[JCALF]

Hi everybody,
I'm hoping someone can tell me what's going on. I'm currently working on my first quad build. I've wired up the quad and I'm at the vehicle setup wizard step. I get to the step where you plug in the battery for the first time to calibrate the ESC's. For some reason, when I plug the battery, the fourth motor(looking down at the quad, it would be the rear-left one) keeps burning up. I burned the first one, then ordered a replacement and that one burned up too. All other motors are fine and I'm able to calibrate them. I've checked the voltages on the power distribution board and the voltage coming out of the ESC that corresponds to that particular motor and they seem fine. not sure what's going on. Any advice would be greatly appreciated.

Right after I typed this, I went back to my quad and decided to do a little more troubleshooting. Turns out I was wrong about the ESC. I unplugged the burned motor and one of the good motors from their respective ESC's, then I plugged the battery into the power distribution board and measured the voltage coming out of each ESC. Turns out that the functioning ESC outputted 0 volts, while the faulty ESC outputted 8.3 volts, which is the source voltage. Looks like the faulty ESC is just outputting whatever the input voltage is and is not regulating it at the output. Has this happened to anyone else, and is my analysis correct?
Thanks

[Mateusz]

It's more common to have faulty ESC than motor I think. If motor gets burned I would probably check ESC first before anything else.
I wouldn't try to fix ESC, just replace it with new one and then connect new motor. But never happened to me, I would probably lose motor as you did.
I suggest making a short movie, uploading to vimeo to show input and output voltage with multimeter and burned motor, post it on sellers website and ask for refund, if you are still within usual 30days period you might get full refund or replacement (depending on sellers and their rules).

[JCALF]

Cool! Thanks for the advice. The movie idea sounds good. I just ordered a new ESC and  another motor from readytoflyquads.com. Do you know anything about the quality or performance of their parts? These are the parts I'm getting:

http://www.readytoflyquads.com/brushless-outrunner-hacker-style-20-28m
http://www.readytoflyquads.com/f-20a-fire-red-normal-esc-with-rapidesc-fw-for-multirotor

I'd like to know what you think about these.
Thanks

[Mateusz]

I never got disappointed by t-motors, they're expensive but have good bearings and could survive a lot.
When it comes to ESCs, hardware has changed quite a bit.
My first ESCs were also Atmel based Afro 30A (like yours), but these are quite old by now. Later SiLab chips came like FVT Littebee it was a bit step up as they were smaller and lighter.
Then some STM32 ESCs appeared but are expensive to produce and not very popular although offer nice features. Then appeared some ESCs with BusyBee2 (BB2) chip which have dedicated hardware PWM (don't do PWM bit-banging) and can run motor way smoother and quite. These ESCs run newest BLHeli_S firmware. BLHeli_S also supports OneShot or DShot protocol. For new quad I would recommend ESC with BLHeli_S. (The _S is distinguishes it from older just BLHeli firmware).

I dont want to advertise Banggood here or RaceStar brand as RaceStar is a Chinese company that steals open-hardwar designs, removes credits and sells things as "own" design, I know I shouldn't buy from them, but they were cheap So these are the BLHeli_S ones I use now (just 4in1 variant) http://www.banggood.com/Racerstar-RS20A-20A-BLHELI_S-OPTO-2-4S-ESC-Support-Oneshot42-Multishot-for-FPV-Racing-p-1063904.html