MR60

Why logs show throttle cuts & current drops to zero when did not happen ?

Posted by Hugues on March 2, 2014 at 7:49am

Hi,

I flew a quad today having two issues; and not sure they are linked.

Quad is configured : pixhawk 3.1.2, 880KV 3DR motors, 11x4.7 props, 4S battery, Power module.

Problem 1: motors 1 and 2 get extremely hot after a few minutes (not touchable) while motors 3 & 4 are just warm. Why is that ?

Problem 2: logs show strange short drops in throttle and current to zero, while I did not notice that in flight! Why would that be ?

3691101742?profile=originalHere is my log file if someone could help me solve these two mysteries ?

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Replies

  • Eric March 2, 2014 at 9:49am
    It could be that one of your motor mounts is clocked at a slight angle about the tube. For example, if your motor #4 were at a slight angle to the right (looking from the end of the tube into the frame), that motor would be adding CCW torque about your CG. Motors 1 and 2 would then have to spin faster to stabilize yaw.
  • Developer
    Bill Bonney March 2, 2014 at 8:52am

    I would look at your Transmitter, or connection to CH3 on the Pixhawk, as the throttle channel on input is going up and down. and the output to the motors is going up and down in sync. You can see the battery voltage recover, each time the throttle decreases.

    Not sure why you are getting hot motors though.

    3701673707?profile=original

    • MR60
      Hugues > Bill Bonney March 2, 2014 at 9:05am

      This is strange because I use the SBUS, so all channels pass through one wire. Is there an issue with the X8R receiver and pixhawk ?

  • MR60
    Hugues March 2, 2014 at 7:49am

    here is the log

    2014-03-02 15-52-45.zip

    https://storage.ning.com/topology/rest/1.0/file/get/3701673776?profile=original
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