Computer room static blowing server power supplies

Discussion in 'Electronic Basics' started by T, Apr 4, 2006.

  1. T

    T Guest

    A raised floor server room with 6 servers, fiber optic patch panels, large
    control system cabinets and large UPS system, has been recently been plagued
    by computer power supply failures. The supplies fail when apparently many
    tens of thousands of volts jump from inside the PS around the switching
    regulators to the chassis of the supply taking out all the components. This
    has happened to 8 supplies so far. A visible blue flash has been witnessed
    several times by pewrsons in the room.

    The servers so far affected are all sitting on the raised computer center
    floor. What ususally happens seems to be when a person enters the 12x20ft
    room or gets near a server a large snap is heard and the server is on the
    backup redundant PS, if it has not already failed.

    We have been adding grounding bonding from all computer case to the bldg
    steel, raised floor structure, etc to try to stop this. Its still happening.
    The computers are various brands and varoious ages, from 1 week old to 5
    years old. The probelm began occuring 2 months ago. The data center was
    built 12 years ago.

    We are at a loss to figure out how the charge is building up on the inside
    of the power supplies. I am thinking about the common power source, via the
    power cords Hot, Neutral and Ground conductor.

    The green wire should be bonded to the PC case. Apparently the PS regulator
    board floats above chassis potential. Apparently a large potential differnce
    is building. It jumps a 1 inch gap to the chassis. Burn marks from repeated
    arc overs are evindent (the arc that makes it fail is not the 1st time it
    occurs!)

    The Hot and Nuetral..how could a charge be coming in on these conductors and
    getting past the MOVs to build a potential on the boards.


    Any ideas would be appreciated.
    TJS
     
    T, Apr 4, 2006
    #1
    1. Advertising

  2. T

    GregS Guest

    In article <>, "T" <> wrote:
    >A raised floor server room with 6 servers, fiber optic patch panels, large
    >control system cabinets and large UPS system, has been recently been plagued
    >by computer power supply failures. The supplies fail when apparently many
    >tens of thousands of volts jump from inside the PS around the switching
    >regulators to the chassis of the supply taking out all the components. This
    >has happened to 8 supplies so far. A visible blue flash has been witnessed
    >several times by pewrsons in the room.
    >
    >The servers so far affected are all sitting on the raised computer center
    >floor. What ususally happens seems to be when a person enters the 12x20ft
    >room or gets near a server a large snap is heard and the server is on the
    >backup redundant PS, if it has not already failed.
    >
    >We have been adding grounding bonding from all computer case to the bldg
    >steel, raised floor structure, etc to try to stop this. Its still happening.
    >The computers are various brands and varoious ages, from 1 week old to 5
    >years old. The probelm began occuring 2 months ago. The data center was
    >built 12 years ago.
    >
    >We are at a loss to figure out how the charge is building up on the inside
    >of the power supplies. I am thinking about the common power source, via the
    >power cords Hot, Neutral and Ground conductor.
    >
    >The green wire should be bonded to the PC case. Apparently the PS regulator
    >board floats above chassis potential. Apparently a large potential differnce
    >is building. It jumps a 1 inch gap to the chassis. Burn marks from repeated
    >arc overs are evindent (the arc that makes it fail is not the 1st time it
    >occurs!)
    >
    >The Hot and Nuetral..how could a charge be coming in on these conductors and
    >getting past the MOVs to build a potential on the boards.


    It sounds like your UPS's should take care of everything.
    I woulds have the UPS's checked out. I would have building electricians
    check things out. I would have installed whole circuit transient protection
    at the breaker box feeding the room.

    greg
     
    GregS, Apr 4, 2006
    #2
    1. Advertising

  3. T

    Ban Guest

    T wrote:
    > A raised floor server room with 6 servers, fiber optic patch panels,
    > large control system cabinets and large UPS system, has been recently
    > been plagued by computer power supply failures. The supplies fail
    > when apparently many tens of thousands of volts jump from inside the
    > PS around the switching regulators to the chassis of the supply
    > taking out all the components. This has happened to 8 supplies so
    > far. A visible blue flash has been witnessed several times by
    > pewrsons in the room.
    > The servers so far affected are all sitting on the raised computer
    > center floor. What ususally happens seems to be when a person enters
    > the 12x20ft room or gets near a server a large snap is heard and the
    > server is on the backup redundant PS, if it has not already failed.
    >
    > We have been adding grounding bonding from all computer case to the
    > bldg steel, raised floor structure, etc to try to stop this. Its
    > still happening. The computers are various brands and varoious ages,
    > from 1 week old to 5 years old. The probelm began occuring 2 months
    > ago. The data center was built 12 years ago.
    >
    > We are at a loss to figure out how the charge is building up on the
    > inside of the power supplies. I am thinking about the common power
    > source, via the power cords Hot, Neutral and Ground conductor.
    >
    > The green wire should be bonded to the PC case. Apparently the PS
    > regulator board floats above chassis potential. Apparently a large
    > potential differnce is building. It jumps a 1 inch gap to the
    > chassis. Burn marks from repeated arc overs are evindent (the arc
    > that makes it fail is not the 1st time it occurs!)
    >
    > The Hot and Nuetral..how could a charge be coming in on these
    > conductors and getting past the MOVs to build a potential on the
    > boards.
    >
    > Any ideas would be appreciated.
    > TJS


    Put a humidifier inside the room, the air is too dry and static electricity
    builds up.
    --
    ciao Ban
    Apricale, Italy
     
    Ban, Apr 4, 2006
    #3
  4. T

    T Guest

    This was th 1st thing we fixed. The RH was 15%, we raised it to 45% (its
    winter). The adjacent control rrom is around 15% .
    TJS

    "Ban" <> wrote in message
    news:ayBYf.15381$...
    >T wrote:
    >> A raised floor server room with 6 servers, fiber optic patch panels,
    >> large control system cabinets and large UPS system, has been recently
    >> been plagued by computer power supply failures. The supplies fail
    >> when apparently many tens of thousands of volts jump from inside the
    >> PS around the switching regulators to the chassis of the supply
    >> taking out all the components. This has happened to 8 supplies so
    >> far. A visible blue flash has been witnessed several times by
    >> pewrsons in the room.
    >> The servers so far affected are all sitting on the raised computer
    >> center floor. What ususally happens seems to be when a person enters
    >> the 12x20ft room or gets near a server a large snap is heard and the
    >> server is on the backup redundant PS, if it has not already failed.
    >>
    >> We have been adding grounding bonding from all computer case to the
    >> bldg steel, raised floor structure, etc to try to stop this. Its
    >> still happening. The computers are various brands and varoious ages,
    >> from 1 week old to 5 years old. The probelm began occuring 2 months
    >> ago. The data center was built 12 years ago.
    >>
    >> We are at a loss to figure out how the charge is building up on the
    >> inside of the power supplies. I am thinking about the common power
    >> source, via the power cords Hot, Neutral and Ground conductor.
    >>
    >> The green wire should be bonded to the PC case. Apparently the PS
    >> regulator board floats above chassis potential. Apparently a large
    >> potential differnce is building. It jumps a 1 inch gap to the
    >> chassis. Burn marks from repeated arc overs are evindent (the arc
    >> that makes it fail is not the 1st time it occurs!)
    >>
    >> The Hot and Nuetral..how could a charge be coming in on these
    >> conductors and getting past the MOVs to build a potential on the
    >> boards.
    >>
    >> Any ideas would be appreciated.
    >> TJS

    >
    > Put a humidifier inside the room, the air is too dry and static
    > electricity builds up.
    > --
    > ciao Ban
    > Apricale, Italy
    >
     
    T, Apr 4, 2006
    #4
  5. "T" <> schreef in bericht
    news:...
    >A raised floor server room with 6 servers, fiber optic patch panels, large
    >control system cabinets and large UPS system, has been recently been
    >plagued by computer power supply failures. The supplies fail when
    >apparently many tens of thousands of volts jump from inside the PS around
    >the switching regulators to the chassis of the supply taking out all the
    >components. This has happened to 8 supplies so far. A visible blue flash
    >has been witnessed several times by pewrsons in the room.
    >
    > The servers so far affected are all sitting on the raised computer center
    > floor. What ususally happens seems to be when a person enters the 12x20ft
    > room or gets near a server a large snap is heard and the server is on the
    > backup redundant PS, if it has not already failed.
    >
    > We have been adding grounding bonding from all computer case to the bldg
    > steel, raised floor structure, etc to try to stop this. Its still
    > happening. The computers are various brands and varoious ages, from 1 week
    > old to 5 years old. The probelm began occuring 2 months ago. The data
    > center was built 12 years ago.
    >
    > We are at a loss to figure out how the charge is building up on the inside
    > of the power supplies. I am thinking about the common power source, via
    > the power cords Hot, Neutral and Ground conductor.
    >
    > The green wire should be bonded to the PC case. Apparently the PS
    > regulator board floats above chassis potential. Apparently a large
    > potential differnce is building. It jumps a 1 inch gap to the chassis.
    > Burn marks from repeated arc overs are evindent (the arc that makes it
    > fail is not the 1st time it occurs!)
    >
    > The Hot and Nuetral..how could a charge be coming in on these conductors
    > and getting past the MOVs to build a potential on the boards.
    >
    >
    > Any ideas would be appreciated.
    > TJS
    >
    >
    >



    Is ground still connected to good old earth? You'll have to check to be
    sure. Suppose the metal of the floor and installation has been grounded
    carefully but you'll have to check this too. An open ground connection may
    be the cause of you problems. Especially an open connection that is closed
    again by someone entering the room.

    On all PCs and servers I know, the secondary of the power supply has been
    connected to the enclosure which in turn is grounded. So I assume the spark
    jumps from the primary of the power supply the the chassis. Looks like
    neutral and hot are floating which means that the neutral has not been
    connected to ground, at least not properly. (Don't know where neutral should
    be grounded in your place.)

    There are other possibillities. Did someone install a badly insulated neon
    sign near you? Some other renovation maybe? Something else I can't even
    imagine but not very likely. I'm pretty sure something is not grounded
    properly anymore, but what?

    petrus bitbyter
     
    petrus bitbyter, Apr 4, 2006
    #5
  6. T

    Guest

    T wrote:
    [...]
    >
    > The servers so far affected are all sitting on the raised computer center
    > floor. What ususally happens seems to be when a person enters the 12x20ft
    > room or gets near a server a large snap is heard and the server is on the
    > backup redundant PS, if it has not already failed.
    >

    [...]
    > Any ideas would be appreciated.
    > TJS


    A near identical situation was cured simply by spraying the carpet
    tiles in the computer room and access corridor, with anti static
    solution.
    john
     
    , Apr 5, 2006
    #6
  7. T

    T Guest

    We have ordered some conductive matting for walking on. Waiting for it while
    supplies are failing!

    <> wrote in message
    news:...
    >T wrote:
    > [...]
    >>
    >> The servers so far affected are all sitting on the raised computer center
    >> floor. What ususally happens seems to be when a person enters the 12x20ft
    >> room or gets near a server a large snap is heard and the server is on the
    >> backup redundant PS, if it has not already failed.
    >>

    > [...]
    >> Any ideas would be appreciated.
    >> TJS

    >
    > A near identical situation was cured simply by spraying the carpet
    > tiles in the computer room and access corridor, with anti static
    > solution.
    > john
    >
     
    T, Apr 5, 2006
    #7
  8. T

    T Guest

    My technicians have been testing the grounds to the steel and they are
    intact. We have a new fiber pull coming into the room just today via and
    existing conduit. The failures have been occuring for almost 2 months but
    much more frequently these last 2 weeks.



    "petrus bitbyter" <> wrote in message
    news:4432ea11$0$5636$4all.nl...
    >>

    >
    >
    > Is ground still connected to good old earth? You'll have to check to be
    > sure. Suppose the metal of the floor and installation has been grounded
    > carefully but you'll have to check this too. An open ground connection may
    > be the cause of you problems. Especially an open connection that is closed
    > again by someone entering the room.
    >
    > On all PCs and servers I know, the secondary of the power supply has been
    > connected to the enclosure which in turn is grounded. So I assume the
    > spark
    > jumps from the primary of the power supply the the chassis. Looks like
    > neutral and hot are floating which means that the neutral has not been
    > connected to ground, at least not properly. (Don't know where neutral
    > should
    > be grounded in your place.)
    >
    > There are other possibillities. Did someone install a badly insulated neon
    > sign near you? Some other renovation maybe? Something else I can't even
    > imagine but not very likely. I'm pretty sure something is not grounded
    > properly anymore, but what?
    >
    > petrus bitbyter
    >
    >
    >
     
    T, Apr 5, 2006
    #8
  9. T wrote:
    >
    > My technicians have been testing the grounds to the steel and they are
    > intact. We have a new fiber pull coming into the room just today via and
    > existing conduit. The failures have been occuring for almost 2 months but
    > much more frequently these last 2 weeks.


    I would have the electrical system inspected. The power transformer
    for the building may not be properly grounded. The ground rod or wiring
    may be damaged, leaving the transformer floating above ground.


    --
    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
     
    Michael A. Terrell, Apr 5, 2006
    #9
  10. T

    TJS Guest

    An update; We are investigating "zinc whiskers" phenomina as a possible
    cause. The zinc filaments are produced from the plywood core floor panels
    supported by the zinc electrocoted support structure. When floor panels are
    lifted or disturbed the conductive dust can get into the power supply and
    lead to shorts between the modern closely spaced SMT devices.
    See here for a white paper http://www.dataclean.com/pdf/zincwhiskers3.pdf

    The failures/arcs in our supplies have all arced from the 120vac chopper
    regulator collector to the PS case. If the zinc whisker problem is our case
    then the blue flash is just a 120/170p-p vac arc to ground, and not a static
    discharge.

    We are looking at replacing our floor tiles with the modern ultra low static
    floor tiles.

    I'm a little skeptical that this is the problem, but it is true that 2
    months ago we pulled floor tiles to look for fiber conduits and that about
    the time the problems began

    TJS


    "T" <> wrote in message
    news:...
    > A raised floor server room with 6 servers, fiber optic patch panels, large
    > control system cabinets and large UPS system, has been recently been

    plagued
    > by computer power supply failures. The supplies fail when apparently many
    > tens of thousands of volts jump from inside the PS around the switching
    > regulators to the chassis of the supply taking out all the components.

    This
    > has happened to 8 supplies so far. A visible blue flash has been witnessed
    > several times by pewrsons in the room.
    >
    > The servers so far affected are all sitting on the raised computer center
    > floor. What ususally happens seems to be when a person enters the 12x20ft
    > room or gets near a server a large snap is heard and the server is on the
    > backup redundant PS, if it has not already failed.
    >
    > We have been adding grounding bonding from all computer case to the bldg
    > steel, raised floor structure, etc to try to stop this. Its still

    happening.
    > The computers are various brands and varoious ages, from 1 week old to 5
    > years old. The probelm began occuring 2 months ago. The data center was
    > built 12 years ago.
    >
    > We are at a loss to figure out how the charge is building up on the inside
    > of the power supplies. I am thinking about the common power source, via

    the
    > power cords Hot, Neutral and Ground conductor.
    >
    > The green wire should be bonded to the PC case. Apparently the PS

    regulator
    > board floats above chassis potential. Apparently a large potential

    differnce
    > is building. It jumps a 1 inch gap to the chassis. Burn marks from

    repeated
    > arc overs are evindent (the arc that makes it fail is not the 1st time it
    > occurs!)
    >
    > The Hot and Nuetral..how could a charge be coming in on these conductors

    and
    > getting past the MOVs to build a potential on the boards.
    >
    >
    > Any ideas would be appreciated.
    > TJS
    >
    >
    >
    >
    >
     
    TJS, Apr 5, 2006
    #10
  11. Is the air conditioning overhead supply or raised floor supply?

    TJS wrote:
    > An update; We are investigating "zinc whiskers" phenomina as a possible
    > cause. The zinc filaments are produced from the plywood core floor panels
    > supported by the zinc electrocoted support structure. When floor panels are
    > lifted or disturbed the conductive dust can get into the power supply and
    > lead to shorts between the modern closely spaced SMT devices.
    > See here for a white paper http://www.dataclean.com/pdf/zincwhiskers3.pdf
    >
    > The failures/arcs in our supplies have all arced from the 120vac chopper
    > regulator collector to the PS case. If the zinc whisker problem is our case
    > then the blue flash is just a 120/170p-p vac arc to ground, and not a static
    > discharge.
    >
    > We are looking at replacing our floor tiles with the modern ultra low static
    > floor tiles.
    >
    > I'm a little skeptical that this is the problem, but it is true that 2
    > months ago we pulled floor tiles to look for fiber conduits and that about
    > the time the problems began
    >
    > TJS
    >
    >
    > "T" <> wrote in message
    > news:...
    >> A raised floor server room with 6 servers, fiber optic patch panels, large
    >> control system cabinets and large UPS system, has been recently been

    > plagued
    >> by computer power supply failures. The supplies fail when apparently many
    >> tens of thousands of volts jump from inside the PS around the switching
    >> regulators to the chassis of the supply taking out all the components.

    > This
    >> has happened to 8 supplies so far. A visible blue flash has been witnessed
    >> several times by pewrsons in the room.
    >>
    >> The servers so far affected are all sitting on the raised computer center
    >> floor. What ususally happens seems to be when a person enters the 12x20ft
    >> room or gets near a server a large snap is heard and the server is on the
    >> backup redundant PS, if it has not already failed.
    >>
    >> We have been adding grounding bonding from all computer case to the bldg
    >> steel, raised floor structure, etc to try to stop this. Its still

    > happening.
    >> The computers are various brands and varoious ages, from 1 week old to 5
    >> years old. The probelm began occuring 2 months ago. The data center was
    >> built 12 years ago.
    >>
    >> We are at a loss to figure out how the charge is building up on the inside
    >> of the power supplies. I am thinking about the common power source, via

    > the
    >> power cords Hot, Neutral and Ground conductor.
    >>
    >> The green wire should be bonded to the PC case. Apparently the PS

    > regulator
    >> board floats above chassis potential. Apparently a large potential

    > differnce
    >> is building. It jumps a 1 inch gap to the chassis. Burn marks from

    > repeated
    >> arc overs are evindent (the arc that makes it fail is not the 1st time it
    >> occurs!)
    >>
    >> The Hot and Nuetral..how could a charge be coming in on these conductors

    > and
    >> getting past the MOVs to build a potential on the boards.
    >>
    >>
    >> Any ideas would be appreciated.
    >> TJS
    >>
    >>
    >>
    >>
    >>

    >
    >
     
    Bennett Price, Apr 5, 2006
    #11
  12. T

    Franc Zabkar Guest

    On Wed, 05 Apr 2006 12:59:59 GMT, "TJS" <> put finger to
    keyboard and composed:

    >An update; We are investigating "zinc whiskers" phenomina as a possible
    >cause. The zinc filaments are produced from the plywood core floor panels
    >supported by the zinc electrocoted support structure. When floor panels are
    >lifted or disturbed the conductive dust can get into the power supply and
    >lead to shorts between the modern closely spaced SMT devices.
    >See here for a white paper http://www.dataclean.com/pdf/zincwhiskers3.pdf
    >
    >The failures/arcs in our supplies have all arced from the 120vac chopper
    >regulator collector to the PS case. If the zinc whisker problem is our case
    >then the blue flash is just a 120/170p-p vac arc to ground, and not a static
    >discharge.
    >
    >We are looking at replacing our floor tiles with the modern ultra low static
    >floor tiles.
    >
    >I'm a little skeptical that this is the problem, but it is true that 2
    >months ago we pulled floor tiles to look for fiber conduits and that about
    >the time the problems began
    >
    >TJS


    What are the chances of zinc whiskers causing *exactly* the same fault
    in *8* PSUs?

    - Franc Zabkar
    --
    Please remove one 'i' from my address when replying by email.
     
    Franc Zabkar, Apr 5, 2006
    #12
  13. T

    T Guest

    I'm skeptical about zinc whiskers and the white paper does come from a
    cleaning service company, enough said. But still it is a consideration


    "Franc Zabkar" <> wrote in message
    news:...
    > On Wed, 05 Apr 2006 12:59:59 GMT, "TJS" <> put finger to
    > keyboard and composed:
    >
    >>An update; We are investigating "zinc whiskers" phenomina as a possible
    >>cause. The zinc filaments are produced from the plywood core floor panels
    >>supported by the zinc electrocoted support structure. When floor panels
    >>are
    >>lifted or disturbed the conductive dust can get into the power supply and
    >>lead to shorts between the modern closely spaced SMT devices.
    >>See here for a white paper http://www.dataclean.com/pdf/zincwhiskers3.pdf
    >>
    >>The failures/arcs in our supplies have all arced from the 120vac chopper
    >>regulator collector to the PS case. If the zinc whisker problem is our
    >>case
    >>then the blue flash is just a 120/170p-p vac arc to ground, and not a
    >>static
    >>discharge.
    >>
    >>We are looking at replacing our floor tiles with the modern ultra low
    >>static
    >>floor tiles.
    >>
    >>I'm a little skeptical that this is the problem, but it is true that 2
    >>months ago we pulled floor tiles to look for fiber conduits and that about
    >>the time the problems began
    >>
    >>TJS

    >
    > What are the chances of zinc whiskers causing *exactly* the same fault
    > in *8* PSUs?
    >
    > - Franc Zabkar
    > --
    > Please remove one 'i' from my address when replying by email.
     
    T, Apr 6, 2006
    #13
  14. T

    T Guest

    AC is from overhead

    "Bennett Price" <> wrote in message
    news:XcTYf.8591$...
    > Is the air conditioning overhead supply or raised floor supply?
    >
    > TJS wrote:
    >> An update; We are investigating "zinc whiskers" phenomina as a possible
    >> cause. The zinc filaments are produced from the plywood core floor panels
    >> supported by the zinc electrocoted support structure. When floor panels
    >> are
    >> lifted or disturbed the conductive dust can get into the power supply and
    >> lead to shorts between the modern closely spaced SMT devices.
    >> See here for a white paper
    >> http://www.dataclean.com/pdf/zincwhiskers3.pdf
    >>
    >> The failures/arcs in our supplies have all arced from the 120vac chopper
    >> regulator collector to the PS case. If the zinc whisker problem is our
    >> case
    >> then the blue flash is just a 120/170p-p vac arc to ground, and not a
    >> static
    >> discharge.
    >>
    >> We are looking at replacing our floor tiles with the modern ultra low
    >> static
    >> floor tiles.
    >>
    >> I'm a little skeptical that this is the problem, but it is true that 2
    >> months ago we pulled floor tiles to look for fiber conduits and that
    >> about
    >> the time the problems began
    >>
    >> TJS
    >>
    >>
    >> "T" <> wrote in message
    >> news:...
    >>> A raised floor server room with 6 servers, fiber optic patch panels,
    >>> large
    >>> control system cabinets and large UPS system, has been recently been

    >> plagued
    >>> by computer power supply failures. The supplies fail when apparently
    >>> many
    >>> tens of thousands of volts jump from inside the PS around the switching
    >>> regulators to the chassis of the supply taking out all the components.

    >> This
    >>> has happened to 8 supplies so far. A visible blue flash has been
    >>> witnessed
    >>> several times by pewrsons in the room.
    >>>
    >>> The servers so far affected are all sitting on the raised computer
    >>> center
    >>> floor. What ususally happens seems to be when a person enters the
    >>> 12x20ft
    >>> room or gets near a server a large snap is heard and the server is on
    >>> the
    >>> backup redundant PS, if it has not already failed.
    >>>
    >>> We have been adding grounding bonding from all computer case to the bldg
    >>> steel, raised floor structure, etc to try to stop this. Its still

    >> happening.
    >>> The computers are various brands and varoious ages, from 1 week old to 5
    >>> years old. The probelm began occuring 2 months ago. The data center was
    >>> built 12 years ago.
    >>>
    >>> We are at a loss to figure out how the charge is building up on the
    >>> inside
    >>> of the power supplies. I am thinking about the common power source, via

    >> the
    >>> power cords Hot, Neutral and Ground conductor.
    >>>
    >>> The green wire should be bonded to the PC case. Apparently the PS

    >> regulator
    >>> board floats above chassis potential. Apparently a large potential

    >> differnce
    >>> is building. It jumps a 1 inch gap to the chassis. Burn marks from

    >> repeated
    >>> arc overs are evindent (the arc that makes it fail is not the 1st time
    >>> it
    >>> occurs!)
    >>>
    >>> The Hot and Nuetral..how could a charge be coming in on these conductors

    >> and
    >>> getting past the MOVs to build a potential on the boards.
    >>>
    >>>
    >>> Any ideas would be appreciated.
    >>> TJS
    >>>
    >>>
    >>>
    >>>
    >>>

    >>
     
    T, Apr 6, 2006
    #14
  15. T

    Franc Zabkar Guest

    On Wed, 5 Apr 2006 22:05:11 -0400, "T" <> put finger to
    keyboard and composed:

    >I'm skeptical about zinc whiskers and the white paper does come from a
    >cleaning service company, enough said. But still it is a consideration


    I wonder why the arc jumps a 1" gap between the chopper and the
    chassis. Why not the much smaller (?) gap on the underside of the PCB?

    - Franc Zabkar
    --
    Please remove one 'i' from my address when replying by email.
     
    Franc Zabkar, Apr 6, 2006
    #15
  16. T

    GregS Guest

    In article <>, wrote:
    >On Wed, 05 Apr 2006 12:59:59 GMT, "TJS" <> put finger to
    >keyboard and composed:
    >
    >>An update; We are investigating "zinc whiskers" phenomina as a possible
    >>cause. The zinc filaments are produced from the plywood core floor panels
    >>supported by the zinc electrocoted support structure. When floor panels are
    >>lifted or disturbed the conductive dust can get into the power supply and
    >>lead to shorts between the modern closely spaced SMT devices.
    >>See here for a white paper http://www.dataclean.com/pdf/zincwhiskers3.pdf
    >>
    >>The failures/arcs in our supplies have all arced from the 120vac chopper
    >>regulator collector to the PS case. If the zinc whisker problem is our case
    >>then the blue flash is just a 120/170p-p vac arc to ground, and not a static
    >>discharge.
    >>
    >>We are looking at replacing our floor tiles with the modern ultra low static
    >>floor tiles.
    >>
    >>I'm a little skeptical that this is the problem, but it is true that 2
    >>months ago we pulled floor tiles to look for fiber conduits and that about
    >>the time the problems began
    >>
    >>TJS

    >
    >What are the chances of zinc whiskers causing *exactly* the same fault
    >in *8* PSUs?


    Identical or different?
     
    GregS, Apr 6, 2006
    #16
  17. T

    James Sweet Guest

    T wrote:
    > A raised floor server room with 6 servers, fiber optic patch panels, large
    > control system cabinets and large UPS system, has been recently been plagued
    > by computer power supply failures. The supplies fail when apparently many
    > tens of thousands of volts jump from inside the PS around the switching
    > regulators to the chassis of the supply taking out all the components. This
    > has happened to 8 supplies so far. A visible blue flash has been witnessed
    > several times by pewrsons in the room.
    >
    > The servers so far affected are all sitting on the raised computer center
    > floor. What ususally happens seems to be when a person enters the 12x20ft
    > room or gets near a server a large snap is heard and the server is on the
    > backup redundant PS, if it has not already failed.
    >
    > We have been adding grounding bonding from all computer case to the bldg
    > steel, raised floor structure, etc to try to stop this. Its still happening.
    > The computers are various brands and varoious ages, from 1 week old to 5
    > years old. The probelm began occuring 2 months ago. The data center was
    > built 12 years ago.
    >
    > We are at a loss to figure out how the charge is building up on the inside
    > of the power supplies. I am thinking about the common power source, via the
    > power cords Hot, Neutral and Ground conductor.
    >
    > The green wire should be bonded to the PC case. Apparently the PS regulator
    > board floats above chassis potential. Apparently a large potential differnce
    > is building. It jumps a 1 inch gap to the chassis. Burn marks from repeated
    > arc overs are evindent (the arc that makes it fail is not the 1st time it
    > occurs!)
    >
    > The Hot and Nuetral..how could a charge be coming in on these conductors and
    > getting past the MOVs to build a potential on the boards.
    >
    >
    > Any ideas would be appreciated.
    > TJS
    >
    >
    >
    >
    >



    I think static is highly unlikely as the cause here. My guess would be
    overvoltage on the line, transients, or inadequate cooling.
     
    James Sweet, Apr 7, 2006
    #17
  18. On Tue, 04 Apr 2006 16:41:57 -0400, T wrote:
    ....
    > potential differnce is building. It jumps a 1 inch gap to the chassis.
    > Burn marks from repeated arc overs are evindent (the arc that makes it
    > fail is not the 1st time it occurs!)
    >
    > Any ideas would be appreciated.


    Call an exorcist. ;-)
    --
    Cheers!
    Rich
    ------
    "If you find for your verse there's no call,
    And you can't afford paper at all,
    For the true poet born,
    However forlorn,
    There is always the lavat'ry wall."
     
    Rich The Newsgroup Wacko, Apr 7, 2006
    #18
  19. T

    Rich Grise Guest

    On Wed, 05 Apr 2006 12:59:59 +0000, TJS wrote:

    > I'm a little skeptical that this is the problem, but it is true that 2
    > months ago we pulled floor tiles to look for fiber conduits and that about
    > the time the problems began


    Well, skeptical is good, but usually when troubleshooting, the first
    question is, "What changed?"

    This is a no-brainer. Start looking through your contract with the floor
    installer, to see if you can have him eat the cost of replacing the killer
    tile.

    Good Luck!
    Rich
     
    Rich Grise, Apr 7, 2006
    #19
  20. T

    Rich Grise Guest

    On Thu, 06 Apr 2006 08:05:33 +1000, Franc Zabkar wrote:

    > On Wed, 05 Apr 2006 12:59:59 GMT, "TJS" <> put finger to
    > keyboard and composed:
    >
    >>An update; We are investigating "zinc whiskers" phenomina as a possible
    >>cause. The zinc filaments are produced from the plywood core floor panels
    >>supported by the zinc electrocoted support structure. When floor panels are
    >>lifted or disturbed the conductive dust can get into the power supply and
    >>lead to shorts between the modern closely spaced SMT devices.
    >>See here for a white paper http://www.dataclean.com/pdf/zincwhiskers3.pdf
    >>
    >>The failures/arcs in our supplies have all arced from the 120vac chopper
    >>regulator collector to the PS case. If the zinc whisker problem is our case
    >>then the blue flash is just a 120/170p-p vac arc to ground, and not a static
    >>discharge.
    >>
    >>We are looking at replacing our floor tiles with the modern ultra low static
    >>floor tiles.
    >>
    >>I'm a little skeptical that this is the problem, but it is true that 2
    >>months ago we pulled floor tiles to look for fiber conduits and that about
    >>the time the problems began
    >>
    >>TJS

    >
    > What are the chances of zinc whiskers causing *exactly* the same fault
    > in *8* PSUs?
    >


    Pretty good, considering that the tiles are the only thing that changed.

    I probably wouldn't say, "zinc whiskers", but I'm pretty sure that, except
    for galvanizing garbage cans, zinc is AWFUL! It gets all over everything.
    I once worked at a place where they had to scrap a $100,000.00 (or so)
    Ultra-High-Vacuum bell jar because someone had installed brass connectors -
    the zinc outgassed, and contaminated the whole thing.

    Maybe you could leach the zinc out of your tile by washing it down with
    muriatic acid. ;-) [1]

    I've also seen an installation where a bunch of boxes running off 277V
    lighting power started arcing, and the only conductive thing in the room
    was the dust from the desert setting, which could very well have been
    conductive - it was only about 100 miles from Great Salt Lake. We fixed
    it by putting furnace filters on top of all of the boxes, which the idiot
    designer had put all of the intake air vents on the top of. =:-O

    It was a pretty sweet TDY[2], though - $1000.00/week plus per diem plus
    expenses plus airplane ticket plus car rental. ;-)

    Good Luck!
    Rich
    [1] That's a joke, by the way. If you do use muriatic acid on zinc, be
    sure that you're in a very very well-ventilated place, because it makes
    hydrogen gas. But then, you could use the zinc chloride for sunscreen;
    just mix it with yogurt. ;-)
    [2] Temporary DutY
     
    Rich Grise, Apr 7, 2006
    #20
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. ltj

    blowing power supplies ;(

    ltj, Apr 20, 2004, in forum: Electronic Components
    Replies:
    4
    Views:
    268
  2. T
    Replies:
    21
    Views:
    724
    Franc Zabkar
    Apr 8, 2006
  3. T
    Replies:
    26
    Views:
    587
    Franc Zabkar
    Apr 8, 2006
  4. rory

    Detectors for Computer Server Rooms

    rory, Nov 6, 2004, in forum: Security Alarms
    Replies:
    3
    Views:
    263
  5. mm
    Replies:
    1
    Views:
    412
Loading...

Share This Page