Bad brushless motor?

Michael Fenimore

Michael Fenimore

Well-Known Member
So being the ex-grease monkey that I am, I was changing a prop on my quad and while tightening it back up, I twisted the shaft off. DOH!
So, I ordered 4 new motors. YKS 1806-2300kv.
At the same time I ordered new ESCs.
Once I got everything in place and programmed with LibrePilot I did a quick test flight.
I noticed that one of the motors seems to lag behind the others when it decelerates.
All the others spin down just fine.
Here's a short video of what I'm trying to describe. :)
So my question is: Is the motor bad? Is it the ESC?
I've done some poking around on the internetz and haven't found any definitive answers.

I contacted the seller on Amazon and they are giving me a credit for the cost of one motor.
Better than nothing I suppose.

If anyone has any suggestions or experience with this type of problem, I could really use your 'expertise' here. :)

Thanks in advance.

- Mike
 
Jackson said:
First check the screw length.
http://www.droneracer.uk/2015/02/droneracer-build-log-attaching-motors.html
Click to expand...

Not being certain, I removed the screws and compared them to the others.
They are all the same length. Since they were removed from the offending motor, I spun them up and it does the same thing.
It still functions, but my concern is that if/when I release throttle all the way, that motor will spin down faster and cause the flight characteristics to be uneven.
With that said, I have already ordered 4 new motors ... again. This time Emax 2204-2300kv. Along with their 20A ESCs.

So now I will have 6 good motors. One iffy one and one with no prop shaft. ;)
I guess that's one way to start a collection of various parts lol

Thanks Jackson.
 
Michael Fenimore said:
So being the ex-grease monkey that I am, I was changing a prop on my quad and while tightening it back up, I twisted the shaft off. DOH!
So, I ordered 4 new motors. YKS 1806-2300kv.
At the same time I ordered new ESCs.
Once I got everything in place and programmed with LibrePilot I did a quick test flight.
I noticed that one of the motors seems to lag behind the others when it decelerates.
All the others spin down just fine.
Here's a short video of what I'm trying to describe. :)
So my question is: Is the motor bad? Is it the ESC?
I've done some poking around on the internetz and haven't found any definitive answers.

I contacted the seller on Amazon and they are giving me a credit for the cost of one motor.
Better than nothing I suppose.

If anyone has any suggestions or experience with this type of problem, I could really use your 'expertise' here. :)

Thanks in advance.

- Mike
Click to expand...
Excessive screw length causes twitching or no spinning as it breaks the circuit in the coil(s). I happen to have ruined 4 motors that way :(.


It looks almost like active breaking, which can usually be turned on and off in the ESC's firmware. Sometimes companies will ship a batch of ESCs and you will get a couple or so that are older or newer were configured differently for whatever reason. To test this swap the motor that is stopping faster with one that continues. Does the problem follow the motor or stay with the ESC? If it stays with the ESC then that is probably your problem. Otherwise it may be a mechanical problem with a motor.
 
GJH105775 said:
Excessive screw length causes twitching or no spinning as it breaks the circuit in the coil(s). I happen to have ruined 4 motors that way :(.


It looks almost like active breaking, which can usually be turned on and off in the ESC's firmware. Sometimes companies will ship a batch of ESCs and you will get a couple or so that are older or newer were configured differently for whatever reason. To test this swap the motor that is stopping faster with one that continues. Does the problem follow the motor or stay with the ESC? If it stays with the ESC then that is probably your problem. Otherwise it may be a mechanical problem with a motor.
Click to expand...


That's my next step. To try the motor on a different ESC.
I also thought of the braking scenario, but I am not sure if the present ESCs are flashable. I'm sure they are, but I don't know how.
/EDIT
The ESCs are
HobbyWing Flyfun ESC 12AE from Amazon
http://www.amazon.com/HobbyWing-Fly...&redirect=true&ref_=oh_aui_detailpage_o04_s00
/End
I'm using a CC3D FC and FS-iA6B rx. This combo is set for PPM.
I don't remember seeing an area about braking in LP.

Thanks for the suggestion. I'll let you know.
 
Jackson said:
Good call.

FWIW have you tried to fly it? I'd be tempted to try a punch out, and see if it flys straight up evenly..
Click to expand...

No I haven't tried to fly it yet. I probably will now as a test.
But it will have to wait until next week. I'm out of town as of tomorrow.
I'll post some results as soon as I can.
 
Michael Fenimore said:
That's my next step. To try the motor on a different ESC.
I also thought of the braking scenario, but I am not sure if the present ESCs are flashable. I'm sure they are, but I don't know how.
/EDIT
The ESCs are
HobbyWing Flyfun ESC 12AE from Amazon
http://www.amazon.com/HobbyWing-Fly...&redirect=true&ref_=oh_aui_detailpage_o04_s00
/End
I'm using a CC3D FC and FS-iA6B rx. This combo is set for PPM.
I don't remember seeing an area about braking in LP.

Thanks for the suggestion. I'll let you know.
Click to expand...
Most all ESCs are flashable, but proceed with caution when doing so. A bad or incorrupt firmware can cause the FETs to lock and burn both the motors and ESCs. Your biggest problem would probably be present when dropping your throttle on decent. It may cause oscillations as the other motors slow to the speed of one with the breaking.

Like Jackson said, probably would not hurt to do a test flight if you swap motors and verify that it is the ESC .
 
Update:
The programming card for the ESCs arrived yesterday and I checked the programming for each ESC.
2 of the 4 were in braking mode. After releasing that setting I checked the spin of the offending motor.
It does spin more freely on deceleration now, but still seems to "stick" just a little when it reaches or gets close to zero RPM.
Either way, it does react better than it did before.
No chance to fly it yet. But that will happen today. :)

Thanks everyone for tips and ideas.
 
Jackson said:
Click to expand...
Interesting you posted this. :)
I viewed that one just last week in my search for information on my scenario.
As it stands now, since the motor is reacting more or less like all the others, I'm leaning toward the programming of the ESC being the culprit.
But I've got a lot of work (rewiring, placement, addition of FPV cam, OSD and new Matek PDB, etc) to complete and then do a thorough test.
Also, I received 4 new motors and 4 new ESCs (Emax 2204-2300kv and Emax SimonK 12A ESCs)
I'm going to complete the build with what I have on board now and if that doesn't satisfy my issues, then I will replace everything re: motors and ESCs.

Times like this I'm almost glad not having a spouse or someone else to explain my spending on all this stuff LOL

Thanks Jackson.

- Mike
 
Altsickeness said:
Yeah, I've been getting heat from the spouse. I've switched to amazon gift cards for awhile until the heat dies down. Ha Ha!
Click to expand...
Hahahaha, sounds like you need to get her a little FPV quad going in hopes of getting her into the addiction. If not there are always means of making stuff just appear ;)
 
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