Solo motor and pod info sought...

[J R]

Hey Folks,

I purchased 4 new Solo motors with pods attached. I was somewhat concerned about one of my old motors and decided to buy 4 so I could start a small inventory of Solo parts. (It can take quite a while to get parts from China.) The questionable motor had a different pitch than the other 3, was quite a bit different in the vibration test graph using the vibrate app with MP and when slowly turning it by hand was quite smooth. The other 3 had a more pronounced "cog" or "tick" feel to them.

I received the new motors a couple of days ago. Upon inspection the new motors seemed to have an even more pronounced "cog/tick". Because of this I assumed the more pronounced "cog/tick" was due to the fact that they were brand new. I had also read that they may have made the newer motors a bit better than the first iteration. I decided that I'd go ahead and replace all 4 and keep my used ones for backup.

I went about installing the new pods (quite easily, I might add!). When I got to the last new pod I noticed it had that smooth feel to it as well. The other 3 had a very distinct "cog/tick" to them. I really wanted these motors to be consistent across all four, so at this point I took one of my old motors with the more distinct "cog/tick" and used it to replace the last motor. (and yes, I was careful to insure it was the proper direction!)

I guess the question/information I'm looking for is how should these motors feel? smooth or with the more distinct "cog/tick"? Would you do as I did or would you replace the last one with the new smooth one anyway? Sorry for the lack of correct terminology, as you can tell my experience with electric motors is subpar. My other multi rotors seem to have a pretty smooth "cog/tick" feel to them but it is there, just not nearly as distinct.

Any help would be much appreciated. Thanks,

Jerry

 

[Maddog]

Hey Folks,

I purchased 4 new Solo motors with pods attached. I was somewhat concerned about one of my old motors and decided to buy 4 so I could start a small inventory of Solo parts. (It can take quite a while to get parts from China.) The questionable motor had a different pitch than the other 3, was quite a bit different in the vibration test graph using the vibrate app with MP and when slowly turning it by hand was quite smooth. The other 3 had a more pronounced "cog" or "tick" feel to them.

I received the new motors a couple of days ago. Upon inspection the new motors seemed to have an even more pronounced "cog/tick". Because of this I assumed the more pronounced "cog/tick" was due to the fact that they were brand new. I had also read that they may have made the newer motors a bit better than the first iteration. I decided that I'd go ahead and replace all 4 and keep my used ones for backup.

I went about installing the new pods (quite easily, I might add!). When I got to the last new pod I noticed it had that smooth feel to it as well. The other 3 had a very distinct "cog/tick" to them. I really wanted these motors to be consistent across all four, so at this point I took one of my old motors with the more distinct "cog/tick" and used it to replace the last motor. (and yes, I was careful to insure it was the proper direction!)

I guess the question/information I'm looking for is how should these motors feel? smooth or with the more distinct "cog/tick"? Would you do as I did or would you replace the last one with the new smooth one anyway? Sorry for the lack of correct terminology, as you can tell my experience with electric motors is subpar. My other multi rotors seem to have a pretty smooth "cog/tick" feel to them but it is there, just not nearly as distinct.

Any help would be much appreciated. Thanks,

Jerry

I know what you mean by the feel, but I don't know what to call it.
I guess you could vibration test & fly the new motors and see how Solo performs.

 

[Del]

Hey Folks,

I purchased 4 new Solo motors with pods attached. I was somewhat concerned about one of my old motors and decided to buy 4 so I could start a small inventory of Solo parts. (It can take quite a while to get parts from China.) The questionable motor had a different pitch than the other 3, was quite a bit different in the vibration test graph using the vibrate app with MP and when slowly turning it by hand was quite smooth. The other 3 had a more pronounced "cog" or "tick" feel to them.

I received the new motors a couple of days ago. Upon inspection the new motors seemed to have an even more pronounced "cog/tick". Because of this I assumed the more pronounced "cog/tick" was due to the fact that they were brand new. I had also read that they may have made the newer motors a bit better than the first iteration. I decided that I'd go ahead and replace all 4 and keep my used ones for backup.

I went about installing the new pods (quite easily, I might add!). When I got to the last new pod I noticed it had that smooth feel to it as well. The other 3 had a very distinct "cog/tick" to them. I really wanted these motors to be consistent across all four, so at this point I took one of my old motors with the more distinct "cog/tick" and used it to replace the last motor. (and yes, I was careful to insure it was the proper direction!)

I guess the question/information I'm looking for is how should these motors feel? smooth or with the more distinct "cog/tick"? Would you do as I did or would you replace the last one with the new smooth one anyway? Sorry for the lack of correct terminology, as you can tell my experience with electric motors is subpar. My other multi rotors seem to have a pretty smooth "cog/tick" feel to them but it is there, just not nearly as distinct.

Any help would be much appreciated. Thanks,

Jerry

Sorry I'm late..lol
Wanted to jump into this thread a while ago but didint have the time!

But I always was curious what that means when you spin your motors with your fingers and feeling a the difference in the "cog/tick" as Jerry the way he explains on all 4 motors?
Is a stronger "cog/tick" feeling when spinning motor with your fingers good or bad?

Well I grabbed a beer and my Solo and put Solo on my coffee table...
Spun All 4 motored with my fingers...my #2 motor spun with the least
resistance "cog/tick"....!! It spins pretty freely compared to my other three motors !!

But now here's where it gets interesting ..

When I did a vibration test on all 4 motors ...my #2 motor with the least resistance "cog/tick" also has the least vibration !!! So basically telling me that #2 is the healthier motor ??




Cheers

 

[Mauiwind]

this cog/tick does not mean it's sick. Leftover electricity makes them subject to the magnets..... do some research...

 

[pyrate]

Question is what to do with pods with too much vibration in them?
can you buy the motors from someone, stock ones? do you rebuild them with new bearings?
I think I am going to write 3DR and let them know I had to replace two pods for vibration and see what they recommend

 

[J R]

Thanks for the replies guys! Mauiwind, thanks for absolutely nothing. And here they come...

Jerry

 

[Maddog]

Question is what to do with pods with too much vibration in them?
can you buy the motors from someone, stock ones? do you rebuild them with new bearings?
I think I am going to write 3DR and let them know I had to replace two pods for vibration and see what they recommend

I think SteveReno has a thread going where he bought new bearings and rebuilt his motors. I'll see if I can find it.

 

[Maddog]

this cog/tick does not mean it's sick. Leftover electricity makes them subject to the magnets..... do some research...

Why don't you share what you know about the subject or point the OP to a specific source of information?

Just telling somebody to "do some research" is rude and childish.
Next time you ask for help you may just reap what you've sown..

 

[RolandS888]

Jerry,
the magnetic cogging differences between the motors is curious. I have this happening amongst the 4 motors I have removed from my solo. I dont understand why there are differences and I dont think there should be any.
It has nothing to do with the electronics they are connected to because my motors are completely disconnected (unsoldered) and they still have the same cogging differences.
Even when they are in the pods, the N-FETS that switch the current in the ESCs are very high resistance when turned off and are effectively open circuit. (Nothing to do with "left over electricity", LOL)
The cogging is caused by the 14 magnets in the rotor (the bell) being attracted to the 12 wire wound 'poles' of the motor stator (the middle bit).
In some places in the rotors rotation, a magnets will line up with a pole and there will be attraction causing some resistance to being turned by hand, in other places no magnets line up with poles and there is less resisitance to turning by hand. This situation is coming and going as you rotate a motor by hand and that is what you feel as 'cogging' as you rotate a motor.
The magnets in the rotor should be alternating north and south faces, so around the rotor there should be N.S.N.S.N.S. etc for the 14 magnets.
Why there is a difference in Solos case between mass produced motors in such a small sample group is puzzling, and begs the thought that there is a quality control issue here.
When I replaced my motors with the T-motor 2216s, I bought 5 of them, they have less severe cogging, they still have it, but it is higher resolution and consistant amongst all 5, even though the T-motors I bought have the same number of poles and magnets as the stock solo motors.
The stock motors are supposed to be supplied by T-motor, and that may well be the case, but I struggle to believe that T-motor produced them, given the inconsistancies in production and the imperial bearing and shaft sizes..
I have a theory Id like to test (when Im back - mid next week) is to test the polarity of the magnets inside the rotor of the motors I have removed from Solo. Especially the ones that cogg more coursely.
I am wondering whether there might be a S.N.S.S.N.S.N.S error or even S.N.N.N.S.N.S.N in amongst the magnets. This could cause rougher cogging, but its only a hunch at this stage, and will remain that way until I can test it next week.
Its easy to make this kind of mistake if these rotor bells are assembled by hand. I used to build and wind my own brushless motors 15 years ago, but thats a whole other story, suffice to say those little magnets are really strong and its not hard to make an error on installation..
I also will also soon have some 'rejected' solo motor pods that I bought off ebay, the seller bought 2 new replacements because these two had too much vibration. I primarily bought them for the pods, but it will be interesting to autopsy the motors and hopefully get to the bottom of what is going on with the inconsistant magnetic cogging and vibes, I'll post my finding here of course, in the (cough...) technical section.

In answer to your question Jerry, I would initially go for 4 smooth motors (if you have 4 of them) if not, I would install 4 that are the same. If they do indeed have a characteristic that is causing a difference it is probably better to have that characteristic in all 4 at the same time.
That way the flight controller wont have to cope with "different" motors. Although, as we have all seen, the pixhawk copes very well with the stock motors just the way they are.
Simplistically put, a smoother cogging motor will draw less current at no load, and this no load current is a constant impost all the way through its rev range when loaded.

This is all personal opinion from what I have learnt over the years, and that being the case, I may be completely wrong, mistaken, and misled.(But I dont think so )

 

[Del]

Jerry,
the magnetic cogging differences between the motors is curious. I have this happening amongst the 4 motors I have removed from my solo. I dont understand why there are differences and I dont think there should be any.
It has nothing to do with the electronics they are connected to because my motors are completely disconnected (unsoldered) and they still have the same cogging differences.
Even when they are in the pods, the N-FETS that switch the current in the ESCs are very high resistance when turned off and are effectively open circuit. (Nothing to do with "left over electricity", LOL)
The cogging is caused by the 14 magnets in the rotor (the bell) being attracted to the 12 wire wound 'poles' of the motor stator (the middle bit).
In some places in the rotors rotation, a magnets will line up with a pole and there will be attraction causing some resistance to being turned by hand, in other places no magnets line up with poles and there is less resisitance to turning by hand. This situation is coming and going as you rotate a motor by hand and that is what you feel as 'cogging' as you rotate a motor.
The magnets in the rotor should be alternating north and south faces, so around the rotor there should be N.S.N.S.N.S. etc for the 14 magnets.
Why there is a difference in Solos case between mass produced motors in such a small sample group is puzzling, and begs the thought that there is a quality control issue here.
When I replaced my motors with the T-motor 2216s, I bought 5 of them, they have less severe cogging, they still have it, but it is higher resolution and consistant amongst all 5, even though the T-motors I bought have the same number of poles and magnets as the stock solo motors.
The stock motors are supposed to be supplied by T-motor, and that may well be the case, but I struggle to believe that T-motor produced them, given the inconsistancies in production and the imperial bearing and shaft sizes..
I have a theory Id like to test (when Im back - mid next week) is to test the polarity of the magnets inside the rotor of the motors I have removed from Solo. Especially the ones that cogg more coursely.
I am wondering whether there might be a S.N.S.S.N.S.N.S error or even S.N.N.N.S.N.S.N in amongst the magnets. This could cause rougher cogging, but its only a hunch at this stage, and will remain that way until I can test it next week.
Its easy to make this kind of mistake if these rotor bells are assembled by hand. I used to build and wind my own brushless motors 15 years ago, but thats a whole other story, suffice to say those little magnets are really strong and its not hard to make an error on installation..
I also will also soon have some 'rejected' solo motor pods that I bought off ebay, the seller bought 2 new replacements because these two had too much vibration. I primarily bought them for the pods, but it will be interesting to autopsy the motors and hopefully get to the bottom of what is going on with the inconsistant magnetic cogging and vibes, I'll post my finding here of course, in the (cough...) technical section.

In answer to your question Jerry, I would initially go for 4 smooth motors (if you have 4 of them) if not, I would install 4 that are the same. If they do indeed have a characteristic that is causing a difference it is probably better to have that characteristic in all 4 at the same time.
That way the flight controller wont have to cope with "different" motors. Although, as we have all seen, the pixhawk copes very well with the stock motors just the way they are.
Simplistically put, a smoother cogging motor will draw less current at no load, and this no load current is a constant impost all the way through its rev range when loaded.

This is all personal opinion from what I have learnt over the years, and that being the case, I may be completely wrong, mistaken, and misled.(But I dont think so )

Thanks for the great Post Roland and taking the time Sharing your knowledge your experience and thoughts on the motors! That was very interresting to read..you just made me undertsand a lot more about the motors!

Iv notice I high rate of solo crashes are do to Bad Motors!
I'm just wondering Why is this happening...? Did 3DR make a bad Batch? And what exactly is failing in these motors ..is it electrical or mechanical ?


Cheers

this cog/tick does not mean it's sick. Leftover electricity makes them subject to the magnets..... do some research...

Doing some research ....
Solo motor and pod info sought... | 3D Robotics Drone Forum

 

[J R]

Jerry,
the magnetic cogging differences between the motors is curious.

Roland,

Thank you very much for such a thoughtful reply. Your description and explanation was extremely helpful to me. I now understand what causes this clogging. Although I understood the basic components, I never understood what's actually occurring. That's what I'm here for, to learn! And hopefully help a few others along the way. I always look forward to reading your posts as you always provide insightful information.

It is amazing that with eight motors in front of me they were so inconsistent. My thought when installing them was similar to your conclusion. To try to keep them as consistent as possible. I ended up installing four with the most "cog/tick". As Del also noted in one of his previous posts, the "smoother" ones seemed to test the best in the vibration tests. Unfortunately, I only had three "smooth" ones.

That being said, I also installed (if you can call it that) my new FPVLR setup. I put the bird in the cold air (25F) yesterday and successfully ran through six batteries. I ran four Tower tests around my property with five ROI's and various circle waypoint, up to 500' in circumference. Each Tower run at over two miles. Everything went well with no real hiccups and I finally got a good look at what I can expect from my new 4.3mm Peau camera setup.

So at this point all looks good but I'd really like to keep tweaking the performance from this bird without doing any dramatic mods. If I was more confident in my soldering skills, I'd do the T-Motor mod in a minute. I'm not confident enough in my abilities and those puppies ain't cheap so I don't dare take a chance on screwing it up.

Thanks again for your insightful post!

Jerry

 

[pyrate]

3dr sent me an RMA for my bad motors after I explained why I replaced them

 

[Maddog]

Jerry,
the magnetic cogging differences between the motors is curious. I have this happening amongst the 4 motors I have removed from my solo. I dont understand why there are differences and I dont think there should be any.
It has nothing to do with the electronics they are connected to because my motors are completely disconnected (unsoldered) and they still have the same cogging differences.
Even when they are in the pods, the N-FETS that switch the current in the ESCs are very high resistance when turned off and are effectively open circuit. (Nothing to do with "left over electricity", LOL)
The cogging is caused by the 14 magnets in the rotor (the bell) being attracted to the 12 wire wound 'poles' of the motor stator (the middle bit).
In some places in the rotors rotation, a magnets will line up with a pole and there will be attraction causing some resistance to being turned by hand, in other places no magnets line up with poles and there is less resisitance to turning by hand. This situation is coming and going as you rotate a motor by hand and that is what you feel as 'cogging' as you rotate a motor.
The magnets in the rotor should be alternating north and south faces, so around the rotor there should be N.S.N.S.N.S. etc for the 14 magnets.
Why there is a difference in Solos case between mass produced motors in such a small sample group is puzzling, and begs the thought that there is a quality control issue here.
When I replaced my motors with the T-motor 2216s, I bought 5 of them, they have less severe cogging, they still have it, but it is higher resolution and consistant amongst all 5, even though the T-motors I bought have the same number of poles and magnets as the stock solo motors.
The stock motors are supposed to be supplied by T-motor, and that may well be the case, but I struggle to believe that T-motor produced them, given the inconsistancies in production and the imperial bearing and shaft sizes..
I have a theory Id like to test (when Im back - mid next week) is to test the polarity of the magnets inside the rotor of the motors I have removed from Solo. Especially the ones that cogg more coursely.
I am wondering whether there might be a S.N.S.S.N.S.N.S error or even S.N.N.N.S.N.S.N in amongst the magnets. This could cause rougher cogging, but its only a hunch at this stage, and will remain that way until I can test it next week.
Its easy to make this kind of mistake if these rotor bells are assembled by hand. I used to build and wind my own brushless motors 15 years ago, but thats a whole other story, suffice to say those little magnets are really strong and its not hard to make an error on installation..
I also will also soon have some 'rejected' solo motor pods that I bought off ebay, the seller bought 2 new replacements because these two had too much vibration. I primarily bought them for the pods, but it will be interesting to autopsy the motors and hopefully get to the bottom of what is going on with the inconsistant magnetic cogging and vibes, I'll post my finding here of course, in the (cough...) technical section.

In answer to your question Jerry, I would initially go for 4 smooth motors (if you have 4 of them) if not, I would install 4 that are the same. If they do indeed have a characteristic that is causing a difference it is probably better to have that characteristic in all 4 at the same time.
That way the flight controller wont have to cope with "different" motors. Although, as we have all seen, the pixhawk copes very well with the stock motors just the way they are.
Simplistically put, a smoother cogging motor will draw less current at no load, and this no load current is a constant impost all the way through its rev range when loaded.

This is all personal opinion from what I have learnt over the years, and that being the case, I may be completely wrong, mistaken, and misled.(But I dont think so )

Thanks for the great info!
With all that in mind, would stronger magnets make a more pronounced "cog-tic feel"? Do stronger magnets make for a more powerful motor?

Also, where did you get your T- motors, and did they make a noticible improvement in Solos handling? Or did you replace them just for increased reliability?

 

[RichWest]

I am wondering whether there might be a S.N.S.S.N.S.N.S error or even S.N.N.N.S.N.S.N in amongst the magnets. This could cause rougher cogging, but its only a hunch at this stage, and will remain that way until I can test it next week.

I checked my motor's polarity and they were correctly installed...N.S.N.S.N.S. That was my theory as well, but wasn't the offender.

We can discuss Cogging Torque, but the question would still be a better balanced motor. Balance refers to cogging and run out, resolve those and you have less of an issue related to vibration. We can resolve balance, but we can't easily resolve cogging. Cogging is a part of the manufacturing processes. Magnets, I would assume are the main offender and the shaft plays second. You'd have to remove the magnets from the bell to even have a fighting chance in reducing cogging. I'd go with 3mm shafts if I was replacing them. In the end is the effort worth it....?

We just need a more consistent product from the get go. And by all conversation it appears to be the CW motors are the majority of the issues. Replacing with OEM pods is hit or miss, in my experience it has been 50/50 for a better product. I'd like 3DR to resolve by specifying better control for what is acceptable, the current specs falls short.

I for one am looking forward to Roland's T-motor swap results. I really think it is the only solution at this time. We could play the 50/50 game under RMA and still be no where better. Shame on you 3DR!

This is all personal opinion from what I have learnt over the years, and that being the case, I may be completely wrong, mistaken, and misled.(But I dont think so )

I vote that you're right....

 

[RolandS888]

Thanks @RichWest Im looking forward to fully testing those T motors too, (still a few days away)

 

[XperienceVisuals]

Just swapped out 3 motors and finally have a complete smooth set. 2 still sound off though. I will say the cogging feels the same across the board and is smoother and less pronounced than the 3 that got replaced. Kind of a pain but 3DR was more than helpful thru the whole process. Also curious about the T Motors.

 

[Mauiwind]

Why don't you share what you know about the subject or point the OP to a specific source of information?

Just telling somebody to "do some research" is rude and childish.
Next time you ask for help you may just reap what you've sown..

OK, I apologise, let me try to find a decent explain:
I really DO apologize, you're 1000% correct.
This fellow and his channel is a wealth of information.

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[J R]

OK, I apologise, let me try to find a decent explain:
I really DO apologize, you're 1000% correct.
This fellow and his channel is a wealth of information.

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For more detailed information, see our cookies page.

Accept third party cookies

Maui,

Thank you for the very helpful info. I'm just learning this stuff so any info is good info for me at this point! The issue for me has been this cogging with absolutely no power provided to the motor. The replacements I received were in transit for three weeks and when removed from the packaging one in particular was much smoother than the other three. I experienced the variations in the cogging on my old motors with absolutely no power to them for extended periods of time. I think Roland and Rich have nailed it as a "loose" manufacturing process. Out of 8 motors only 5 of the 8 (new and old) are what I'd consider consistent by hand turning. I'm sure hand turning is not a very scientific approach but it's enough to make my assessment.

I think Maddog brings up a good question, which is better, more resistance or less? If more is better then 5 of 8 motors are okay. If smooth is better than 3 of 8 motors are okay. In either case the percentage of "good" motors would be considered unacceptable. If it's 3 out of 8 that's a huge problem. Really, either one is a huge problem. Just my very uneducated opinion, of course.

I am learning though and that's the most important thing for me! Thanks for the information!

Jerry

 

[Doug Benson]

this cog/tick does not mean it's sick. Leftover electricity makes them subject to the magnets..... do some research...

We are here to "LEARN" & "SHARE" Knowledge, are we not?

 

[RichWest]

I think Maddog brings up a good question, which is better, more resistance or less?

The "smoother" the motor the better. Heavy cogging is a failure when the magnetic/mechanical pull is stronger rather than lighter, at least for our motors. We can only make a motor so light in felt cogging, if built properly. The pull felt is directly connected to how smooth the motor will run or slow down. Most people can understand how a gas engine feels if a cylinder is not firing properly, we basically have a magnet(s) that is not firing correctly in our motors. Fix or replace the motor and then we can better manage vibration.

Further, the ESC is configured to run a properly built motor, within specified tolerances. When we have an out of spec motor using the same settings we should expect irregular operation. Again higher induced vibration and at a different frequency. Software tweaking can only remedy so much....

I mentioned in my motor balance thread that I have an IEEE document discussing cogging torque with brushless motors for high volume production motors. It explains the various causes and the effects it has on the motor and the connected components, again it relates to vibration as the impact. Needless to say the paper was written on how to reduce cogging torque from production motors rather than increasing it....

@Mauiwind I like the guy's videos, seen several and he appears to understand much about the overall systems. His example in the video were higher kV motors with lower mass and I would agree with his example provided. I'm fairly certain however his example is much less pronounced in our motors with a lower kV rating and heavier mass. Either way his video was informative for how the ESC effects the static brushless motors based on residual voltage.

So what is the solution? @Vu.3DR do you have any input to what we are discussing? Are we all mis-guided in our assessments? Possibly you have a real Engr available to enlighten us. I can vouch for the members participating in this thread as bona fide 3DR propeller heads....