Motor Test Failure

Course Questions Drone Building
1

When I try the motor test through mission planner, only two of the motors are spinning. All four motors are twitching when the drone is on, so I know they are all receiving power. I also tried re-calibrating the ESCs and double checking the ESC wiring. What other steps should I take to fix this issue?

1 Like
2

On the 2 motors that aren’t working, in the motor test bump up the % throttle a bit, maybe even to as much as 10%. Be careful if indoors.

Normally, the ESC calibration sets the lowest PWM the motors will start spinning at. If bumping the throttle up a bit in motor test gets the motors to start spinning that weren’t before, this probably points to a bad ESC calibration.

Are you doing the MissionPlanner based ESC calibration, or the RC controller based RC calibration (as seen in this video) https://www.youtube.com/watch?v=q80QijmQzOI

3

Thank you. Bumping up the % throttle to 10% got all four motors spinning.

I used the RC controller based calibration. If the fact that I ran into this problem indicates bad calibration, do you have any steps to fix this? I have already tried recalibrating multiple times and that didn’t seem to change anything.

4

Since bumping the throttle worked, you’re correct that this points to the ESCs not having the same idea of where “minimum” throttle is. If recalibrating with your RC transmitter hasn’t fixed it, here are a few additional steps you can try:

  1. Try Mission Planner’s “All at Once” Calibration
  • Instead of the RC-based method, connect via USB and use Mission Planner’s ESC calibration function.
  • Go to Setup → ESC Calibration and follow the on-screen steps.
  • This tends to be more consistent because Mission Planner sends the same PWM range to all ESCs simultaneously.
  1. Verify Radio Endpoints
  • Make sure your radio calibration in Mission Planner shows 1000–2000 µs (or close) for throttle.
  • If the throttle minimum is higher (e.g. 1100), the ESCs may not arm properly.
  • Sometimes repeating radio calibration first, then ESC calibration, clears mismatched endpoints.
  1. Increase “MOT_SPIN_ARM” Slightly
  • In Full Parameter List, search for MOT_SPIN_ARM (or MOT_SPIN_MIN).
  • This sets the PWM percentage at which motors start spinning.
  • If the ESCs are calibrated slightly differently, some won’t start until a higher value.
  • Bump it up in small increments (e.g., from 0.10 → 0.12 → 0.15) until all motors reliably spin at arming.