LibrePilot Forum
Users => Vehicles - MultiRotors => Topic started by: trikkky on May 13, 2017, 11:17:05 pm
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First drone build. DJI F450 look alike.
All solder joints are working.
No shorts anywhere.
No exposed wires.
No Screw touching the motor windings (triple checked)
Running Libre on CC3.
A2212 1000Kv motors
30A simonK ESC's
E-Flite 3S 1500 20C battery (using one from my fixed wing build, waiting on a higher capacity battery)
So I've burnt 2 ESC's due to random reasons.
First time: First flight, 5 mins in, 4th ESC (SW) started smoking randomly, I was only at about 30% thrust. the quad was probably 10ft in the air.
Second time: Replaced all 4 ESC's with the red SimonK 30A ones. I started the calibration process for the 2nd ESC (NE) and moved the slider to find the natural frequency and it caught on fire.
After each small flight, i stop it to do a temp test on all ESC's and the 4th one is usually the warmest.(ive heard thats common with using the CC3D as it draws its power from the 4th ESC)
I'm on my LAST spare ESC and I'm afraid to run the drone because ill have to wait another 2-3 weeks for spares to come in.
Any suggestions or ideas?
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Well the one thing I can think of is that you have a motor that has a bad winding (open or short). You need to find it to stop burning ESCs. Maybe you know which motor was connected to the ESC that burned up. Try setting it aside and testing the others.
Open motor legs (ESC disconnected) are easy to check for. When measuring a good motor, a normal ohm meter should show a dead short from each leg to each other leg (AB, AC, BC) because the resistance is less than 1 ohm.
Shorted legs are harder to check for. You need an ohm meter that goes down to 1/10th ohm or even less. I have checked resistance by using an automotive bulb (1156 or 2156) and a 3 cell lipo and an amp meter all in series with a pair of motor legs to run about 2 amps through the pair of legs. With that connected, measure the voltage across the motor legs. Resistance = Voltage / Current. Measure all three leg combinations for the motor (AB, AC, BC) and they should all be about the same and probably 0.1 to 0.3 ohms.