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speed control with a dc brushless motor — Parallax Forums

speed control with a dc brushless motor

zachlzachl Posts: 5
edited 2007-10-28 21:24 in BASIC Stamp
I have a eflite park 180 brushless outrunner motor with speed control that I want to use with the paralax homework board. can someone help me with the set-up of the board to get this type of motor to work.

If I use the example in the book for a servo set-up it does not work at all.

Thanks

Comments

  • quickster47quickster47 Posts: 35
    edited 2007-10-27 18:21
    What ESC are you using for your brushless motor? The ESC should interface with your board just like a conventional servo control because you are still supplying a PWM signal.

    Carl
  • zachlzachl Posts: 5
    edited 2007-10-28 01:15
    I do not have an ESC.· I thought I could control it with the board like a servo.· If you have any recommendations please let me know.

    Thanks
  • Mike GreenMike Green Posts: 23,101
    edited 2007-10-28 01:28
    You can't control a DC motor directly with a microprocessor. At a minimum, you need a driver transistor to handle the current load required. Typically these motors (especially if you want to reverse them) require an H-bridge driver like the L293 (www.me.umn.edu/courses/me2011/robot/technotes/L293/L293.html).
  • zachlzachl Posts: 5
    edited 2007-10-28 12:58
    Thanks,

    I am new to this. I assumed that because of the 3 leads and the speed control that it would work like a servo and thus follow the servo example in the parallax manuals.

    I have worked with both the sn75441 and l293. I will try with the schematics that I have on these chips.

    Thanks for your help on this.
  • Mike GreenMike Green Posts: 23,101
    edited 2007-10-28 17:40
    Do take a close look at the datasheet on your motor. You mention that it has speed control. That could mean anything. It might mean that the voltage on the 3rd wire sets the motor speed. It might mean that the motor expects some kind of serial data. Who knows? Don't just hook up something to it until you know what it requires ... you might damage it.
  • LilDiLilDi Posts: 229
    edited 2007-10-28 18:18
    http://www.e-fliterc.com/ProdInfo/Files/EFLPark180Instructions.pdf
  • zachlzachl Posts: 5
    edited 2007-10-28 21:24
    I took a step back. I setup the sn754410 chip and just set it up to run with a 2-lead dc motor. After a few wiring issues i am able to control the speed of a dc motor!!!!! [noparse]:)[/noparse]

    I am now back to the eflite motor. red and black wires i understand. it is the white wire that I beleive is the root of my problem.
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