Inverter generates RF interference

Discussion in 'Electronic Repair' started by link, May 26, 2004.

  1. link

    link Guest

    I've got a grid tied solar array that generates a great deal of
    interference with AM radio signals. I can't pick up any AM stations
    inside the house when the inverter is running. At night when the
    inverter is shut down my stations come in fine.

    Any ideas on how to cut down this interference? I'm getting it on
    radios powered by the mains power and battery power so it's actual RF
    from the air but it doesn't seem to affect radios outside the house.
     
    link, May 26, 2004
    #1
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  2. link

    Pszemol Guest

    "link" <> wrote in message news:...
    > Any ideas on how to cut down this interference?


    Does your "inverter" create sine wave or square wave?
    If the second case, than this is the source of your problems.
    I do not know the easy way out other than replacing
    inverter for a sive wave electricity source...

    You can also go the other way: install AM antena
    and use it as a source for your radio receivers
    if they have the antena plug exposed...
     
    Pszemol, May 26, 2004
    #2
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  3. link

    link Guest

    On Tue, 25 May 2004 19:30:50 -0500, "Pszemol" <>
    wrote:

    >"link" <> wrote in message news:...
    >> Any ideas on how to cut down this interference?

    >
    >Does your "inverter" create sine wave or square wave?


    It's a grid tied Sine Wave Inverter. Specifically a Xantrex SunTie
    1500. It matches phase, frequency and voltage with the grid. This is
    what has me puzzled? In reality, I think the sine wave is made up of
    many discreet steps. The number "36" has been brought up before.
    Xantrex offered a free upgrade last year. This upgrade really boosted
    my energy production but at the same time it caused all this RF
    interference. I guess for the extra 30% power I'm producing now I can
    live with the RF, but I would like to be able to listen to the ball
    games.
     
    link, May 26, 2004
    #3
  4. link

    Ken Weitzel Guest

    link wrote:
    > On Tue, 25 May 2004 19:30:50 -0500, "Pszemol" <>
    > wrote:
    >
    >
    >>"link" <> wrote in message news:...
    >>
    >>>Any ideas on how to cut down this interference?

    >>
    >>Does your "inverter" create sine wave or square wave?

    >
    >
    > It's a grid tied Sine Wave Inverter. Specifically a Xantrex SunTie
    > 1500. It matches phase, frequency and voltage with the grid. This is
    > what has me puzzled? In reality, I think the sine wave is made up of
    > many discreet steps. The number "36" has been brought up before.
    > Xantrex offered a free upgrade last year. This upgrade really boosted
    > my energy production but at the same time it caused all this RF
    > interference. I guess for the extra 30% power I'm producing now I can
    > live with the RF, but I would like to be able to listen to the ball
    > games.



    Can't help but be curious about where in the world you are?

    The reason being, that if it is indeed RF, aren't
    your neighbors gonna be a little upset with you?

    Take care.

    Ken
     
    Ken Weitzel, May 26, 2004
    #4
  5. link

    Stan Guest

    link <> wrote:

    }I've got a grid tied solar array that generates a great deal of
    }interference with AM radio signals.
    Hmmm...the question becomes: is the interference being radiated to
    each radio? OR, is it being "impressed" onto the AC lines into your
    house? If that's the case, some low pass-filters will do the trick.

    Stan.
     
    Stan, May 26, 2004
    #5
  6. link

    w_tom Guest

    Maybe an inverter bought on price rather than based upon
    numerical and technical specs. Any decent inverter includes
    circuits to eliminate the RF noise. This being decades old
    technology. However too many consumers cannot be bothered
    with the science; which is why inferior inverters are sold.

    Your solution. Big bucks for filters that would have
    normally been part of the inverter for little additional
    cost. To the benefit of others - did it come with a long list
    of numerical specs? If not, then they are probably forgetting
    to provide 'standard' functions - such as filters. America
    needs more immigrants to explain these so basic technical
    concepts to us. This noise problem demonstrating a
    consequence when consumers don't first demand technical specs
    - only buy on price. It is not a personal attack. Such
    failures that were not acceptable 30 years ago are now more
    common as products are bought based only upon one
    specification- price. Its called a bean counter mentality.
    Specs (or missing specs) would have made the RF interference
    problem painfully obvious up front. No long 'page plus' list
    of numerical specs? Then expect the worst.

    link wrote:
    > It's a grid tied Sine Wave Inverter. Specifically a Xantrex SunTie
    > 1500. It matches phase, frequency and voltage with the grid. This is
    > what has me puzzled? In reality, I think the sine wave is made up of
    > many discreet steps. The number "36" has been brought up before.
    > Xantrex offered a free upgrade last year. This upgrade really boosted
    > my energy production but at the same time it caused all this RF
    > interference. I guess for the extra 30% power I'm producing now I can
    > live with the RF, but I would like to be able to listen to the ball
    > games.
     
    w_tom, May 26, 2004
    #6
  7. link

    Asimov Guest

    "link" bravely wrote to "All" (25 May 04 23:33:45)
    --- on the heady topic of "Inverter generates RF interference"

    li> From: link <>

    li> I've got a grid tied solar array that generates a great deal of
    li> interference with AM radio signals. I can't pick up any AM stations
    li> inside the house when the inverter is running. At night when the
    li> inverter is shut down my stations come in fine.

    li> Any ideas on how to cut down this interference? I'm getting it on
    li> radios powered by the mains power and battery power so it's actual RF
    li> from the air but it doesn't seem to affect radios outside the house.

    Some things to try:
    - wrap all the wires going to the inverter through a large ferrite toroid.
    - add series inductors & bypass the line with capacitors.
    - arrange the input/output wires at right angles to one another.
    - shield the inverter inside a grounded electrical box.

    .... She said it was either her or the Ham Radio... OVER...
     
    Asimov, May 26, 2004
    #7
  8. link

    link Guest

    On Tue, 25 May 2004 19:54:34 -0700,
    (Stan) wrote:

    >link <> wrote:
    >
    >Hmmm...the question becomes: is the interference being radiated to
    >each radio? OR, is it being "impressed" onto the AC lines into your
    >house? If that's the case, some low pass-filters will do the trick.
    >
    >Stan.


    It seems to be radiated to each radio rather than being impressed onto
    the AC lines. I'm getting the interference on battery powered radios
    as well as those powered by mains.
     
    link, May 26, 2004
    #8
  9. link

    link Guest

    On Tue, 25 May 2004 23:04:32 -0400, w_tom <> wrote:

    > Maybe an inverter bought on price rather than based upon
    >numerical and technical specs.


    >No long 'page plus' list
    >of numerical specs? Then expect the worst.


    It's a Xantrex Sun Tie XR 1500

    http://www.xantrex.com/products/product.asp?did=133

    The Inverter was purchased based on performance claims by the
    manufacture; Performance claims that were never achieved until they
    recalled and redesigned the units. This took about 3 years and some
    diligent work from some very dedicated "Customers". This inverter is
    supposed to be the top of the line model made here in the USA,
    designed to be intertied into our USA electrical grid. This is the
    third unit I've had. The first unit died an early death but it didn't
    generate RF interference. The second unit also generated no
    interference but also generated very little power. This third unit
    really performs very well as far as power generation is concerned but
    it also generates this RF interference.

    It came with a pretty long list of specifications. The data sheet is
    online and obtainable from the above link.

    The (thick) maunal goes on to chart Efficiency Curves and Temperature
    derating curves which I've verified with my own data collection system
    which is also online (sometimes) at
    http://www.daemonet.net/energy/index.php
     
    link, May 26, 2004
    #9
  10. link

    w_tom Guest

    The specs do provide cursory information. IOW only some
    important technical numbers are provided. Important is
    Harmonic distortion of less than 5%. It means that AM radio
    interference probably (only maybe) is not coming out of AC
    power output. But, for example, I see no reference to any FCC
    requirements. No reference to even claim it does not
    broadcast excessive RF radiation. IOW by interfering with the
    AM radio (which even computers are not permitted to do), it
    does exactly what specifications claim.

    Just like power supplies in computers and plug-in UPSes, the
    inverter uses a PWM to create AC voltage. That is typical
    source of RF interference. And just like those power supplies
    and UPSes, the inverter should create just as minimal
    interference.

    Increased interference could indicate a partial failure or
    weakness inside the inverter. Hard to say from so little
    information on their web site. However a quick examination of
    their box interior suggests nothing to eliminate RFI/EMI.

    You could take it one step farther - to determine where
    noise is being radiated from. From incoming DC voltage wire
    (acting as an antenna)? On outgoing AC wire? From directly
    inside box? Use the battery powered AM radio. And use radio
    on different stations - powerful and weak - to categorize the
    amount of interference energy being transmitted at different
    locations. That information might help to further eliminate
    the RFI/EMI problem - the reason for AM radio interference.

    But again, those specs don't even claim to meet FCC
    requirements. FCC Part 15 requires that the inverter not
    interfere with radio reception.

    link wrote:
    > It's a Xantrex Sun Tie XR 1500
    >
    > http://www.xantrex.com/products/product.asp?did=133
    >
    > The Inverter was purchased based on performance claims by the
    > manufacture; Performance claims that were never achieved until they
    > recalled and redesigned the units. This took about 3 years and some
    > diligent work from some very dedicated "Customers". This inverter is
    > supposed to be the top of the line model made here in the USA,
    > designed to be intertied into our USA electrical grid. This is the
    > third unit I've had. The first unit died an early death but it didn't
    > generate RF interference. The second unit also generated no
    > interference but also generated very little power. This third unit
    > really performs very well as far as power generation is concerned but
    > it also generates this RF interference.
    >
    > It came with a pretty long list of specifications. The data sheet is
    > online and obtainable from the above link.
    >
    > The (thick) maunal goes on to chart Efficiency Curves and Temperature
    > derating curves which I've verified with my own data collection
    > system which is also online (sometimes) at
    > http://www.daemonet.net/energy/index.php
     
    w_tom, May 26, 2004
    #10
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