Replace Berd-Air motor with brushless

  • Hi,

    I have ordered a pump from China that looks exactly like the Berd-Air type.
    I would like to change the DC brushed motor (in due course) with a 3 phase brushless motor.
    I have an ESC that needs a servo input signal, 1-2 mS pulses at approx 50Hz to control rpm.

    Before I go trawling through all the documentation,
    Will it be possible to write a start up script (to arm the ESC, as per RC norm) and can I configure a Duet3D output as servo output, with GCode speed control for variable cooling ?


  • administrators

    Yes, see the wiki page about controlling servos.

  • @jujudelta When you power up an ESC it won't start running the motor as a safety feature (you don't want a spinning blade to chop you up when you connect a battery) . One of these is almost the same thing as the driver in PWM fan- except it can handle a much larger motor. It has PWM input so you can connect it to the Duet board just like any normal PWM fan without having to modify any code to get around ESC type safety features.

  • How do you arm the ESC? If it is just a sequence of different pulse widths, it should be possible to do it from the Duet...

  • @dc42 said in Replace Berd-Air motor with brushless:


    i found article difficult for me. is there a connection diagram for duet+esc+brushless

  • @fma It depends on the brand and setup of the ESC, many require a PWM calibration- usually off, full speed and off, once saved it should know the min and max signals and arm when powered on with low/no PWM signal.

    Some require a sequence of powered low/no PWM, full on till it chimes, then low again every time it boots to arm, these are usually crappy ESC's.

    Bus type often need a flight controller to operate and should be avoided for this use.

  • Ok, thanks!

  • I used a pump like the one you described, and it died after maybe 100 hours. The plastic melted from friction where the excentric shaft moves the pump plate.
    The motor is noisy, but the pump by itself is as well.
    I'm not buying another...

    I want to 3D print a 'CPAP like' blower, powered by a brushless R/C motor, just like you described. Will see, but i'm confident it should work.

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