One Moto/ESC acting strangely during output calibration?
« on: April 20, 2018, 08:17:24 am »
Hi everyone! :)

I think could need some good advice. Set up my quad, checked the PDB and the outputs. Went into the setup wizard and all went fine until I reached the outputs calibration. Motor Nr.1 just goes into some slow stop & go when I turn up the bar, while the other Motors wiggle kind of randomly (not all the time, just  unperiodicaly every now and  then). When i pull the bar a bit to far to the right the ESC beeps one time & the Motor stops. All other Motors are doing fine, spinn up properly and dont cause the wobble in the other Motors. This was under Oneshot configuration of the Esc (they are! Oneshots). Reconfigured the ESC zu regular rapid ESC, Same Problem as before, except the other Motors (2-4) dont jiggle. So reconfigured to OneShot, tried it again. Now I found a Point where the Motor Starts spinning stable. Its around the same starting point as the others, but it sounds way slower than the others, and still causes the jiggle in the others. Did anyone expirience something similar? What would you check first? I thought I ask you Guys before starting to disassamble it. Thank you for you help!
PS. : The ESCs are bound in 2 Circuits to the PDB so that I just used two hardpoints on the PDB. So if this would be a Power Problem at last the other Motor in the same circuit should have the same problem?
PPS.: Im using a revo clone.

Re: One Moto/ESC acting strangely during output calibration?
« Reply #1 on: April 21, 2018, 04:17:10 pm »
Jerky stop and go motor is NOT good.  It usually means that one of the 3 motor wires is not connected and that usually means that wire is burned out, inside the motor.  Do not use "full throttle" to make it try harder because that may force it to burn out for some versions of firmware.

Have you ever seen any smoke at all?  Or heard pop or hiss from it burning?  Or found that it smelled like it was burned?

Use an Ohm meter to look for "open circuit" in the 3 motor wires.  They should all look like they are shorted out to each other, direct connection from each wire to the others.  Test all possible combinations of wires (call them A B C) so test A-B, A-C, and B-C.

So if you test motor wires (A B C) and find:
A-B is zero Ohms (direct connection / shorted)
A-C is open (meter does not change when you connect this)
B-C is open (...)
then you have discovered that wire C is "open circuit" and the motor is bad.

I have fixed one such motor, but I must say that for most motors, it is more useful to work you normal job for money and buy a new motor than to spend an hour or more fixing (rewinding) it.  Just buying the correct magnet wire to rewind with will sometimes cost more than a new motor.

Re: One Moto/ESC acting strangely during output calibration?
« Reply #2 on: April 21, 2018, 05:35:46 pm »
Jerky stop and go motor is NOT good.  It usually means that one of the 3 motor wires is not connected and that usually means that wire is burned out, inside the motor.  Do not use "full throttle" to make it try harder because that may force it to burn out for some versions of firmware.

Have you ever seen any smoke at all?  Or heard pop or hiss from it burning?  Or found that it smelled like it was burned?

Use an Ohm meter to look for "open circuit" in the 3 motor wires.  They should all look like they are shorted out to each other, direct connection from each wire to the others.  Test all possible combinations of wires (call them A B C) so test A-B, A-C, and B-C.

So if you test motor wires (A B C) and find:
A-B is zero Ohms (direct connection / shorted)
A-C is open (meter does not change when you connect this)
B-C is open (...)
then you have discovered that wire C is "open circuit" and the motor is bad.

I have fixed one such motor, but I must say that for most motors, it is more useful to work you normal job for money and buy a new motor than to spend an hour or more fixing (rewinding) it.  Just buying the correct magnet wire to rewind with will sometimes cost more than a new motor.
Hi,
Thank you very much for your reply!
That does not sound too good :D.
I turned the rpm slowly up and that particular motor started to smell "hot" and it got also just a little hot, but no smoke or an electrical "sparkling" sound. The others Motors stayed cool. Thank you for this tip! I will try that.