RLProto
lvl.2
Flight distance : 4026 ft
Brazil
Offline
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A customer which has a M210 RTK reported a strange crash and send the drone to maintenance. He said that he heared a strange sound and the drone fell down, braking many parts.
Ok, I got the equipment and the first thing the came to my attention was a burned motor (LFRONT motor). I have seen many kinds of crashs and fly aways, but I have never seen a burned motor in the matrice series.
So my question was: did it burn during flight or something else went wrong and it got stucked on the ground? I don't see any of them happening, but...
I opened the motor/ESC and I found that the red wire was also burned and it was loose on the ESC side (picture 1 and 2 attached). So, if it happened during flight, of course that the drone would fell down.
Analyzing the flight log, I confirmed that the M210 lost the LFRONT motor during flight.
Log: https://drive.google.com/open?id=1jhU9LTlkzD-Fu_xxVuSl0skVmz2hV6Vz
A strange behaviour came to my attention: LFRONT motor current started to oscilate few minutes before the crash (picture 3). According to the log, LFRONT motor current was around 50A and oscillating. The other motors were fine.
I couldn't find any log event reporting a motor/ESC issue before it touched the ground.
So I ask your help. What could cause this current oscillation? Did it burn in the air? Why? Have you seen something like that? Did I miss anything important in the flight log?
Thank you.
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