Mako79 said:Try and separate the wires like the attached to prevent shorting.
Shuether said:Mako79 said:Try and separate the wires like the attached to prevent shorting.
I'm not sure if this is mentioned in the later pages, I just started reading this thread and will read all the way through. According to that DJIforums link, the worst heat comes from the Mosfets so best to keep the wires away from them as well.
Pmcdn said:Shuether said:Mako79 said:Try and separate the wires like the attached to prevent shorting.
I'm not sure if this is mentioned in the later pages, I just started reading this thread and will read all the way through. According to that DJIforums link, the worst heat comes from the Mosfets so best to keep the wires away from them as well.
Looking at the board where the motor wires are attached, where are the mosfets (or what do they look like)?
Prylar Bek said:The sky is falling....the sky is falling...
I have made numerous measurements, current and temperature sensors on the drive wires, etc. over the past week, including replacing the MOSFETs and intentionally blowing them up to see what can cause a sudden MOSFET/ESC failure. Any sudden interruption of the motor rotation, like a tip-over or striking a small tree branch, will immediately blow the ESC. I'll be posting more details shortly, along with some O-scope waveforms.
Thanks for your comments and insights. I no longer believe the motor wire size is the main culprit. I thought they were about AWG22-24 wires coming from the motors. Turns out, they are the actual wires from the windings; two solid wires from each motor winding covered with colored shrink tubing. After 15-20 minute test runs at full throttle, they only climbed to about 40C - enough to make the shrink tubing "spoungy." However, the MOSFETs get very hot after a 15-20 minute hard run. The best safeguard is to ensure the motor drive wires are not touching each other and lifted above and away from the hot MOSFET chips.
Paul
flyNfrank said:Personally, I think the problem we are having with our quads dropping from the sky, is either current misfires through the wire insulation, or it's something before the motor/ESC combo. Most likely it's the 2nd one I mentioned, with being before the combo.
Not all, but when most drop, they drop by rolling to side. They roll, then drop. Because they seem to share this same characteristic is why I fill like it's in what communicates with the ESC's.
MapMaker53 said:Whether you apply additional insulation or not, it still leaves you with a relatively thin solid copper wire in a vibrating environment. It is bound to eventually fail while in the air. I think the time frame and failure rates probably has a direct correlation to total flight hours with the new motors -- which widely varies from owner to owner.
ELHEAPO said:suerly dji would have many experts working for them and do many hours of test flights wouldn't they have known this as a possible flaw it's not like this is a new company making an inexperienced oversight.
wow. Mine did the same thing, but I was high enough that I was able to recover.robinb said:
slothead said:Something just dawned on me.
I haven't read all the recent posts that are now on this thread (I don't have that much time), but In one of those sets of photos, I thought I saw a "V2" identification on the ESC. If we know for sure that the motors in that image are the newer V3 version (I can't remember the new number), and they are being driven with the old ESCs, what those images show is exactly what I would expect to happen: ESC overheats and MOSFETs short, allowing high current through the "new" wiring to the motors, and everything looks burned up.
The above may not be the case (I'm not sure what motors and what ESCs were in use there), but whatever the case, I would strongly recommend that you don't use new motors with old ESCs because it is very likely you will experience what those images show. (I think this caution was stated by DJI some time ago.)
If you are asking me Mori, I can't say, but it is important to know that the new motors are being used with new ESCs. My concern is configuration control. How do we identify the ESCs? I think new motors can be assured they are new by the thinner wiring, but I don't know how to differentiate the new from the old ESCs.Mori55 said:So how come some new v3 owners are having this problem ?
slothead said:Something just dawned on me.
I haven't read all the recent posts that are now on this thread (I don't have that much time), but In one of those sets of photos, I thought I saw a "V2" identification on the ESC. If we know for sure that the motors in that image are the newer V3 version (I can't remember the new number), and they are being driven with the old ESCs, what those images show is exactly what I would expect to happen: ESC overheats and MOSFETs short, allowing high current through the "new" wiring to the motors, and everything looks burned up.
The above may not be the case (I'm not sure what motors and what ESCs were in use there), but whatever the case, I would strongly recommend that you don't use new motors with old ESCs because it is very likely you will experience what those images show. (I think this caution was stated by DJI some time ago.)
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