Single motor very hot.

[fizzlefish]

One of my back motors on my Mavic is getting very very hot. Too hot to keep my finger on without getting burned. I am using brand new props and even switched them around. While it is a bit windy I would think I would have more than just a single motor this hot. All other motors are actually cool to the touch. Just worried about the motor failing mid flight. Anyone else having issue with motor heat? Thanks.

 

[BD0G]

There is more than likely too much resistance on that motor or a bad ESC -Electronic Speed Controller (internally). Check that it spins freely with no power to the MAvic and the propeller removed.

Dont chance this and open a support ticket with DJI.

 

[Wombat55]

One of my back motors on my Mavic is getting very very hot. Too hot to keep my finger on without getting burned. I am using brand new props and even switched them around. While it is a bit windy I would think I would have more than just a single motor this hot. All other motors are actually cool to the touch. Just worried about the motor failing mid flight. Anyone else having issue with motor heat? Thanks.

How did you first find out or suspect that this motor was running hot? Putting one's fingers on the Mavic's motors while they are spinning high-speed propellers is not a natural act. Was there some reason that you were testing the temperature of this and the other motors such as a recent crash?

 

[fizzlefish]

How did you first find out or suspect that this motor was running hot? Putting one's fingers on the Mavic's motors while they are spinning high-speed propellers is not a natural act. Was there some reason that you were testing the temperature of this and the other motors such as a recent crash?

... It was not spinning. I touched it when folding it up to put it away...

 

[BD0G]

Good question. Wombat55. Was the one motor making a strained noise or clicking?

 

[fizzlefish]

Nothing out of the ordinary at all. No bent shaft, not dirt or anything to throw off the balance. No odd noise.

 

[Wombat55]

... It was not spinning. I touched it when folding it up to put it away...

So this was a one-time observation, or did you confirm that this particular motor consistently runs hot with respect to the other motors? The reason that I'm asking this is that the motors of a quadcopter such as a Mavic actually do a lot more work than many people realize. The quadcopter's control electronics are constantly adjusting and re-adjusting the speeds of the propellers many times per second in order to keep the quadcopter in level flight. And depending on the wind direction it's conceivable that one of the motors (for example, the downwind-most motor or the upwind-most motor) might have to work a bit harder than the other motors in keeping the aircraft stabilized. So if you haven't done it already, I would re-check whether that particular motor always runs hot if the Mavic is launched, hovers, and then lands at various fixed Mavic orientations with respect to the wind direction.

 

[integlikewhoa]

I would have guess a prop problem, but you already swapped them.

If the lift is lower on one corner of the quad that motor has to work harder and spin faster to maintain the same lift as the others to stay level in flight. This will cause that motor to over work and run hotter then the rest. Usually when I had this problem (other quads not dji) I found a cracked or damaged prop. But motor failure would be the next thing if you can't seem to find a prop issue.

I would ofcourse say try a factory DJI prop and report back.

 

[cruisinforgold]

Nothing out of the ordinary at all. No bent shaft, not dirt or anything to throw off the balance. No odd noise.

Check each motor with an IR thermometer and report back the differences after running a bit on the ground.

 

[fizzlefish]

So this was a one-time observation, or did you confirm that this particular motor consistently runs hot with respect to the other motors? The reason that I'm asking this is that the motors of a quadcopter such as a Mavic actually do a lot more work than many people realize. The quadcopter's control electronics are constantly adjusting and re-adjusting the speeds of the propellers many times per second in order to keep the quadcopter in level flight. And depending on the wind direction it's conceivable that one of the motors (for example, the downwind-most motor or the upwind-most motor) might have to work a bit harder than the other motors in keeping the aircraft stabilized. So if you haven't done it already, I would re-check whether that particular motor always runs hot if the Mavic is launched, hovers, and then lands at various fixed Mavic orientations with respect to the wind direction.

I have replicated this twice now with different props. Though it is windy outside and was just hovering in the same spot and orientation. Only had enough juice left in the lipo to check again really fast with different props. I am charging it back up now to try again. Will report back. I do know that these brushless motors are constantly changing speeds and adjusting to keep the craft levels. I have only had motors this hot on my race quads and have not experienced this on the Mavic until now. Or just have not noticed it until now.

 

[Wombat55]

I have replicated this twice now with different props. Though it is windy outside and was just hovering in the same spot and orientation. Only had enough juice left in the lipo to check again really fast with different props. I am charging it back up now to try again. Will report back. I do know that these brushless motors are constantly changing speeds and adjusting to keep the craft levels. I have only had motors this hot on my race quads and have not experienced this on the Mavic until now. Or just have not noticed it until now.

The fact that it is windy is consistent with the hypothesis that one of the motors might have to be working much harder than the others in order to keep the aircraft stabilized. If you aren't able to immediately do a flight test under conditions of no or little wind, then I would try to make sure that the next time you fly that the Mavic is pointed in a different direction with respect to the wind (and stays pointed in the same direction with respect to the wind throughout its short up-and-down flight test).

BTW, did the hot motor of your previous flight test have any particular position with respect to the wind direction? (e.g., was it the upwind-most motor or the downwind-most motor?).

 

[cruisinforgold]

I have replicated this twice now with different props. Though it is windy outside and was just hovering in the same spot and orientation. Only had enough juice left in the lipo to check again really fast with different props. I am charging it back up now to try again. Will report back. I do know that these brushless motors are constantly changing speeds and adjusting to keep the craft levels. I have only had motors this hot on my race quads and have not experienced this on the Mavic until now. Or just have not noticed it until now.

Also, here's a link to a Phantom P3 that diagnosed a bad motor rising (or failing). Different bird but the process and using the data collection tools for the Mavic Pro can be utilized for the same purpose here - now I assume you only want to diagnose before doing a warranty return, anyway.

Read the OneNote postings #1 and #2.

Just checked my motors speed...

 

[fizzlefish]

The fact that it is windy is consistent with the hypothesis that one of the motors might have to be working much harder than the others in order to keep the aircraft stabilized. If you aren't able to immediately do a flight test under conditions of no or little wind, then I would try to make sure that the next time you fly that the Mavic is pointed in a different direction with respect to the wind (and stays pointed in the same direction with respect to the wind throughout its short up-and-down flight test).

BTW, did the hot motor of your previous flight test have any particular position with respect to the wind direction? (e.g., was it the upwind-most motor or the downwind-most motor?).

To be honest I didn't pay attention to that. I will this time around after I get it back in the air. This was kind of a "Ow, holy **** that is hot... Wtf. Maybe the props are not balanced?" moment after I landed due to battery voltage.

 

[LeMur]

Start the motors and check the temperature after several minutes without taking off.

 

[fizzlefish]

Update.

Started up the motors without liftoff and let them run for awhile. Again the back left motor is hot to the touch but not burning hot. The other 3 are warm. I decided to fly around for about 20 minutes. Landed and motor is burning hot to the touch with the other 3 cool. Going to hit up DJI and see what they say. Thanks.

 

[BD0G]

I believe that you can also pull your .dat file and examine current draw to that specific motor. It may be worth a try. Cant remember if datcon tracks this value.

The .DAT is on the Mavic Pro itself. To retrieve it use DJI Assistant 2 and go to the Flight Record tab. After confirming that it's OK to put the Mavic in Flight Data mode a list containing the recent flights will appear. Select just the Flight Control File of the incident flight and then press Save To Local. Ultimately a file with a name something like DJI_ASSISTANT_EXPORT_FILE[2016-10-27 22-40-28].DAT will be created. That file can't be attached here so you'll have to Dropbox it and post the link.

Then use BudWalkers's DATCON to examine the current draw to that specific motor. As one would expect it should be higher than all the other 3 motors.

 

[flyNfrank]

@BudWalker is the house guru on this type of issue. I guarantee you will get a more detailed response on the issue from him. You will need to upload the DAT file and provide a dropbox link. It is worth the time to start now on getting the DAT file uploaded at least to your pc.

 

[Wombat55]

Update.

Started up the motors without liftoff and let them run for awhile. Again the back left motor is hot to the touch but not burning hot. The other 3 are warm. I decided to fly around for about 20 minutes. Landed and motor is burning hot to the touch with the other 3 cool. Going to hit up DJI and see what they say. Thanks.

Too bad. Sounds like there really is a problem with that motor, perhaps a shorted winding. No easy fix. Going to have to have DJI look into repairs.

 

[BudWalker]

I believe that you can also pull your .dat file and examine current draw to that specific motor. It may be worth a try. Cant remember if datcon tracks this value.

The .DAT is on the Mavic Pro itself. To retrieve it use DJI Assistant 2 and go to the Flight Record tab. After confirming that it's OK to put the Mavic in Flight Data mode a list containing the recent flights will appear. Select just the Flight Control File of the incident flight and then press Save To Local. Ultimately a file with a name something like DJI_ASSISTANT_EXPORT_FILE[2016-10-27 22-40-28].DAT will be created. That file can't be attached here so you'll have to Dropbox it and post the link.

Then use BudWalkers's DATCON to examine the current draw to that specific motor. As one would expect it should be higher than all the other 3 motors.

Funny you should mention motor current. The next release of CsvView/DatCon has motorLoad which is probably what is needed. There are other motor data that may help here.
@fizzlefish I can point you to a pre-release beta that you could use. Or, you could retrieve the .DAT and post a Dropbox link like @BD0G suggests. Here is some more info on retrieving the .DAT

EDIT: But, looking at the .DAT won't affect the outcome in a material way. The Mavic still has to be repaired by replacing the motor and/or the main board.

 

[GerdS]

It's either a defective motor bearing (does it turn as easy as the other motors?) or it is a problem with the corresponding ESC which might drive the motor with a wrong timing.
I am not sure if ESC software will also get updated with firmware, but might be woth a last try. Within DJI Assistant reset your Mavic to factory defaults and the reinstall the firmware. If this doesn't solve the problem, there is nothing left you can do on your own. Call DJI for warranty repair then.