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HELP: PT Accuator loud audio feedback?

Discussion in 'DIY Motion Simulator Building Q&A / FAQ' started by CScott, May 17, 2021.

  1. CScott

    CScott New Member Gold Contributor

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    Hi all, I get a pretty nasty audio feedback through my speakers. Almost sounds like a bad ground or something similar but I bought this setup prebuilt so I have not torn it apart yet. Thought I should ask around before start guessing.
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    Ads Master

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  3. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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  4. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

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    My Motion Simulator:
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    Bad ground and/or ground loops???

    Is ALL system connected to the same single outlet as it supposed to be (PC, speakers, peripherals and servomotors power in star connection to a common power strip etc)???
  5. CScott

    CScott New Member Gold Contributor

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    It is over 2 power strips in the same outlet. Not really sure on the ground vs ground loops. I spent some more time this weekend messing with it. 100% if the receiver is off their is no feedback so it is between the audio receiver and the PT Accuator.
  6. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

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    On in this case you need to add a line filter on the power lines that end up on the AASD-15A servos, to block EMI noise go back through the lines and reach your other equipment:

  7. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

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  8. CScott

    CScott New Member Gold Contributor

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    I had a chance to to watch this and do some testing. I was able to at least make sure the ground loop was not the issue (thank you, I looked it up). After watching the video on this inline filters I think I am going to order them. Look easy to install and designed to solve the exact issue. As always you all rock!
  9. CScott

    CScott New Member Gold Contributor

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    Going to try to install this tomorrow. I will let everyone know the results.
  10. CScott

    CScott New Member Gold Contributor

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    No go, when ever I add the ground it blows the gfci on the wall. With or without the EMI box. When I received this I did not have a ground to the wall. I watched the video and matched the wiring. No luck. Any thoughts? I still get the emi "whine" and the ground is causing an issue. I must be missing something.

    Attached Files:

  11. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

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    I don't think its good idea plugging device with load like the servo drive on GFCI wall outlet. They are particularly picky when it comes to power they deliver and sometimes may hide nasty surprises like my old house that had no ground wire at all and they installed GFCI to get around it regarding regulations...

    IMG_20210602_075419.jpg

    IMG_20210602_075429.jpg

    Can you open the wall outlet and check if there is ground wire installed indeed?
  12. CScott

    CScott New Member Gold Contributor

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    Yeah, the wall outlet is actually less than a year old and I know it is grounded. Plus, it blows 3 different GFCI's (tested 20 AMP's with extension cord to the bathroom etc.) I can toss into a standard grounded plug and see if throws the main breaker for the room. Sucks, I have watched Berry's wiring video showing the ground being used and another video which I thought was from PT showing no ground from the wall. Certainly grateful for your help! I inspected for crossed wires but no luck..
  13. Petertje

    Petertje “Engineering changes the world.” —Isaac Asimov

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    What I did to mitigate the inrush current is place an NTC inline. This has a higher resistance when cold reducing peak, and lowers resistance when getting hot. It will reach a balance and it remains warm/hot but that is normal and not a problem if you choose the correct power. I choose a 20Ohm- 10A version which works well for my 6DOF with 6x AASD-15A.

    For the EMI noise in the audio: when I have a AASD-15A drive with lots of unshielded cable I can even wrap them around the audio cables no problem. Imo it would be good to know if the problem originates in the PC, or the external audio system. If you disconnect the external speaker/system and record audio from the source on your pc and play it back on another device you know has no problems, you know a bit more.