Proper wiring of line noise filter on washing machine

Discussion in 'General Electronics Chat' started by ajgarvin, Sep 10, 2015.

  1. ajgarvin

    Thread Starter New Member

    Sep 10, 2015
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    I posted more or less the following as a comment on a old thread, but probably should have just started a new thread, so here goes...

    I feel like a dope even though I don't think I've made a mistake. My brand new Samsung washer has the noise filter shown by the image following this paragraph. I needed to change the power cord (to one with a plug that lays flat against the wall) and was careful to pay attention to which terminals on the filter the line and neutral attached. But, now that I'm looking at the schematic diagram on the filter, it seems to disagree with what I'm 99% sure I observed.
    20150910_213505.jpg

    The input leads (from the power cord) attach to terminals 1 and 2, and the output leads attach to terminals 3 and 4. On the base of the physical filter, terminal 1 is diagonally opposite terminal 4 (and terminal 2 diagonally opposite terminal 3). This physical orientation matters because of what I believe I observed when I disconnected the input leads. But first let me state something I'm sure of: the black output lead is definitely attached to terminal 4 and white output lead to terminal 3... I'm sure of this because these never got disconnected. However, this seems to contradict the schematic, which indicates that the hot output should be on terminal 3 and the neutral output should be on terminal 4.

    When I disconnected the input leads, I was "sure" that the black input wire was diagonally opposite the black output wire. That would mean that the black input was on terminal 1 because it's the terminal diagonally opposite terminal 4, where the black output wire definitely is (and would mean the white input was on terminal 2). This input arrangement would be consistent with the schematic, but worries me because the output leads are connected in reverse (as described in the paragraph above). So now I'm doubting what I was previously sure of!

    What happens if I am wrong about what I thought I observed and end up getting the input leads reversed as a result? What's the best way to make sure I'm getting it right (do I have to go to an appliance store and, when nobody's looking, open the top of another Samsung?)?
     
  2. dl324

    Distinguished Member

    Mar 30, 2015
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    Use an ohmmeter to check for continuity between pins 1&3 and 2&4 instead of guessing. I don't know how appliance grounding is or isn't done in your country. If the appliance connects neutral to the chassis, reversing the lines could be fatal.
     
  3. ajgarvin

    Thread Starter New Member

    Sep 10, 2015
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    Thanks, Dennis. I'm in the US, by the way.
    So, I take it that continuity should be from line to line and neutral to neutral? That's simple, assuming that the black output lead on terminal 4 is not (perversely) the neutral, which I guess I can test by checking for continuity to the chassis.
     
  4. dl324

    Distinguished Member

    Mar 30, 2015
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    Yes, probably not zero ohms, but something small(ish). Since you're in the US, you should wire white to white and black to black. Earth ground should be connected to the chassis.
     
  5. ajgarvin

    Thread Starter New Member

    Sep 10, 2015
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    As I mentioned, the black load is wired to terminal 4 even though the schematic on the filter indicates it should be on terminal 3. I take it from what you've said that the inputs and outputs still should be wired black to black and white to white, but will having the line (hot) on the "wrong" side of the filter circuit diminish or change its effectiveness?

    I have the wiring diagram for the washer, by the way, and have attached it.
     
  6. dl324

    Distinguished Member

    Mar 30, 2015
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    Wiring black to black and white to white is what our electrical code says should be done. For cases where that isn't done, the wrong colored wire should have tape of the correct color so it's clear that something is not typical.

    That wiring diagram is confusing. The filter indicates terminals 1&2 are input, but the wiring diagram indicates they are output. There are references to "L" and "N" on the part and wiring diagram. L should always be black and N should be white. I don't know enough about the filter to say what would happen if it was wired wrong...

    I'd wire it the way you're 99% certain is correct and take a picture the next time you're disassembling something so you can be 100% certain.
     
  7. #12

    Expert

    Nov 30, 2010
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    Now that we have established the proper way to wire this, you don't need the answer to that question unless you are going to intentionally wire it wrong.
     
    Last edited: Sep 11, 2015
  8. ajgarvin

    Thread Starter New Member

    Sep 10, 2015
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    #12, I think you've misunderstood:
    As I said, I know with 100% certainty that the black output wire is on terminal #4. I know this because I haven't disconnected the output wires, but also because the output wires go to a connector that can only fit on one way. So, if I attach the input leads to have black to black -- which is what I presume you mean by "the proper way to wire this" -- I'll have to put the black input on terminal #2. That arrangement puts the hot wires on what the filter's schematic shows as the neutral side, which is why I asked the question you quoted.

    To put it another way, the only way to wire it completely right (black to black and in agreement with the filter's schematic) would force me to rewire the connector that goes on the output terminals. Unfortunately, the washer's wiring diagram doesn't help. dl324 calls that diagram confusing [with regard to the connection of the filter]. I'd call it ambiguous at best, which is not what one wants in a wiring diagram!
     
  9. #12

    Expert

    Nov 30, 2010
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    Apparently we have NOT established the proper way to wire this.

    According to the label in the photo:
    (1) is black from the power line.
    (2) is white from the power line.
    (3) is black to the washer.
    (4) is white to the washer.

    According to the wiring diagram:
    Line is white
    Neutral is black
    (Not the way we do this in the U.S.A.)

    and you, "know with 100% certainty that the black output wire is on terminal #4"

    So, what would happen if you wire the filter backwards?
    The power line would be connected to Bond through 1.09 megohms instead of 1.65 megohms.
    That would cause an extra current from Line to Bond of 37.2 microamps and an increased waste of power measured as 4.5 milliwatts.

    Other than that, nothing.
     
    Last edited: Sep 11, 2015
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  10. ajgarvin

    Thread Starter New Member

    Sep 10, 2015
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    #12:
    I trust that your conclusion as to what happens if the filter is wired "backwards" (hot on the side that's supposed to be neutral and vice versa) is correct but, for the record (and in case it triggers any further constructive comments), I can't agree confidently with part of what you say on the way to that conclusion.

    You say "According to the wiring diagram, Line is white [and] Neutral is black".
    I presume you infer this because on that diagram...
    • L (on the filter's power cord side) is across from WHT on the output side, and
    • N is across from BLK.
    If that's the justification, the inference may not be correct because the wiring diagram...
    1. doesn't show the physical arrangement of the filter's terminals;
    2. doesn't label all filter terminals with numbers;
    3. labels the output terminals with numbers that aren't consistent with my 100% certainty that output black is on #4 and output white is on #3; and
    4. doesn't show the internal circuitry of the filter (one wouldn't expect it to, but it would make things less ambiguous).
    Moreover, wiring the power cord so that Line is white and Neutral is black is against code and is definitely not the case here because the plug that attaches to power cord to supply is polarized and I have tested continuity from the wider blade (Neutral at the socket) to the white lead.
     
  11. #12

    Expert

    Nov 30, 2010
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    The noise filter is designed with bilateral symmetry and excellent insulation. It will filter noise by the same amount, and do it safely, no matter which way you connect it. The difference in your electric bill could be as much as one half of one cent per year. If you can afford that cash price, wire it which ever way seems right to you. Personally, I have spent more than one half of one cent worth of my time on this.
     
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  12. ajgarvin

    Thread Starter New Member

    Sep 10, 2015
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    #12: Thanks for your help (and thanks to dl324 as well)! You have certainly spent way more than $0.005 of your time on this (probably by several orders of magnitude), so don't feel obliged to read any further.

    For anyone who cares: I convinced the salesperson at a big box home improvement store to let me slide open the top of a Samsung washer like mine (luckily it only requires removing two screws). What I found confirmed what I was 99% sure of in the first place: the black wires are connected to diagonally opposite terminals (as are the white wires, obviously).

    I reconnected my power cord this way and the washer works fine. But my self-doubt (and #12's expenditure of time) would have been avoided if the color coding of the internal wiring of the washer had been consistent with the internal wiring of the line filter...
    • The black (hot) wire in the power cord is connected to terminal #1 of the line noise filter and the white (neutral) to terminal #2, which is consistent with the filter's schematic.
    • The load wires are connected black to terminal #4 and white to terminal #3.
    • Since continuity is from terminal #1 to #3 (black to white as wired) and from #2 to #4 (white to black), my conclusion is that Samsung has used a perversely inverted color coding for the load side of the filter (the washer's internal wiring).
     
  13. KeepItSimpleStupid

    Well-Known Member

    Mar 4, 2014
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    There is additional supression between the input terminal #1 and ground. Everything else is symetrical.

    Between #1 and ground, there should be line voltage.
     
  14. Johann

    Senior Member

    Nov 27, 2006
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    I followed this thread with interest and must say I agree with #12. It will function as a line filter either way. You could even swap input and output.
     
  15. KeepItSimpleStupid

    Well-Known Member

    Mar 4, 2014
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    For the most part yes. However, there is additional spike protection when it's installed CORRECTLY.
     
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