I'm glad I watched your video instead of buying a new motor. A guy at my local hobby shop said that my motor felt tight with the spur gear off. It was kinda tight but it moved smoothly. No ticking or skipping. You saved me $150
Bro!! this helped a ton.. I have 2 slashes and 2 bandits that run super smooth.. I bought a used SC10 from a local pawn shop for a steal as the upgrade parts alone were worth what i paid for it.. It came with a castle 3900 4 pole motor and thought the internals were trashed because it always clicked on accelleration fwd or reverse.. I rebuilt everything and temp swapped ESCs to no avail.. I narrowed it down to having to be the motor after only getting the click when the pinion gear was engaged.. This all makes sense now!! ugh! I am sure you went through my grief at some time too!! Thanks for the thorough explaination!! helped a ton and relieved my OCD tremendously! I love working on things for the simple satisfaction of fixing them and feeling accomplished and this was driving me insane!! Thumbs up! It all makes sense now!
Very helpful, first time I’ve used brushless/ lipo. I thought the noise was my pinion to spur gear mesh ! Couldn’t understand as the car was running fine 👍
My esc fan locked up and it got very hot since then the HEAVY cogging has begun and it doesn't move even with a swift push? ANYONE know what may have happened?
Hy there thanks for all the important infos! I have a question can cogging occur if the engine has been hot and the magnets have lost power? I am asking this because i just bought a used e revo 1/16 and it has a bigging cogging and meanwhile running if i let go of the throttle and throttle again it does a quick cogging and then starts to go further, i am thinking that the esc is searching for the poles a bit and then goes on. Thanks in advance for your answear!
i stumbled on this researching cogging as it might apply to phonographs(record players) that use brushless DC motors. However, these motors don't use separate magnets like you show here. Instead, they use a single round magnet around the 12 pole stator coil. and these motors do not exhibit the physical cogging you demonstrate here. Can you shed any light on this?
Great video as usual! Cogging is a huge issue in the RC Drag Racing and Speed Running communities. Lots of guys jump into insanely high gear ratios trying to get an edge in speed without understanding the relationships between cogging-torque, wheel-torque, ripple voltage, and gearing and end up blowing their ESCs. I've spent a lot of time talking about these issues on my channel and my RC Physics Facebook page. Thanks for helping to get good info out there to the people. Are you on Facebook? I would Love to have you participate in my RC Physics Sandbox group. I'll post a link to this video in there for you.
Hi Thanks for your comment. I'm not experienced with rc drag racing. Sounds like a great example though. Radio control info has a Facebook page. Otherwise I'm rarely on FB. I'll check out your page.
Thanks for the video. I am not too sure if you are right. I always thought that the phenomenon you are talking about is referred to as "torque ripple". This is part of the motor design and depends on strength of magnets, how large the air gap between stator and rotor is and last not least the geometry of the stator (number of slots) and the pole count of the rotor. iI once read a paper about this geometry issue, but it got too complicated for me. so my theory was: we've got torque ripple on the one side, and synchronisation problems on the other side, and the outcome of those two factors leads to cogging: i.e. bad startup habits of the car. What do you think?
Hey Karl, thank you for your comment. The cogging torque is contributing to the torque ripple that you will see in a brushless motor utilizing an iron core. Torque ripple is expressed commonly as a percentage representing the positive and negative variations from the norm. Cogging torque is produced solely from the interaction of the permanent magnet and the iron core. Cogging torque never goes away, however torque ripple can be removed "virtually" by operating the electric motor at very high speeds. You are correct about the motor design parameters you listed. However these are examples of how one could alter the cogging torque of a motor.
I have. A sensored motor with a sensorless esc, and I have 50C discharge lipos, but whenever I try to pull a wheelie on my erevo 2.0 it skips across the pavement. Also, if I get a sensored esc that’s not the same brand as my sensored motor, but I don’t use the sensored cable, will I still have cogging without using the sensor cable
@@RCexplained So as long as the sensor wire is compatible with my esc and motor, and I plug it in, it should stop the cogging? Also i'm planning on getting a Mamba Monster X 6s esc for my erevo 2.0, will I have to buy the series harness to connect the sensor wire if my motor isn't a castle motor(my motor is the Tekin Redline Gen3 T8 1400kv sensored and brushless, and my esc is still the stock Vxl 6s esc)
If you're running a sensored esc it must be connected to the motor or it will not function correctly. You can use a sensored motor with a sensorless esc it just won't be able to utilize the use of the sensors in the motor. Best setup to eliminate the shuddering is to run your sensored motor to a sensored esc and make sure that your drivetrain is free of any binding or restrictions in movement and the your gearing isn't to high for your motor & tire combo (bigger tires then stock) you need to gear down to compensate for the added weight and bigger tires up your gear ratio which will cause a major lag, shudder, or delay when accelerating from a stop.
Using a sensored motor is the only way to fully eliminate any hesitation on startup. Here is how to help improve it. th-cam.com/video/M2k7QloXVNo/w-d-xo.html
Can it be reduced in anyway? I have a brand new hobbywing brushless sensorless combo and it judders for around 2 to 3 seconds before setting off. I sent a friend the video and he said it was cogging. It figures as after its running its perfectly fine. Any ideas from anyone? Car is a hsp 4wd buggy. Flysky controller. All simple kit, building it for my son. Thanks in advance
Hello Christopher. Cogging can not be reduced. This has to do with the design of the motor. However it sounds like what you are experiencing is the ESC having a tough time getting in sync with a sensorless motor. 2 to 3 seconds is a long time until the ESC and motor are in sync with each other. Heres what you can try: -Inspect gear train to be certain there is no binding or unnessary load in the drivetrain. -Be certain the LiPo battery that you are using can supply the current required. (High enough C rating) NiMh batteries contribute to ESC/ motor synchronization problems as they generally can not deliver the power required to get moving. -ensure there is a good connection between the 3 wires from the motor to esc.
@@RCexplained hi thanks for the explanation. I tried many things, but a smaller pinion gear sorted out the issue in the end. Dropped from a 21 to a 17. Lost some top end but it sets of smoothly now and thats nuch more important. Many thanks
@@christopherreding4862 so all you had to do was drop the gearing? I’m having a coughing problem in erevo 2.0 where if I try to pull a wheelie it skips across the road before building up speed
@@RCexplained Do you have any advice for my sensorless and sensored esc and motor combo? I have a stock vxl 6s esc and a tekin redline gen3 1400kv sensored motor. When I try to pull a wheelie in my erevo 2.0 it skips across the concrete, so I have to slowly build up speed. Any tips?
@@doopeygang1923 yes try dropping the gearing. What i noticed was that with higher gearing it would judder with the buggy on the ground, but not with it lifted up in the air. I think the lower gearing creates a little less initial resistance, in my case getting rid of the juddering entirely. I unfortunately have no technical explanation for this! Try playing around with the gearing before investing in new electronics. Chris
Is anyone else having trouble with the Brown sofa, yellow foot stool and grey carpet? I mean the videos brilliant but for the love of god get an interior designer! LOL 😂
Fantastic video. You have put my concerns to rest.
Glad the video could help
I'm glad I watched your video instead of buying a new motor. A guy at my local hobby shop said that my motor felt tight with the spur gear off. It was kinda tight but it moved smoothly. No ticking or skipping. You saved me $150
Hey Thomas, I'm glad that the video was able to help. That is awesome and thank you for leaving a comment!
Please can you give me a little$10 out of the 150😂
Bro!! this helped a ton.. I have 2 slashes and 2 bandits that run super smooth.. I bought a used SC10 from a local pawn shop for a steal as the upgrade parts alone were worth what i paid for it.. It came with a castle 3900 4 pole motor and thought the internals were trashed because it always clicked on accelleration fwd or reverse.. I rebuilt everything and temp swapped ESCs to no avail.. I narrowed it down to having to be the motor after only getting the click when the pinion gear was engaged.. This all makes sense now!! ugh! I am sure you went through my grief at some time too!! Thanks for the thorough explaination!! helped a ton and relieved my OCD tremendously! I love working on things for the simple satisfaction of fixing them and feeling accomplished and this was driving me insane!! Thumbs up! It all makes sense now!
Great video, felt like I was setting in class & listening to a lecture I actually enjoyed. Very well done sir & very informative.
Thank You for the awesome comment!
Very helpful, first time I’ve used brushless/ lipo. I thought the noise was my pinion to spur gear mesh ! Couldn’t understand as the car was running fine 👍
Glad it helped, thanks for the comment!
My esc fan locked up and it got very hot since then the HEAVY cogging has begun and it doesn't move even with a swift push? ANYONE know what may have happened?
Hy there thanks for all the important infos!
I have a question can cogging occur if the engine has been hot and the magnets have lost power? I am asking this because i just bought a used e revo 1/16 and it has a bigging cogging and meanwhile running if i let go of the throttle and throttle again it does a quick cogging and then starts to go further, i am thinking that the esc is searching for the poles a bit and then goes on.
Thanks in advance for your answear!
Yes however you can measure kv to determine if the motor was damaged.
i stumbled on this researching cogging as it might apply to phonographs(record players) that use brushless DC motors. However, these motors don't use separate magnets like you show here. Instead, they use a single round magnet around the 12 pole stator coil. and these motors do not exhibit the physical cogging you demonstrate here. Can you shed any light on this?
i have several E-Flite BL outrunners in my RC aircraft that have 12 windings (6 pole) but 14 magnets. How the heck does THAT work out???
Excellent video!
Thank you Bay Area FPV!
Great video as usual! Cogging is a huge issue in the RC Drag Racing and Speed Running communities. Lots of guys jump into insanely high gear ratios trying to get an edge in speed without understanding the relationships between cogging-torque, wheel-torque, ripple voltage, and gearing and end up blowing their ESCs. I've spent a lot of time talking about these issues on my channel and my RC Physics Facebook page.
Thanks for helping to get good info out there to the people. Are you on Facebook? I would Love to have you participate in my RC Physics Sandbox group. I'll post a link to this video in there for you.
Hi Thanks for your comment. I'm not experienced with rc drag racing. Sounds like a great example though.
Radio control info has a Facebook page. Otherwise I'm rarely on FB. I'll check out your page.
@@RCexplained I found and liked you page. Later!
Very good presentation!
Thank you kindly!
great video, thank you!
Thank you for the comment Red hulk!
Nice video. Very informative
Thank you!
Thanks for the video.
I am not too sure if you are right. I always thought that the phenomenon you are talking about is referred to as "torque ripple". This is part of the motor design and depends on strength of magnets, how large the air gap between stator and rotor is and last not least the geometry of the stator (number of slots) and the pole count of the rotor. iI once read a paper about this geometry issue, but it got too complicated for me.
so my theory was: we've got torque ripple on the one side, and synchronisation problems on the other side, and the outcome of those two factors leads to cogging: i.e. bad startup habits of the car.
What do you think?
Hey Karl, thank you for your comment. The cogging torque is contributing to the torque ripple that you will see in a brushless motor utilizing an iron core. Torque ripple is expressed commonly as a percentage representing the positive and negative variations from the norm. Cogging torque is produced solely from the interaction of the permanent magnet and the iron core. Cogging torque never goes away, however torque ripple can be removed "virtually" by operating the electric motor at very high speeds.
You are correct about the motor design parameters you listed. However these are examples of how one could alter the cogging torque of a motor.
Dang… amazing. Now I know exactly why my stampede is cogging! Because my stampede failed mechanical and electrical engineering class. LMAO
I have. A sensored motor with a sensorless esc, and I have 50C discharge lipos, but whenever I try to pull a wheelie on my erevo 2.0 it skips across the pavement. Also, if I get a sensored esc that’s not the same brand as my sensored motor, but I don’t use the sensored cable, will I still have cogging without using the sensor cable
you need a cable to connect the sensors in the motor to the ESC
@@RCexplained So as long as the sensor wire is compatible with my esc and motor, and I plug it in, it should stop the cogging? Also i'm planning on getting a Mamba Monster X 6s esc for my erevo 2.0, will I have to buy the series harness to connect the sensor wire if my motor isn't a castle motor(my motor is the Tekin Redline Gen3 T8 1400kv sensored and brushless, and my esc is still the stock Vxl 6s esc)
If you're running a sensored esc it must be connected to the motor or it will not function correctly. You can use a sensored motor with a sensorless esc it just won't be able to utilize the use of the sensors in the motor. Best setup to eliminate the shuddering is to run your sensored motor to a sensored esc and make sure that your drivetrain is free of any binding or restrictions in movement and the your gearing isn't to high for your motor & tire combo (bigger tires then stock) you need to gear down to compensate for the added weight and bigger tires up your gear ratio which will cause a major lag, shudder, or delay when accelerating from a stop.
Is there anyway to stop the cogging?
Using a sensored motor is the only way to fully eliminate any hesitation on startup. Here is how to help improve it. th-cam.com/video/M2k7QloXVNo/w-d-xo.html
@@RCexplained thank you!
Can it be reduced in anyway? I have a brand new hobbywing brushless sensorless combo and it judders for around 2 to 3 seconds before setting off. I sent a friend the video and he said it was cogging. It figures as after its running its perfectly fine. Any ideas from anyone? Car is a hsp 4wd buggy. Flysky controller. All simple kit, building it for my son. Thanks in advance
Hello Christopher. Cogging can not be reduced. This has to do with the design of the motor. However it sounds like what you are experiencing is the ESC having a tough time getting in sync with a sensorless motor. 2 to 3 seconds is a long time until the ESC and motor are in sync with each other.
Heres what you can try:
-Inspect gear train to be certain there is no binding or unnessary load in the drivetrain.
-Be certain the LiPo battery that you are using can supply the current required. (High enough C rating) NiMh batteries contribute to ESC/ motor synchronization problems as they generally can not deliver the power required to get moving.
-ensure there is a good connection between the 3 wires from the motor to esc.
@@RCexplained hi thanks for the explanation. I tried many things, but a smaller pinion gear sorted out the issue in the end. Dropped from a 21 to a 17. Lost some top end but it sets of smoothly now and thats nuch more important. Many thanks
@@christopherreding4862 so all you had to do was drop the gearing? I’m having a coughing problem in erevo 2.0 where if I try to pull a wheelie it skips across the road before building up speed
@@RCexplained Do you have any advice for my sensorless and sensored esc and motor combo? I have a stock vxl 6s esc and a tekin redline gen3 1400kv sensored motor. When I try to pull a wheelie in my erevo 2.0 it skips across the concrete, so I have to slowly build up speed. Any tips?
@@doopeygang1923 yes try dropping the gearing. What i noticed was that with higher gearing it would judder with the buggy on the ground, but not with it lifted up in the air. I think the lower gearing creates a little less initial resistance, in my case getting rid of the juddering entirely. I unfortunately have no technical explanation for this! Try playing around with the gearing before investing in new electronics.
Chris
thank you
Is anyone else having trouble with the Brown sofa, yellow foot stool and grey carpet? I mean the videos brilliant but for the love of god get an interior designer! LOL 😂
LOL, no, I don't think anyone did.
@RCexplained There are far more important things than matching furniture my friend ;) have a good one! :)
Its an old place. Not there anymore. You'll have to watch some newer videos.
@@RCexplained Will do Ryan while I am rendering out a video for TH-cam. Working on an epic 1/8th Scale Crawler review, the video is beautiful! 😁
@The_RC_Daddy very nice. Sounds great!
This is practically all wrong.
I'd like to know why you think this is wrong. Please explain why.
Great video, thx.
Glad you liked it!