interference from large power supply?

Discussion in 'The Projects Forum' started by minkey01, May 14, 2016.

  1. minkey01

    Thread Starter Member

    Jul 23, 2014
    171
    0
    Hi, everyone! Hope you are enjoying your spring.

    I have a general question about a project I'm working on. The project is using this large power supply that has a very large capacitor and very large transformer. See attached doc. They are pretty big. My concern is about electrical interference that this might generate in the surrounding space. For example should I be concerned how close my circuits are mounted to this power supply. My housing is pretty tight and some of my circuit boards are coming close to the power supply. How close do you think I can come without trouble?

    Thanks!
     
  2. #12

    Expert

    Nov 30, 2010
    16,261
    6,770
    Based on the input impedance of your circuit, the length of the exposed wires, whether it is an amplifier or not, what frequencies it will work with, and the fact that you told us none of this, the answer is: "Nobody can know." I can't just imagine a magic box that might do anything at all, or nothing at all, or anything in between, and tell you how sensitive it is to the radiated fields of a power supply.
     
  3. Papabravo

    Expert

    Feb 24, 2006
    10,137
    1,786
    From the datsheet I can see that the power supply has the UL/CE mark. UL (Underwiter's Laboratories) is primarily concerned with electrical and fire safety. The CE mark is more stringent in terms of conducted radiation and EMC compatibility. You can always ask the manufacturer for more information and test data. From what I can see you are probably worried about nothing.
     
  4. AnalogKid

    Distinguished Member

    Aug 1, 2013
    4,523
    1,247
    This looks like a souped-up linear supply, which means that the vast majority of the radiated fields will be at 60 Hz and 120 Hz (US). Depending on the (secret) application circuits, this might be no problem, or a project killer.

    ak
     
  5. crutschow

    Expert

    Mar 14, 2008
    13,000
    3,229
    What do the circuits do?
     
  6. minkey01

    Thread Starter Member

    Jul 23, 2014
    171
    0
    Sorry for the lack of info in the original post.

    The circuits I'm worried about are audio circuits, specifically tape player audio circuits. Does that help with answering this interference question? Can anyone give a general distance to stay away from some of those psu components?

    Here is what the company said :

    "From an electrical noise perspective, the power supply meets the CE/UL certification requirements for noise emission and susceptibility. As far as the noise immunity abilities of your other circuit boards, I have no idea. You can mount the power supply close to Teknic components but third party components may have their own guidelines.


    Since the power supply produces heat, it should be mounted at the top of the enclosure. If it was mounted below the circuit boards, it would act more like a heater as the heat rises."


    I do have it mounted at the top just by dumb luck. lol. So the heat should be no problem. It is even right by a vent at the top.
     
  7. minkey01

    Thread Starter Member

    Jul 23, 2014
    171
    0
    this housing originally contained some very large motors that would turn the reel-to-reels and capstan shaft. i imagine those have some large windings in them that may have given off EM interfering fields, so maybe that helps with thinking about the feasibility of adding this new psu into the housing. the circuits were fine with those original motors in there and that was back in the 70s.
     
  8. Papabravo

    Expert

    Feb 24, 2006
    10,137
    1,786
    I don't think you have anything to worry about unless you can provide additional information. We had large power supplies adjacent to high voltage display drivers and digital cassette tape recorders without undue difficulty. It is true that it's not the same as audio circuits, but with careful layout, grounding, and shielding you should be fine.
     
  9. minkey01

    Thread Starter Member

    Jul 23, 2014
    171
    0
    Cool! I agree. Sounds like I should be ok. The audio wires are shielded well and the tape head sits on the opposite side of 1/4" metal wall. I will proceed with project and deal with unlikely issues later if they happen.

    Thanks again!
     
Loading...