The KS16S is a totally different beast for sure!
(P.S. Mode was the firmest... Player mode)

[steve454]

23 minutes ago, Roland said:

The KS16B (NOT!  KS16S) leaned in and was not able to climb it. But mind you I only have 800W and also the smalles battery (320Wh). The KS16S is a totally different beast for sure!
(P.S. Mode was the firmest... Player mode)

Wow, I didn't know Kingsong sold anything with that small of a battery.  That led me to another thread about the differences between the KS16A and KS16B.  So the A was the prototype of the new shell design, and the B was the actual production model, which is what you have.  So you have about the same battery size as the Ninebot.  How do they compare while riding at about 8 to 16 kmh?  Does the motor have more noise in the Kingsong?

[steve454]

43 minutes ago, dpong said:

Based on this thread I tried going super slow on my new KS16S, and it works great.  I spent a lot of time doing this on my Ninebot One E+ also, sort of a specialty of mine, meh, call it a hobby.  I found that the KS16S balances just great going super slow.  Not sure I'd say it is better than NB1, but it is just as good.  No problem at all.  I love that super slow feeling.  

I just started trying to go very slow, it's fun.  It seems that I am getting more of a feel for the balance that riding faster doesn't give.  I started doing it to learn backwards riding, and found that I can now do short pendulums of about 10 feet backward to forward up to 5 or 6 times before I have to step off.  I still can't ride backward more than about 10-15 feet at one time, but the pendulum training is progressing faster than just pure going backwards training, and it's more enjoyable.  I feel more in touch with the wheel.

[Roland]

9 minutes ago, steve454 said:

Wow, I didn't know Kingsong sold anything with that small of a battery.  That led me to another thread about the differences between the KS16A and KS16B.  So the A was the prototype of the new shell design, and the B was the actual production model, which is what you have.  So you have about the same battery size as the Ninebot.  How do they compare while riding at about 8 to 16 kmh?  Does the motor have more noise in the Kingsong?

being a beginner and so ... let me lead you to different thread... and yes there is a certain amount of noise:

 

[HermanTheGerman]

18 hours ago, Roland said:

Well as I said in the beginning: I tried it from a stand still. Actually  just a door threshold/doorstep, but still about a little less than an inch. The Ninebot was firm - did not lean in and just took me over it (83kg + weight of the ninebot). The KS16B (NOT!  KS16S) leaned in and was not able to climb it. But mind you I only have 800W and also the smalles battery (320Wh).

Be careful with that wheel, when you are riding faster, especially when the battery is low !

It has a lot less spare power when you cross a small hole or a bump.

When you are more experienced and want to ride faster (which will happen soon ), I recommend to buy a spare pack and apply it on the other side of the wheel, so that you have the 640Wh. The wheel is also a lot better balanced then, because now you have the heavy accupack only on one side.

And you are right, the wheel is louder than the Ninebot, but I see that as an advantage: Most of the time when I approach people, they already hear me when I'm 10 meters away, which is better as when I must greet them from behind, which sometimes leads to surprising reactions.

[Keith]

On 21/07/2017 at 9:34 PM, Roland said:

Could it be that there are more magnets in the Ninebot? 

It's extremely likely that it is the number of winding turns rather than the number, strength, size, etc of magnets. There will always be as many magnet pairs as it is physically possible to fit in the available space.

what is being forgotten here is Kv which equates to RPM/Volt. This is controlled by the number of turns, magnet strength number of poles, etc, etc. To have a higher maximum speed you need a higher Kv or you will run out of torque and faceplant. Maximum torque is inversely proportional to Kv. So a lower powered but low Kv wheel can have more torque available at Zero RPM than a higher powered but also higher Kv wheel. Conversely at high speed the high Kv wheel will have more torque still available than the low Kv wheel where the torque will be getting very close to zero. Really kV is comparable to a gear ratio a low kV wheel is like it's in first gear all the time, a high kV wheel is like it is in forth gear. Which one do you think is going to climb a steep incline better?

Higher Kv wheels also have lower winding resistance as they will have less turns of much thicker wire, this means they are capable of sinking a lot more current.

RPM and therefore back e.m.f. is what puts a limit on that current so worst case is leaning hard forward with zero RPM. i.e. I absolutely wouldn't recommend trying to climb up a kerb from a standing start on any high speed wheel.

[Christoph Zens]

On 25.7.2017 at 10:41 AM, Chriull said:

Yes - have the same memory from my ninebot. Seems he has some better firmware algorithm for controlling the motor at low speeds.

What I noticed is that on the ninebot, there is no dead-band. Standing on the pedals (holding on to a wall), I can do very small weight shifts (forward/backward) and the wheel immediately responds with motor movement. On my KS16S, there is a dead-band where I can tilt the pedals back and forth a little without any reaction from the motor. In this small zone, it feels like the wheel is off and not balancing at all. When going super slow, this dead-band may add a subtle weird feeling, as the "input" on the pedals is extremely small, and the rider could notice that the wheel doesn't respond to that tiny change in balance he was just executing. I usually do not notice the dead-band during normal riding, but the stand-still test is very reproducible. Anyone else can confirm this, or is it only my wheel?

[Justina]

It may be related to the fact that KingSong (and Gotway for instance) use 3-pole control in their motors, while Ninebot (Inmotion and IPS as well) use 6-pole control. The 3-pole configuration is easier to build, but the precision of the wheel rotation at low speeds is more difficult to achieve. It can be improved by proper electronics and software, but 6-pole motors are overall more fluent at low speeds. If you want to read some more technical details, check this out.

However, I've ridden the flagships of all the mentioned brands and I'm positive you can ride each one at low speeds. It's not always so easy, some wheels do it better, but with some practice you can harness any wheel  For example, you can try some more energetic moves when changing the riding direction of your 16S.

Bare in mind that some huge KS-16S firmware updates are in advanced phases of development. You can expect some big changes, some more features and settings in the app, and most importantly... improved motor control algorithms. It's possible they already improved the low-speed precision of the KS-16S. Stay tuned 

Besides, the KS-16S is a completely new wheel in the same shell (just silver :-) ). The motherboard was redesigned, the motor is also brand new, thus the motor control algorithms are different. These factors may resulting in different riding experience than on other KingSong unicycles.  

[esaj]

On 8/1/2017 at 5:48 PM, Christoph Zens said:

What I noticed is that on the ninebot, there is no dead-band. Standing on the pedals (holding on to a wall), I can do very small weight shifts (forward/backward) and the wheel immediately responds with motor movement. On my KS16S, there is a dead-band where I can tilt the pedals back and forth a little without any reaction from the motor. In this small zone, it feels like the wheel is off and not balancing at all. When going super slow, this dead-band may add a subtle weird feeling, as the "input" on the pedals is extremely small, and the rider could notice that the wheel doesn't respond to that tiny change in balance he was just executing. I usually do not notice the dead-band during normal riding, but the stand-still test is very reproducible. Anyone else can confirm this, or is it only my wheel?

I think I've noticed this, but can't say for sure. Have to pay more attention to this the next time I ride.

7 hours ago, Justina said:

Bare in mind that some huge KS-16S firmware updates are in advanced phases of development. You can expect some big changes, some more features and settings in the app, and most importantly... improved motor control algorithms. It's possible they already improved the low-speed precision of the KS-16S. Stay tuned 

Nice, but considering that at least both Ninebot (bricking wheels) and Gotway (oscillation bug) have f***ed up big time in the past with their firmware updates, I'm not going update until much later, when other crash test dummies have given all-clear on the new firmware.

[Keith]

9 hours ago, Justina said:

The 3-pole configuration is easier to build, but the precision of the wheel rotation at low speeds is more difficult to achieve. It can be improved by proper electronics and software, but 6-pole motors are overall more fluent at low speeds. If you want to read some more technical details, check this out.

When is saw that @esaj had replied, I thought it was to comment on that linked article as to me (and I freely admit it might just be me) the entire article seems very dubious. 

For a start, what on earth does 6-pole configuration mean? Poles are the magnet North and South bits, when you talk about a motor being 6-pole you mean the number of magnetic poles in the motor, EUC's have loads, never as few as 6 - let alone 3 and BLDC are usually driven three phase I.e. There are usually 3 connections leaving the motor to the controller so it cannot connect every 6th pole, it will surely, be every third? If it does connect every 6th pole it is a 6 phase motor - not a 6-pole configuration motor. That would mean there are 12 power switches. These do give better torque at very low speed but much worst switching losses at higher speed, very good reasons for KingSong and Gotway NOT to use them.

More worrying are the other errors in the article which makes the whole thing questionable.

• Why show a diagram of an in-runner motor whilst discussing out-runner motors, "magnets connected to the outer rim" and show a picture of coils on the outer rim.
• Quote: "Normal brushed motors can operate with voltage directly from the AC power found in your wall sockets in every home." the majority of brushed motors are d.c. Using brushes on an a.c. Motor is only done with additional control circuitry - not direct from the a.c., with the exception of some motors with electromagnets in both stator and rotor, (so called "universal motors which will run on a.c. or d.c.) and they are hardly "normal!
• Quote: "permanently fixed magnets (ferro-magnets)" ferro-magnets is the term used for purely iron magnets, not those that include rare earth minerals, no EUC uses ferro-magnets.
• Quote: "and most importantly, the user is free to control the rotational speed almost independently of the motor torque." Errrrr. Torque = power/RPM, so that statement is rubbish isn't it, torque is related to RPM by the amount of power you apply - on any motor.

I am always willing to learn but it has been a long while since I've read an article I have trusted less than this one - sorry.

[Mono]

1 hour ago, Keith said:

Quote: "and most importantly, the user is free to control the rotational speed almost independently of the motor torque." Errrrr. Torque = power/RPM, so that statement is rubbish isn't it, torque is related to RPM by the amount of power you apply - on any motor.

Not sure you are entirely right on this one. Bare with me: you can go at a given speed, say 15km/h, straight, or on an incline, or slightly downhill. The three cases will lead to the application of between almost zero torque (downhill) to maximal torque (incline) at the very same speed. The point is of course that the motor doesn't need to apply its maximal torque/power at any given speed. This being true for "any" speed means that the choice of speed and torque is to a large extend independent (of course there are limits, as the maximal torque depends decisively on speed). I agree that the wording in the article is chosen rather strangely though. And the link is certainly also a disguised ad. 

[Keith]

1 hour ago, Mono said:

Not sure you are entirely right on this one. Bare with me: you can go at a given speed, say 15km/h, straight, or on an incline, or slightly downhill.

Ah, @Mono, you've picked up the wrong emphasis on what I quoted. First of all downhill, uphill, on the straight at the same speed will all use different amounts of power so in each case the torque applied will be proportional to the power applied (as in these examples RPM is a constant If speed doesn't change). I.e. you don't control the speed independently of the torque, it is the power, and hence torque you apply that controls the speed - in any given terrain/condition. You really cannot say torque power and speed are independent of each other. I.e. Given static outside conditions, a hill of constant incline for example, if you wish to go slower or faster (I.e. "Control the rotational speed") then you have to change the power and therefore torque - they are not independent, only varied by outside conditions (change in hill gradient etc.) 

However, the key thing was that the article said: "most importantly <for a brushless motor>The user is free to control the rotational speed etc.etc.etc." surely, as in the examples you gave above you can do that for any electric motor, it is a nonsense to infer it is special to BLDC motors - that was the point I was making.

[Mono]

It depends of what we define as control parameter. Using the environment as control parameter (it is a parameter we can indeed actually control, i.e. we have control over where we ride), we can get within the physical limits any torque independently of speed or any speed independently of torque. That's all, and in a very broad sense it justifies to say "the user is free to control the rotational speed almost independently of the motor torque".

EDIT: Reading the paragraph in the article in the most charitable way, I would say that this is what the author meant: the motor has the feature to adapt to any environmental condition by a free "choice" of speed and torque.

1 hour ago, Keith said:

However, the key thing was that the article said: "most importantly <for a brushless motor>The user is free to control the rotational speed etc.etc.etc."

Sorry, that was not reflected in your previous quote and I didn't go through the article, I just commented on the quote you gave, so I missed the context. 

[Justina]

13 hours ago, esaj said:

I think I've noticed this, but can't say for sure. Have to pay more attention to this the next time I ride.

Nice, but considering that at least both Ninebot (bricking wheels) and Gotway (oscillation bug) have f***ed up big time in the past with their firmware updates, I'm not going update until much later, when other crash test dummies have given all-clear on the new firmware.

Smart approach  I think guys from KingSong are aware of what the other companies have done wrong with updates, that is why they do not release anything until it's fully tested internally, which takes a while. Of course, no matter how good the beta tests are, there is still a risk of not detecting all bugs, so it's always good to wait a bit before upgrading.

 

12 hours ago, Keith said:

When is saw that @esaj had replied, I thought it was to comment on that linked article as to me (and I freely admit it might just be me) the entire article seems very dubious. 

For a start, what on earth does 6-pole configuration mean? Poles are the magnet North and South bits, when you talk about a motor being 6-pole you mean the number of magnetic poles in the motor, EUC's have loads, never as few as 6 - let alone 3 and BLDC are usually driven three phase I.e. There are usually 3 connections leaving the motor to the controller so it cannot connect every 6th pole, it will surely, be every third? If it does connect every 6th pole it is a 6 phase motor - not a 6-pole configuration motor. That would mean there are 12 power switches. These do give better torque at very low speed but much worst switching losses at higher speed, very good reasons for KingSong and Gotway NOT to use them.

More worrying are the other errors in the article which makes the whole thing questionable.

• Why show a diagram of an in-runner motor whilst discussing out-runner motors, "magnets connected to the outer rim" and show a picture of coils on the outer rim.
• Quote: "Normal brushed motors can operate with voltage directly from the AC power found in your wall sockets in every home." the majority of brushed motors are d.c. Using brushes on an a.c. Motor is only done with additional control circuitry - not direct from the a.c., with the exception of some motors with electromagnets in both stator and rotor, (so called "universal motors which will run on a.c. or d.c.) and they are hardly "normal!
• Quote: "permanently fixed magnets (ferro-magnets)" ferro-magnets is the term used for purely iron magnets, not those that include rare earth minerals, no EUC uses ferro-magnets.
• Quote: "and most importantly, the user is free to control the rotational speed almost independently of the motor torque." Errrrr. Torque = power/RPM, so that statement is rubbish isn't it, torque is related to RPM by the amount of power you apply - on any motor.

I am always willing to learn but it has been a long while since I've read an article I have trusted less than this one - sorry.

 

10 hours ago, Mono said:

Not sure you are entirely right on this one. Bare with me: you can go at a given speed, say 15km/h, straight, or on an incline, or slightly downhill. The three cases will lead to the application of between almost zero torque (downhill) to maximal torque (incline) at the very same speed. The point is of course that the motor doesn't need to apply its maximal torque/power at any given speed. This being true for "any" speed means that the choice of speed and torque is to a large extend independent (of course there are limits, as the maximal torque depends decisively on speed). I agree that the wording in the article is chosen rather strangely though.

 

9 hours ago, Mono said:

It depends of what we define as control parameter. Using the environment as control parameter (it is a parameter we can indeed actually control, i.e. we have control over where we ride), we can get within the physical limits any torque independently of speed or any speed independently of torque. That's all, and in a very broad sense it justifies to say "the user is free to control the rotational speed almost independently of the motor torque".

EDIT: Reading the paragraph in the article in the most charitable way, I would say that this is what the author meant: the motor has the feature to adapt to any environmental condition by a free "choice" of speed and torque.

Sorry, that was not reflected in your previous quote and I didn't go through the article, I just commented on the quote you gave, so I missed the context. 

Thank you, guys, for the discussion. Let's get one thing straight - I'm not the author of the article, it has been written by an electronic engineer, as stated in the preamble. Is it a disguised ad? Sure it is, because there are tons of articles about electric unicycle motors  @Mono, I actually had a feeling you will reply here. I've read some of your posts and they are very technical focused. It's a pitty all of these discussions are just on a forum. Have you ever thought about creating a blog or a website with technical stuff gathered together? I'm serious. Maybe one day I could link some yours. There is a lot of potential in your and some other users' posts. It's too bad it's hard to find and no one really reads the whole forum.

The web is still lacking proper content regarding electric unicycles, that's why we're trying to create high quality content. So did you guys come to a conclusion in regard to the article, or still aren't sure? In physics there should only be one truth, there's no place for "maybe". If you are 100% sure the quoted sentences are false, I will forward your feedback. Proper corrections will be applied. If the errors are not related to incorrect translation (the original text is not in English, and the translator doesn't have any engineering knowledge), the author is so fired 

 

Getting back ON topic:

My understanding is that despite the rated power, there are major differences in the motor built among different EUC manufacturers. It is possible that KS-16S has more power than Ninebot One E+ (well, it's actually a fact - KS-16S is indeed more powerful), but due to the motor construction, Ninebot may be more fluent on lower speeds (for now). However, a lot can be done with a proper algorithm. But take an E+ and 16S to go step uphill from zero speed. Ninebot won't make it or will make it really slow (the wheel is great, but it slows down when going uphill even with some initial speed), while 16S will be doing the job and still accelerating. 

Like I said, KS-16S has a completely new motor and there are already some changes in the new firmware regarding the motor control. Besides that, you can also expect more adjustable riding modes and overall behaviour/responsiveness.

As far as I remember Ninebot has released a major motor control change too, starting from v.1.3.5 or so. The difference is noticeable, and not everyone likes the new algorithm. I have still an E+ with 1.3.0. Fortunately I have never had issues with upgrading the E+, but I've read on the forum it was harsh for some riders 

 

By the way, comparing different wheels side by side and expecting them to behave the same is not realistic. Different wheel, different impressions.

I know most riders switching from Ninebot One E+ for instance, expect the new wheel to be the same, just faster. The truth is it won't be the same. You always need to get use to it, change your habits, do some test rides before using it in the city. People don't like changes, but you have to expect different experience when changing the EUC, especially when switching to another brand.

[Mono]

6 hours ago, Justina said:

The web is still lacking proper content regarding electric unicycles, that's why we're trying to create high quality content. So did you guys come to a conclusion in regard to the article, or still aren't sure? In physics there should only be one truth, there's no place for "maybe". If you are 100% sure the quoted sentences are false, I will forward your feedback. Proper corrections will be applied. If the errors are not related to incorrect translation (the original text is not in English, and the translator doesn't have any engineering knowledge), the author is so fired 

OK, I now I have read the article. While I have a higher education in mathematics and engineering, I don't really know myself any of the details of electric motors. I only can judge by my educated common sense. From there, I may figure a few possible inaccuracies or oversimplifications, but I don't see anything obviously wrong. I know that technical writing is always a delicate balance between intelligible briefness and comprehensive accuracy.

[Mono]

20 hours ago, Keith said:

ferro-magnets is the term used for purely iron magnets

The word ferromagnetic (as opposed to paramagnetic, diamagnetic, and antiferromagnetic) is apparently also used for the type of magnetism, independently of the material.

"Only a few substances are ferromagnetic; the most common ones are iron, nickel and cobalt and their alloys. The prefix ferro- refers to iron, because permanent magnetism was first observed in lodestone, a form of natural iron ore called magnetite, Fe₃O₄.". 

https://en.wikipedia.org/wiki/Magnetism

[esaj]

22 hours ago, Keith said:

For a start, what on earth does 6-pole configuration mean? Poles are the magnet North and South bits, when you talk about a motor being 6-pole you mean the number of magnetic poles in the motor, EUC's have loads, never as few as 6 - let alone 3 and BLDC are usually driven three phase I.e. There are usually 3 connections leaving the motor to the controller so it cannot connect every 6th pole, it will surely, be every third? If it does connect every 6th pole it is a 6 phase motor - not a 6-pole configuration motor. That would mean there are 12 power switches. These do give better torque at very low speed but much worst switching losses at higher speed, very good reasons for KingSong and Gotway NOT to use them.

The talk about 3- and 6-pole motors sounded a bit weird, considering that what I've understood to be the poles in a motor are the coils and the magnets, often you see motor classifications with "pole"-counts for rotors and stators separately:

Somewhere I also saw a calculator for motor winding where you gave the number of "poles" (coils) and magnets, the pole (stator coil) count should always be divisible by 3 though (for 3-phase motors). Either way would make most EUC motors more like 57-60 poles/coils and a few more magnets? Personally I've become convinced that (at least most) EUC-motors are actually PMSMs, not "plain" BLDCs, although the difference is "just" in the windings (sinusoidal vs. trapezoidal back-EMF, just hook your unpowered motor to an oscilloscope and turn the motor by hand), and I've seen the names sometimes being used interchangeably. PMSM would appear better suited for sinewave-drive/field-oriented control (FOC) -algorithms due to the back-EMF waveform and should give smoother acceleration and running, and probably more accurate control, which is needed in balancing? I've been meaning to dive deeper into FOC for a long time, and have read many application notes about the implementation, but so far haven't gotten around to build my own controller to see if I can drive the Firewheel motor 

Firewheel motor back-EMF:

 

But I'm still not that certain on the terminology, and if the person writing the article is an electrical/electronics engineer, I'd expect him/her to know better than me    It could be that the article was simplified, because most people arent' that interested in all the technical details and/or something was lost in translation. 

[steve454]

On 8/1/2017 at 9:48 AM, Christoph Zens said:

What I noticed is that on the ninebot, there is no dead-band. Standing on the pedals (holding on to a wall), I can do very small weight shifts (forward/backward) and the wheel immediately responds with motor movement. On my KS16S, there is a dead-band where I can tilt the pedals back and forth a little without any reaction from the motor. In this small zone, it feels like the wheel is off and not balancing at all. When going super slow, this dead-band may add a subtle weird feeling, as the "input" on the pedals is extremely small, and the rider could notice that the wheel doesn't respond to that tiny change in balance he was just executing. I usually do not notice the dead-band during normal riding, but the stand-still test is very reproducible. Anyone else can confirm this, or is it only my wheel?

I have noticed a dead-band on the ninebot E+ when the riding sensitivity is set to 6 or higher, not while riding but when slowing down and reversing or just standing on the wheel holding on to something and rocking back and forth.   When set at hard pedals riding mode, I don't feel a dead-band.  Is your KS16S set at the hardest setting?  Does the dead-band get larger at the softer setting?  I always thought it felt weird on the ninebot to have that, I just thought it was poor algorithm or something.  I am on the latest firmware 1.4.0

[Christoph Zens]

1 hour ago, steve454 said:

I have noticed a dead-band on the ninebot E+ when the riding sensitivity is set to 6 or higher, not while riding but when slowing down and reversing or just standing on the wheel holding on to something and rocking back and forth.   When set at hard pedals riding mode, I don't feel a dead-band.  Is your KS16S set at the hardest setting?  Does the dead-band get larger at the softer setting?  I always thought it felt weird on the ninebot to have that, I just thought it was poor algorithm or something.  I am on the latest firmware 1.4.0

Good point. I was comparing the NB1 fw 1.4.0 at setting 3 to the KS16S at riding mode (medium setting). That seems to be an invalid comparison. I will try again with the KS16S set to player mode (hardest setting). Maybe the dead-band goes away. I always assumed that such a dead-band must be an unwanted motor controller flaw, as softer riding modes should only decrease the sensitivity to balance errors. But as the sensitivity decreases, very small errors may turn out to result in no motor movement.