Need to get rid of noise from DC motor. Help please.

Discussion in 'The Projects Forum' started by lidstrompl, Mar 16, 2012.

  1. lidstrompl

    Thread Starter New Member

    Mar 16, 2012
    Hi. I'm running a small projects which involves finding current change due to various dynamic loads imosed on a DC motor. I'm using arduino with motor shield and 10k pot to adjust direction and speed of the motor. My motor is a 12V 30:1 gear DC (EMG 30)
    I'm using Picoscope for my scope and PicoLog to lod my data. I get tremendously large noise when I measure my voltages across. I have installed an 0.1 uF capacitor across the motor terminals and two 0.047 uF caps - across each lead and the motor casing (shied) - but it didn't help.
    Also, when using picoscope, what is the right way to connect the red and black clips across the motor - I may be doing it wrong (it does not allow to connect the two across the resistor as it gives the grounding effect).
    Excuse me for my poor electrical knowledge, but I hope some more experineced folks here woud give me some tips on how I can get rid of this noise.

  2. jimkeith

    Well-Known Member

    Oct 26, 2011
    Tell us more about how you are powering this motor--certainly not a 10K potentiometer
    Sounds like the a PWM motor drive control
    What is the motor current rating and base speed?
    A simple low-pass filter for your voltage and/or current measurement may do.
  3. lidstrompl

    Thread Starter New Member

    Mar 16, 2012
    Thanks for your response jimkeith.
    I'm using a 12 V DC supply from my AC-DC adapter.
    Yes PWM is used to control the drive.
    Rated current 530 mA Rated speed 170 rpm
    The thing is, PicoScope 2203 does not allow for a low pass filter... :(
    Here is the motor data:

    Any more suggestions??