Hello all,
my PixHawk Quadcopter copter was doing fine the day before yesterday but when I was trying to arm it yesterday it gave me a long beep and couldn’t arm it. I left the copter on the lawn and booted up my laptop on the terrace because I wanted to connect to the UAV with the 3DR radio in order to check with MissionPlanner what the reason was.
While my notebook was still booting, I heard a sizzling sound from the lawn and noticed that the UAV was on fire! Grey smoke emerged from the end of one arm where the ESC was located. I immediately ran to the UAV and disconnected the battery, the fire was still burning.
After a while the fire stopped and I took a look at the ESC. Only black crisps were left.
My question is:
What could have caused that fire? The fire started maybe 3 minutes after trying to arm it.
The copter was not armed and the transmitter was untouched, so my understanding is that no current was flowing at the motor side. A closer look at the ESC revealed that the fire must have started from the motor side of the ESC because the cables at the battery/pixhawk side are still intact.
The grass on the lawn might still have been wet when I placed my copter there so could water have caused a short-circuit at the A B C connectors between ESC and motor? I have little knowledge about electronics but I assumed that if no voltage on the motor side is applied, nothing can happen even if A B or C connectors are connected.
Is it likely that it was a short-circuit? Could a defect motor cause this kind of disaster?
Background Info: I used Tiger Motor S25A ESC and Tiger Motor U8-16 100kv motors.
Is it save to replace the ESC and try again or do I risk to burn more than the replaced ESC again?