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Torque limitations, cant reach max RPM?

Hi,

I've just successfully ID a 810KV hobby motor, that I intend to use for a quadrocopter. I am seeing some strange behavior that I dont know how to fix.

When I test the motor, I am able to speed it up to 11 000 RPM. But when I install the blade on the motor, the motor goes only to about 4000 RPM. The current is still below the limiting current, but I noticed that the torque is quite high around 10 000 Nm.

Is there a limit to the torque?

4532.user.hThe user.h is attached.

  • The prop provides a load, so it will always run slower than unloaded. And sometimes a prop you can fit on is too much load for the motor to run to max rating under load. 

    Try running without the speed controller using 05a and commanding max current Iq. This is only using pure Sinewave modulation so it won't hit full speed, but it will give you about 75%. See if this is an improvement. 

    If so, then try 10a with higher modulation if 1.33 and tune the speed controller for stability. (Kp will have to be 4-10x lower than default most likely). 

    Sorry, I'm on mobile and can't review the user.h

  • Chris,

    sorry for the late reply.

    Thank you I'll try that the first thing on monday!