Hi guys,
3DR arducopter, APM2.5 :
during ESC calibration i noticed one of the fourth ESC (motor4) an extreme overheating. Three possibilities : ESC problem, motor problem or PDB problem on output motor 4.
I excluded ESC and motor problem by swapping the "hot" ESC by a nother ESC : this other ESC was also getting hot. Then I used PDB output n°3 on motor 4 and everyhting was fine -> this excluldes a short on motor n°4.
So obviously I have a problem with my PDB on output 4, that provokes extreme overheating of the ESC. I measured with an ohmeter the resistor between the + and - of PDB output 4. It is the same as all other outputs (so no short at that level). Plus the fact that even if the ESC overheats, the motor 4 still turns fine !
So what could be a cause on that PDB that makes the output 4 , thus the ESC4 overheat, but still driving the motor to turn fine ??? A short on the PDB ? Did I solder something wrong on the PDB ?
Please help because I have exhausted all I could test. Should I disassemble the whole thing to get a closer look at the PDB ? What other tests could I do on the PDB to detect an eventual issue ?
I want to avoid having to replace a PDB, not only is it more dollars to dish out, but further it is a pain to assemble and solder.
Thx,
Hugues
Replies
we've been building our SteadiDrones now for a while, over a year and we've always simply connected ALL ESC 3pin (red, ground and signal) wire plugs directly to the APM, with jumper on to power RX via the input rail and NEVER had any problems with this. We use this on al our Quads, H6X and large EI8HT copters that have flown thouands of flights with no problems, I'm not sure how others are doing it, but this works very well for us.
Hi.
I'm using an external BEC (non-lineal) with my octo. I think it is a must.
http://www.hobbyking.com/hobbyking/store/__767__766__UBEC_Regulator...
It sounds like the BEC is overloaded. Using multiple (linear) BEC in parallel or using a larger BEC should solve the issue.
I disassembled the 3DR quadcopter to unmount the PDB. I then checked every single solder, they were fine. I checked if there were shorts but all was ok. I checked to be sure no bare cables or connectors were touching conductive parts of the PDB or connectors, all was ok.
I did the test described in my last post, the ESC number 4 was still overheating.
I then noticed that the 3DR PDB board has a specificity for its output number 4: this is also the output of the PDB where a black & red 5V servo cable is soldered to feed the APM output rail.
I then disconnected this cable from the APM and BINGO, problem is solved !
Conclusion and summary: for all of you out there who use a 3DR power board and 3DR power module, you must DISCONNECT the red&black servo cable between the PDB and the APM2.5 output rail.
If a moderator of the arducopter wiki manual reads this,could you please add this instruction to the 3DR assembly guide ?
thx,
Hugues
However i want to pinpoint the root cause(s) of this PDB output 4 causing ESC overheat.
I will disassemble the quad to recheck evey solder, to recheck there are no shorts. I will also try this test: i will power ESC 4 by PDB output 4, but using the signal wire of PDB output 3. This test will tell me if the problem is on the power/Dean circuit side or rather on the motor signal drive circuit.
Will keep you posted
Are you providing power to your APM 2.5 board from your ESCs? Do you have the power lead from all 4 ESCs attached to the APM 2.5 board? This is the configuration I'm using and I am having the same issue. I am starting to believe this configuration is causing this. Hopefully someone here can recommend a better way.