One motor still spinning at min throttle

[zestart]

hi Everyone,

I built a chinese quadcopter, calibrated the ESCs, ACC and MAG, but one of the motors is still spinning at min throttle.

It';s not a faulty ESC because when I plugged the motor in into D3, D11 or D10 instead of D9 it worked fine.

I have a feeling that it wants to level itself out, that';s why it';s still spinning. When I move the copter it spins faster or slower. Has anyone experienced anything like this before?

This is how it behaves:
https://www.youtube.com/watch?v=n3Fa_IDzCeo

Many thanks.

[FlyingMouse]

Have you tried lowering your end point on the throttle in the Tx?

[zestart]

I';ve just tried. didn';t help :/

[xxpitt]

calibrate escs?

[xxpitt]

or lower min command on flight controller?

[zestart]

I think this misbehaving is position dependent..
have a look at this video. it';s 1 minute long only. I';ve just recorded it.

https://www.youtube.com/watch?v=-qs500XgW_g

[Revs]

What flight controller and firmware are you using?

[zestart]

it';s a MultiWii flight controller.. MultiWii_2_2_SE_2_0
when I connect to it on bluetooth it';s recognised as Cirus BT

[xxpitt]

have you got it to spin motors when armed? disable it if you have see if it still happens

[Revs]

Ah, I';m not familiar with the MultiWii stuff. Sounds like it';s a firmware setting issue.

Crius BT is the bluetooth module. What firmware/software is the flight controller running on?

[zestart]

 #define MOTOR_STOP is enabled. So it shouldn';t spin at all when the motors are armed.

the FC software is arduino.

[Revs]

Ah right, never used it. Is there a setting like ';minimum throttle command'; or somewhere you can set the throttle PWM range being sent to the ESCs? They all sound to be starting and spinning up at the same time so I wouldn';t say it';s a calibration issue.

[xxpitt]

can you lower your min command?

[zestart]

I wish I could the bloody win10 doesn';t like the FTDI adapter, so cant recognise the flight controller on COM 5.

I';m on it....

On another note, I don';t understand why the other 3 motors work perfectly fine??

[Revs]

What ESCs are they?

[zestart]

all four are the same: emax simonk 12a

[Revs]

I thought they might be EMAX, they';re known for having slightly different startup points even when calibrated properly.

I suspect that your min throttle command is set really close to your motor start PWM. You really need to get that adapter working so you can check the settings on the FC. Prolly a driver issue as my FTDI adapter is fine on W10.

[zestart]

guys, although I';m still doing the testing, but so far it seems that the problem has been resolved.
Revs was right, the min throttle cmd was set to 1000, thats the same as the moto start.
I flashed a new thingy with 900 min cmd, and it seems ok...

Thanks to everyone who contributed...

(i had to reinstall win7 as I wasnt happy with w10... w7 recognised the new hardware and ftdi without any probs:D)

cheers guys.

[xxpitt]

or lower min command on flight controller?

can you lower your min command?

i think you';ll find i was said about min command earlier on 

[xxpitt]

though i would have min command at  1000 and your min throttle at 1040 or something, thats just me though

[zestart]

though i would have min command at  1000 and your min throttle at 1040 or something, thats just me though

xxpitt.. why? could you please share your experience?

many thanks in advance.

[fundiphil]

Seem to have the same problem - that is "One motor still spinning at min throttle"
I';m using Naze32 rev 5 with EMAX 12A BLHeli ESC';s. (sorry if I should have tarted a fresh thread rather than hijacking this )

I have tried the same thing - dropping min command to 900 on the fc but it hasn';t helped.
I suspect that while the symptom looks the same cause may be different.

Tried swapping 2 servo leads over on the Naze and the fault stayed with the ESC-motor pair.
I don';t understand why it should spin up with the other motors using the motor testing tab in baseflight, but spins up on its own as soon as the quad is armed normally.

I have just downloaded BLhelisuite but not sorted out means of connection just yet.