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Re: [taigtools] Re:How to stop losing steps with stepper motors

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  • Ken Cline
    ... Do you mean 2.5 kohm? If your resistance is really 2.5 ohms, you are operating on three orders of magnitude too little current, and torque is proportional
    Message 1 of 54 , Oct 2, 2009
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      On 2 Oct 2009, at 7:14 PM, Douglas Vogt wrote:

      > So it's much worse at cutting brass but still can't cut air.
      > Resistors measure 2.5 ohms.


      Do you mean 2.5 kohm? If your resistance is really 2.5 ohms, you are
      operating on three orders of magnitude too little current, and torque
      is proportional to current.



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    • Ken Cline
      ... Again, just what will this test? Not current draw from the power supply, since that is already low assuming the motors are moved slowly. If the Gecko is
      Message 54 of 54 , Oct 4, 2009
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        On 4 Oct 2009, at 10:56 AM, Jack wrote:

        > Reducing the value of the current setting resistors temporarily as
        > already mentioned, say to 2K or so, should be sufficient as a test
        > unless the supply is actually defective.

        Again, just what will this test? Not current draw from the power
        supply, since that is already low assuming the motors are moved
        slowly. If the Gecko is suspect, I'd just switch channels and see if
        the same axes fail.

        > Personally, I wouldn't run any type of supply in this service
        > without a large storage/filter cap at the output.

        Good point! Gecko recommends 2,000 - 10,000 uF across the output of a
        regulated or switching supply [http://www.geckodrive.com/upload/Step_motor_basics.pdf
        ]. That could be the problem. Make sure the supply will start
        properly with that sort of capacitive load.

        > Is anyone else here using 20' cables without problems? That seems
        > excessive to me.

        The signals driving our steppers barely extend above audio
        frequencies. I don't see a problem with 100' cables, as long as
        resistance is kept reasonably low.



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