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Thread: exploding surge protector

  1. #31
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    Quote Originally Posted by Sahib View Post
    It is an ungrounded system both upstream and downstream to a transformer, the ground fault current would not be high and there is no chance of fault current turning from 'A' to 'kA' to rupture/explode the arrester and so the arrester should stay grounded under such fault conditions.
    I2t

  2. #32
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    Sorry, I remain unconvinced because of the possibility of thermal equilibrium preventing rupture of the arrester due to low I2t.

  3. #33
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    Quote Originally Posted by Sahib View Post
    It is an ungrounded system both upstream and downstream to a transformer, the ground fault current would not be high........
    If the system is ungrounded on both upstream and downstream sides of the transformer, the voltage to ground is indeterminate. The whole system is floating. Even with a primary to secondary fault, it would still be floating. Indeterminate WRT ground.
    In such a case, it is nonsensical to suggest, as you did in post #21, that "protection against over voltage in this case is afforded by MOV's discs connected between each phase and ground"
    Mods, don't worry. I'm not going argue the point. It's just too silly to bother with.

  4. #34
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    Quote Originally Posted by Besoeker View Post
    If the system is ungrounded on both upstream and downstream sides of the transformer, the voltage to ground is indeterminate. The whole system is floating. Even with a primary to secondary fault, it would still be floating. Indeterminate WRT ground.
    In such a case, it is nonsensical to suggest, as you did in post #21, that "protection against over voltage in this case is afforded by MOV's discs connected between each phase and ground"
    Mods, don't worry. I'm not going argue the point. It's just too silly to bother with.
    Even ungrounded system has nominal voltage to ground value defined for it. Capacitive effect may increase (not decrease) its actual value, thus making it indeterminate. But this is not relevant to the discussion here.

    Anyway please do not approach and touch any bare ungrounded system wire on the assumption that its voltage is indeterminate!

  5. #35
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    Quote Originally Posted by Besoeker View Post
    Even with a primary to secondary fault, it would still be floating. Indeterminate WRT ground.
    Yes, indeterminate WRT ground till the subject MOV breaks down and conducts through its ground lead. Then the ungrounded system faulted line HV becomes determinate and equals practically zero with respect to ground.

  6. #36
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    Quote Originally Posted by Sahib View Post
    Yes, indeterminate WRT ground till the subject MOV breaks down and conducts through its ground lead. Then the ungrounded system faulted line HV becomes determinate and equals practically zero with respect to ground.
    If you wish to discuss this nonsense further, please do so by PM.

  7. #37
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    Quote Originally Posted by Besoeker View Post
    If you wish to discuss this nonsense further, please do so by PM.
    See my PM. You did not understand at all.

  8. #38
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    Quote Originally Posted by Sahib View Post
    See my PM. You did not understand at all.
    I received no PM from you.

  9. #39
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    Quote Originally Posted by Besoeker View Post
    I received no PM from you.
    You should have had. Check your inbox again.

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