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  1. #1
    Join Date
    Apr 2012
    Location
    chicago burbs
    Posts
    75

    What caused it to go bad?

    3 phase contactor went bad, white fluffy stuff by pitted end. What caused this and how? Seriously curious.

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  2. #2
    Join Date
    Apr 2012
    Location
    chicago burbs
    Posts
    75
    Name:  uploadfromtaptalk1371865929890.jpg
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  3. #3
    Join Date
    Dec 2008
    Location
    Ontario Canada
    Posts
    546
    Wire not tight?

  4. #4
    Join Date
    Apr 2012
    Location
    chicago burbs
    Posts
    75
    Possibly, had just spades on wires. But the corrosion on just one phase?? One terminal?

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  5. #5
    Join Date
    Aug 2002
    Location
    Southold.calm
    Posts
    5,688
    Bad connections started the problem. We see that a lot due to salt air.

  6. #6
    Join Date
    Apr 2012
    Location
    chicago burbs
    Posts
    75
    Heard that before, even southern coastal units vs midwest last 8/12 years beacuase of run time and salt. I think midwest is about 15/20ish? Been reading that low voltage can cause chattering as well. Just thought white stuff was a wierd corrosion, reaction to something only on 1 pole

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  7. #7
    Join Date
    Aug 2004
    Location
    Tucson, Az
    Posts
    337
    Looks like the corrosion found on automobile battery cables.

    I've not seen that type of corrosion on a contactor.

    Where is the equipment located?
    Jim
    Tucson, Az
    Keeping the Ice Cream Frozen!

  8. #8
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,667

  9. #9
    Join Date
    Jul 2011
    Location
    Lehigh Valley, PA
    Posts
    447
    Loose connections get warm/hot and eventually burn up. Sometimes I have seen them get corroded too. I think it has something to do with the aluminum connectors on the contactor.

  10. #10
    Join Date
    Jun 2013
    Location
    N. Canada
    Posts
    402
    Quote Originally Posted by leaker2 View Post
    3 phase contactor went bad, white fluffy stuff by pitted end. What caused this and how? Seriously curious.
    Chemical reaction (aka corrosion) is directly proportional to temperature.
    Note the contactor points... #3 badly burnt=most corrosion. #2 appears to have a start of corrosion (warmed), and removed #1 seems to have a touch.
    The airborne element that caused the reaction-that's another question.

    edit: not caused by loose wires.
    note the #3 points & bar overheating shows resistance BETWEEN fixed points. Remember your nursery rhymes? Twinkle twinkle little star,
    Power equals I squared R .

  11. #11
    Join Date
    Mar 2011
    Location
    Nw.Connecticut
    Posts
    301
    copper conductor aluminum terminal=========== loose.

  12. #12
    Join Date
    Apr 2012
    Location
    chicago burbs
    Posts
    75
    Equipment was on a rooftop with about 15 other 3_5 ton units and a couple packages. Just office buildings, but right next to I94 in chicago. Hate using spaded connectors as they are almost always loose on high volts.

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