Looking for advice with motor issue

[arquit3d]

Hi guys,
I've just finished building my first quadcopter.
Most of the parts are from eBay (China) but there are some pieces from Hobbyking and local stores.
I'm running CC3D and I've succesfully configures it with OpenPilot (at least I think so).
After configuring it and cheking sensors and motors, I realized that I motor was experiencing some kind of problem.
It spins freely by hand, but when powered, it starts as an intermitent spining as power is increased, and just after a huge increase, it starts to spin as expected, even so with a different sound as the remaining motors do.
I've uploaded a youtube video in order to better explain the problem. The selected values in the motors 2, 3 and 4 is just 1 unit beyond its spin value, to have an idea of the increase needed to obtain the "free spin".
I could bet for a bad motor, but my soldering skills are not so good, so it could be another option, or maybe the ESC.
The problem is less obvious when there is no propeller in the motor, so I just realized of it when putting it.

Thanks in advance for any advice.

 

[katheiser]

This might help... I'm at work with no sound on your video so if you are explaining something I apologize. Also, If I'm way off base with this video I apologize...

 

[katheiser]

did you use bullet connectors from your motor to your esc or direct solder them? I am new to soldering as well and I had some motor issues too. I found my shoddy soldering, once fixed properly, did help some so be sure to check that.

 

[arquit3d]

Hi katheiser,
Thanks for the link. I checked it previously and my motor is not stiff when not connected, it rotates almost the same that the other ones (maybe just a little bit stiffer, but not as the video).
For the connection between ESC and motors, I solder them directly, without connectors, so I'll check the connections, just in case I missed something.

Thanks again.

 

[katheiser]

No problem. Im the kind of guy who would rather buy a new motor after checking the basics. So let me know what you did when your problem is fixed. Id be very interested...

 

[Jackson]

Well I guess you first need to run through all your plug in connections.

From the Wiki:

... In case CC3D is powered through the servo connectors, then only connect the power from one ESC and remove the positive and negative wire from the other ESC's. Connecting multiple voltage regulators (built in to the ESC's) in parallel could cause problems. Connecting multiple black ground wires could cause ground loops which we want to avoid.

This is most important if you are using fancy ESCs that output 5V via a switching regulator (SBEC), it's not as crucial if your BEC are of the linear type

May as well run through the setup again, being especial careful when you calibrate the ESCs.

Another take by Painless..

If that doesn't do it swap out the motor and see what happens.

 

[arquit3d]

Hi Jackson, thanks for the links. I'm suscribed to Painless360 channel and I checked the video some time ago, but it's nice to check it again now I'm "on-board". About the calibration steps, I checked the video and did in the same way, so I'll discard a configuration problem.

I also checked the solder joints and could be one of them not so well, so I resolder all the wires and it seems that motor behaviour has improved. Nevertheless, I want to test the quad outside to check the in-flight behaviour.

Thanks for your suggestions.

 

[Jackson]

Well good luck. But 'behaviour has improved' is not enough.

If it ain't right and doesn't match up with the others, your FCB will be constantly struggling and trying to compensate.

 

[arquit3d]

I prefer to check it outside before draw any conclusion. I'm going to be out for a few days, so I'll check when I come back. Thanks anyways for the advice.