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Boe Bot Servos

TitoTito Posts: 4
edited 2009-03-21 12:54 in Robotics
Which is the maximum RPM that the servos on a Boe Bot can gives and under what circustances? (6V vs 9V)

I am trying to see what is the maximum radius I can machine for this servos.

Thanks.

Comments

  • AveryAvery Posts: 9
    edited 2009-03-18 12:15
    I measured one of my servos at:

    5v full speed 50 RPM

    9v full speed 69 RPM
  • UghaUgha Posts: 543
    edited 2009-03-19 12:08
    You don't want to apply 9volts to a servo...ever... the max you want to apply is I THINK 7.5volts. I'm pretty sure its somewhere around there anyways.

    If you have a 9volt supply on a BOE, make sure you run the servos off the 5volt VDD supply by switching the jumper as needed.
  • JDJD Posts: 570
    edited 2009-03-20 16:15
    Tito & Avery,

    That is correct,·9·volts is too much for·the·servos to handle.·Per the·datasheet and manual,·the max is 6.0 VDC, but I have seen 7.5 on the Servo Controller with no issues;·anything more you are running the risk of damaging the servos. Here is a link to the manual that will help explain some details about working with the Parallax Servos.

    Parallax Servo:
    http://www.parallax.com/Portals/0/Downloads/docs/prod/motors/crservo.pdf

    Hope this helps,

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Respectfully,


    Joshua Donelson
    www.parallax.com

    Post Edited (Joshua Donelson (Parallax)) : 3/20/2009 4:25:10 PM GMT
  • AveryAvery Posts: 9
    edited 2009-03-20 21:43
    Is that true for standard servos, too? The Parallax catalog lists 5 to 9 volts for the standard (which is the one that stuck in my head) and 5 to 7.5 volts for the continuous rotation.

    Is there a reason for the difference?

    Thanks for the info, though Ugha and Joshua.
  • JDJD Posts: 570
    edited 2009-03-20 23:58
    Avery,

    I'm not sure why the catalog as 9 VDC as the max; but the continuous and standard would be rated the same. The servos are both from Futaba-RC, but they are made for Parallax. Predominately the voltage in RC circuits·are roughly 7.5 VDC; but we recommend when using without exceeding 6 VDC to extend life on the servo.

    You can run a servo at a higher voltage, but it would be too hard to determine how long it will last. For example, I ran a servo, just as a test, up to 18 VDC before it died; quickly at that. So you could run them at a higher voltage, but keep in mind that it will decrease the life expectancy of the servo greatly; which is why we state 6 VDC in the manual and datasheets.

    I will let our marketing department know about the voltage statement within the catalog; excellent catch and question.



    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Respectfully,


    Joshua Donelson
    www.parallax.com
  • UghaUgha Posts: 543
    edited 2009-03-21 12:54
    The other day I was reading a page that compared the lifetimes of a hobby motor (the kind that comes with the Tamiya kits) at various voltage levels...
    At 1volt higher than the recommended 3volts, it cut the lifetime almost exactly in half!

    It got worse from there of course, but that'll tell you how bad overvolting motors are... and after all, a servo is just a DC motor with some controller
    electronics.
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