motor overheat error messages

[randyvanscoy]

how do you tell which motor is over heating from the screen error says motor overheated, reducing speed to safe return... i have felt all motors when returned from 6-10 minute flights. all seem to feel same temp. i have brand new props on all motors, all free spin same with no power. hovers great, flys great, but after a while in the air, i get overheat warnings on dji pro screen. if i push it more, i get a battery overheat alarm also. if i just hover with it, they will not overheat. any ideas?? i have heard that if a prop is off balance, or motor off balance, this will cause it also. i dont know how to tell which motor is alarming. any ideas????

 

[Duchunter]

Grab each motor with your thumb and index finger and try to wiggle each one and see if there is any horizontal movement that would indicate a bad bearing. In a hover you may not be getting and metal on metal contact been it when your flying you may be getting a little contact between the magnets and the stator. I would check that first and if the bearings are OK I would ohm out each motor and make sure impedance is within spec. I just bought a new motor for my p4. One of the cw motors has a lot of movement so it's on its way out for sure. I wouldn't fly until you figure it out. It could fall out of the sky at any moment or worse, it could catch fire and go down in a blazing glory.

 

[royster]

Can you be a little more specific re- Testing motor with a meter? Assume you have to get to 2 wires running to motor? set to meter to read Ohm;s, look for what kind of range reading to be normal?

 

[HWCM]

Can you be a little more specific re- Testing motor with a meter? Assume you have to get to 2 wires running to motor? set to meter to read Ohm;s, look for what kind of range reading to be normal?

These are brushless motors. Brushless motors are AC not DC. These brushless motors are three phase motors, or perhaps a synchronous three phase motor with a variable speed electronic drive, the ESC units we are familiar with. In fact, with a four channel Oscilloscope, and three resistors (star) wired in to provide a neutral connection for the scope, you can look at a three phase voltage waveshape signal from any of these brushless motors.

 

[HWCM]

"Dry Testing" brushless motors (Update Sept 10 2008) - WattFlyer RC Electric Flight Forums - Discuss radio control eflight

 

[randyvanscoy]

ok thanks. i will look at them with scope. i am new to the drone thing and have crashed a few.....learning every day more stuff about them....3rd drone now..... the motors seem to be tight in both directions as far as movement. i also get a battery warning that says battery discharge currant high and battery gets really y hot. only happens on a long flight.

 

[Hamltnblue]

High Battery Discharge current can be caused by the overheating motor.

 

[quaddamage]

If you cannot decide which motor is the cause, look into flight logs to get specifics.

 

[aburkefl]

If you cannot decide which motor is the cause, look into flight logs to get specifics.

I thought that too, but, when looking at the raw detail from a flightlog (in my case, the flightlog created by Litchi), there is almost nothing to help out with motors. Certainly not a category specifically showing motor temperature. The only variable I can find is "IsMotorsOn" which obviously only tells you if the phantom is running at that point.

There are some specs available about current and batteries (voltages, temperatures and a few others). But something like motor temp (heaven forbid seeing something about ESCs!) appears to be unavailable. I also looked at some other data, hoping that maybe there would be something that would have a "relationship" to motor temp. I was unsuccessful. Perhaps someone else with a far better knowledge of the individual parameters could help.

Again, that's using flightlogs (that's the actual folder name from my iPad app) created by Litchi.

Art - N4PJ
Leesburg, FL

 

[quaddamage]

I didn't mean Litchi or other app logs, just full flight logs from the internal SD card. Enter flight logs mode to get access to them.

This page also suggests you can see the logs in real-time from your PC by connecting it to USB:
Firmware m0306 · mefistotelis/phantom-firmware-tools Wiki · GitHub

 

[PhantomFun]

I just had this exact issue w/ my P3 Advanced 2 days ago.

I flew out against the wind at ~11 MPH trying to get close to the Golden Gate Bridge and on the way back at 24 MPH, I received the error message about the motor. At one point the P3 stopped and hovered (I had initiated return home) once I realized this I had to override the idle to get her back before running out of power.

As she got closer I also received the over heating battery warning. At one point the P3 began emergency landing (was close to home but not quite). I was unable to cancel out of the forced landing and had to again override the landing to bring her down closer to home. I recall we used to be able to cancel out of emergency landing, in fact there's a red X that leads one to believe they can. In any case, none of the motors felt hot, yet the battery was hot to the touch. Haven't flown since to see if it was an isolated incident.

Perplexing!

Mark

 

[With The Birds]

These are brushless motors. Brushless motors are AC not DC. These brushless motors are three phase motors, or perhaps a synchronous three phase motor with a variable speed electronic drive, the ESC units we are familiar with. In fact, with a four channel Oscilloscope, and three resistors (star) wired in to provide a neutral connection for the scope, you can look at a three phase voltage waveshape signal from any of these brushless motors.

The waveform doesn't look too shabby even with the motor running, DJI is using basically the factory application note impememtatiin of Texas Instruments three phase gate driver SOC and power mosfets.

This looks remarkably different to the crudely chopped DC drive from a typical ESC, the DJI motors seem identical to a typical brushless DC motor (which as you likely know are a DC motor by definition. The point of difference is likely only the variable frequency sine wave drive.

 

[nightspy]

I just test the speed of the prop before take off they must be all in the same range or more than likely have a bad bearing

 

[With The Birds]

I just test the speed of the prop before take off they must be all in the same range or more than likely have a bad bearing

I'm not sure this observation is a reliable means of determining bearing condition. It is not uncommon to measure speed differences prior to launch. There would need to be a significant motor issue to provide for the ESC not being able to maintain the flight controller commanded RPM. Measuring motor temperature would be a much preferred and reliable means of ascertaining likely bearing condition.

 

[PhantomFun]

I've read another post (see link below) where others have experienced the same motor overheating message/issue. Seemingly, it is due to the latest firmware update having this feature. Some saying they experience the message multiple times while flying hard.

Motor overload

Mark

 

[PhantomFun]

Hi all, test flight last night on the recharged battery that got overheated from my previous flight. No issues with flight. I did receive the motor overloaded warning several times. It actually came and went a few times, even started to come up then went away before it was completely legible.

I was pushing hard to see if it would come up. I didn't experience any flight issues and did not get the battery overheating message. Once I landed the battery was pretty warm. I did run the battery down to critically low, to see if I could override the forced landing. I was able to override the forced landing by maintaining throttle up.

I wish DJI would give us the ability to cancel out of the force landing like we once had. The red X comes up, yet it is not functional (see picture). I much rather crash land on land, than softly land on water.

At this point, I am feeling like the motor overloaded message is an unintended consequence of the latest firmware being too sensitive.

I'd love to hear others input...

Thanks,
Mark