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DC Motor and noise ...

Discussion in 'Robotics & Mechatronics' started by voidptr, Nov 5, 2012.

  1. voidptr

    voidptr Member

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    I will run 2 small dc motors on a little bot im building ...
    i already used standard caps noise reduction , 1 cap (0.1uF) across motor terminals and 2 others from the terminals to the motor casing ...

    noise level is not bad but i still can see a bit of it.


    is grounding the casing of motor to a common ground with the power battery be a good think / good practice ?, fast silly tests don't seem to show any difference ( im running 2 different sets of batteries for motor and controller ...

    im thinkink to have shielded cable to motor this might be where noise spread...

    any others good practice, advise ?

    :)
     
  2. misterT

    misterT Well-Known Member Most Helpful Member

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    - Twist the motor leads together.
    - Install a toroidal ferrite core on the (twisted) motor leads (near the motor).
    - Use shielded cable and ground the shield from both ends.
     
    Last edited: Nov 5, 2012
  3. voidptr

    voidptr Member

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    :)
    I saw those kind of cables with core before, but never really thought about them, after few researches and thoughts it makes good sense :)

    I think i have 2 or 3 already made from recycle old junk already :)
     
  4. dave

    Dave New Member

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  5. RichTheDude

    RichTheDude Active Member

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    Note the shield should never carry current...
     
  6. Mike odom

    Mike odom Active Member

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    Just seeing the noise isn't a problem... there's only a problem if it interfers with your control circuitry. I did an industrial timer that turned on/off several AC solenoids and had a 1/4hp motor connected to the same power supply that came into my board. I used filters on my power supply to the micro and could put the unshielded board right up against the motor with flawless operation. Here's what I used:

    View attachment 68583 View attachment 68584
     

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