After researching the topic for a long time, I decided to build my first FPV drone.
Anyways, I was bench testing this drone a few times before the fireworks, testing receivers, motors etc, but in the last test, I armed the quad and the motors spun. Quickly after that, I saw smoke and heard some popping. Looking closer, one of the motor's wires popped off. Could this cause ESC failure? The ESC is completely gone. Would this cause any damage to components such as the VTX, camera etc as well as the motors? And if so can these be tested?
I would guess this could cause the ESC to fry, they are pretty sensitive to spikes in systems and if the free wire shorted things between the outputs or otherwise caused some other part of the ESC to short then the ESC is likely fried. One thing might not be aware of if new too is the CF frames are conductive so you need to add some 3M or similar mounting tape or electrical tape on the arms or otherwise between a ESC/ESCs and the frame itself.
ESCs can fry out if a motor gets stalled and the ESC is pumping "too much" current out and without the blades spinning has no cooling so can effectively cook itself, in your case sounds like a short since the sparks and smoke and all.
In the good news category very likely the rest of your gear is fine. In general I'd just replace the ESC and then see if any other components acting strange, when an ESC goes down there is a small chance it shorted a lot of current through the coils in the motor wires (allowed power to flow unregulated from battery) which can toast the motor windings too (enamel coating on them can deal with a lot of heat but a lipo can pump out a lot of current so it'll cook it if hooked up directly).
Again generally speaking I've had a lot of ESCs burn out on me and not take down other components, there's always a chance something caused a big voltage spike to kick back through things but typically voltage regulators on board can absorb some amount of that so long as it is a relatively "instantaneous" event. Having a low ESR capacitor on the power input coming into your VTX can help with absorbing ripples/spikes in the voltage to help clean up the signal, but I would assume cam vtx etc are all fine until see evidence of failure on those components.
Also if you are suspect of if some motors or part of a ESC or individual ESC fried out can swap motors, if the problem moves with the motor it's a motor problem, if the problem doesn't move with the motor it's probably an ESC or signal from FC to ESC problem.
Would bench test where run each motor individually either from betaflight or from blheli suite (props off). Basically if everything responding as expected when using sliders in the motors tab of betaflight or bl-helisuite then can know the signal from FC to ESCs is working fine and see if anything glitchy or rough when spinning the motors would check signal connections and gnd connections between FC and ESC.
Never had one just throttle up on me really have had them flip because of bad FC orientation or props on wrong motor etc (but wouldn't take off in those cases more than a ft off the gnd before flipping). I think runaways in general either from throttle from FC to ESC being interpreted incorrectly (can try calibrate ESCs or use different protocol for FC to ESC signal connection in betaflight configuration), or can be from PID values being way off and the quad "over correcting", if P is too high compared to D value then can overshoot a lot, if D value too high can burn out motors or ESC because is doing fast corrections based on last moments that could cause big voltage/current spikes that can fry things.
If suspicious this is an issue I would reflash the FC to make sure version on FC matches with version of betaflight configurator you have, would get the latest available right now too, sometimes changes in the FC setup require new configurator controls to properly adjust specifically around how PID values are set/used.
Yah if you arm the quad and it has stabilizing mode on then the motors will sort of drift around in speed on the bench but if use motors tab to control them individually then they should basically ignore the stabilization and pid loop is just sending throttle signals more directly. Same with bl heli suite is just connecting more directly to the escs in that case and just using the FC as a bridge for that communication.
Hi again, so i looked more into the FC I read somewhere that if you type `version. into the CLI this will provide the correct target for flashing the FC. Just wanted to make sure that this was correct.
I found this on a web also for my FC
The target is different to that specified in betaflight.
Forgot to mention, I bench test the motors separately and they are responding ok I think as in the correspond when varying speed.
Ah yah that should be all good actually it's a bit confusing because the stm32 chips get used in lots of different flight controllers (f3, f5 or more recently the f7 chips). The main chip on the flight controller board is probably that chip but there is board config that tells betaflight which pins on the chip are hooked up to what pads on the board for connecting inputs or output signals.... Technical weeds aside everything looks okay there versions wise to me, BF 4.3 is pretty recent and so long as configurator isn't complaining it needs an update you should be all good there. A couple things to check at this point would be either "soft mounting" the flight controller on gummies or looking into the notch filters to remove noise from motors generally I've had more success removing twitches in yaw and other motion problems with "better" soft mounting. Another thing to check out might be the betaflight black box log, you can download the file from FC flash if it has it and use separate black box log viewer app to play it back and see if the gyro or accelerometer values are jumping unexpectedly (again maybe notch filters can help remove the jostle or soft mounting). Some vid of it doing the thing with our without black box logs might help someone else see the issue if they've experienced it and chime in.
Hi. Thanks for replying to these messages. your a real help!
So unfortunately I didn't have the monitor hooked up when testing (which I realise was a mistake) and I also don't want to do it again being to new to the hobby but I managed to find this in one of the logs.
All the logs are looking the same as the one above.
One thing i didnt mention was that this is a custom build with a light aluminium base plate. I have mounted the FC and ESC onto a TPU gasket i suppose you could call and i have used the gummies for spacing. Imagine below
Could the mounting/damping of the stack be the issue in this case?
Ah dang well the soft mounting should actually help, I wonder if betaflight filters are preconfigured for the frame resonance of CF with soft mounted FC like you have but the aluminium frame is causing some issues? Basically the tpu or soft mounting ideally physically filters out the small fast vibrations from the motors some so the gyro is "seeing" only the overall motion of the quad rather than all the "noise" from shaky frame/motors. I wouldn't imagine the frame is to blame too much since have printed my own 5" quad before and it flew okay considering I didn't know how to fly it yet .
If you haven't flown before might want to pick up a tiny hawk or similar small prebuilt as well since they are more durable and can be a lot of fun (just get a lot of batteries).
Also simulators like lift off or velocidrone can be good to get feel for how much you need to tweak around with the throttle (probably more than you'd think since need to adjust thrust as you're adjusting the pitch or roll angle to keep close to constant up force). Glad to offer info where I can unfortunately just don't have direct answer on this one since haven't experienced it myself and can probably happen from a few different things. Sliding down the p and d terms in betaflight config might help it react a little less aggressively to input/errors from the target angle.
ok, thanks again. Ill probably repost onto a different forum if I don't get a response.
I have lift off and it's great. I have some drone experience but not this sort of drone experience If that makes sense? I haven't built any and thought well why not just build a custom one for I have resources. If I just get over this last hurdle I think I might have got it finished.