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DC Motor "Pout" meaning — Parallax Forums

DC Motor "Pout" meaning

xanaduxanadu Posts: 3,347
edited 2013-11-16 12:21 in Robotics
Having trouble finding out what "Pout" on the graph on this datasheet means (PDF) - http://www.lynxmotion.com/images/data/pghm01.pdf

Comments

  • xanaduxanadu Posts: 3,347
    edited 2013-11-15 20:27
    Yes, thank you. Reminds me of a parasitic and induced total drag curve. So the power out in this case is kg-cm?
  • SRLMSRLM Posts: 5,045
    edited 2013-11-15 21:53
    Nope, that's the x axis. It looks like they're using torque to "tie" all the different functions together onto a single graph. Power is measured in watts.

    There's a good answer here:
    http://electronics.stackexchange.com/questions/27931/torque-kgcm-what-is-kgcm

    What's interesting with this datasheet is that point #4 says "Rated Load ... 1.12Kg-cm", but the graph goes from 0 to 9 Kgcm. It seems that they measured (calculated?) the full graph, but you can only operate to between the 1st and 2nd vertical bars (< 1.8Kgcm).

    At least that's what I think it is saying.

    Hmmm. On further inspection, the table on the left has 11 rows, which matches the 11 columns in the graph. But, the values are all sorted from highest to lowest. This clearly does not correspond to the graph. Did somebody use Excel sort before posting it into the table? But then what about the units on the x axis? I'd probably take the graph as a rough non-numerical estimate, and base any decisions on the specifications and the first link I posted in #2.
  • xanaduxanadu Posts: 3,347
    edited 2013-11-16 08:16
    Oh okay watts, right. I wasn't sure if that meant electrical power or some kind of torque.

    The rated load much be in some kind of unit per volt or something? If the stall Kg-cm is higher than the "do not exceed 1.12Kg-cm" it really doesn't add up.

    On further inspection I am equally confused about the chart as well.Usually datasheets have me stumped on a few things until after I hook it up so I have decided to just see what other people are using and go from there.

    SRLM are you the roboticist is San Diego Sportbike meetup?
  • ercoerco Posts: 20,256
    edited 2013-11-16 12:02
    Peak power on a brushed DC motor is tricky to measure directly, but typically occurs at half the no-load RPM and half the stall torque. Both of those values are easy to measure.
  • kwinnkwinn Posts: 8,697
    edited 2013-11-16 12:21
    The graph is rpm vs torque so yes, it is power out.
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