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current draw vs. actual RPM for DC motors — Parallax Forums

current draw vs. actual RPM for DC motors

MatthewMatthew Posts: 200
edited 2005-02-25 17:23 in General Discussion
Hello,

Does anyone know how current draw relates to actual RPM of DC motors, if the load is a constant?

Thanks,
Matthew

Comments

  • StarManStarMan Posts: 306
    edited 2005-02-25 04:11
    I'm not a motor expert but i would bet it depends on the motor....· And, I'm sure it depends on the load.· There are probably a family of curves for differents loads.
  • Robert SchwartzRobert Schwartz Posts: 141
    edited 2005-02-25 04:25
    I believe that StarMan is right. A low-quality cheap pager motor will draw a lot of current, while high quality Maxon motors draw very little. The load also affects current draw. The greater the load, the more current a motor will draw. To find out the exact specs on the motor you are using, check the manufacturer's datasheet.
  • Paul BakerPaul Baker Posts: 6,351
    edited 2005-02-25 08:23
    The stall current is the highest draw, no load is the lowest draw. I do not know if the draw is linear to the load, but it can be roughly determined using different loads and a DMM
  • bobledouxbobledoux Posts: 187
    edited 2005-02-25 15:57
    look at "gearmotors compared" under Solarbotics.org
  • nick bernardnick bernard Posts: 329
    edited 2005-02-25 17:23
    in dc motors current draw is linearly proportional to torque, not speed. hence has the load goes up so does the current. the motor's speed/torque curve indicates how fast the motor spins as the load uncreases.

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