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Thread: MI PSI Practice Exam Question

  1. #11
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    Quote Originally Posted by Padilla616 View Post
    Q: What is the motor nameplate FLA rating ...
    There is no way to mathematically answer this question.
    The correct answer can only be found by physically looking at the motor's Nameplate FLA.


    The code FLA current is found by looking in the NEC.
    The theoretical FLA have already been discussed in post #2.
    Just because you can, doesn't mean you should.

  2. #12
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    I would guess that they asked for nameplate so you wouldn't use a table in the NEC and perform the calculation in post #2.
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

  3. #13
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    Quote Originally Posted by infinity View Post
    I would guess that they asked for nameplate so you wouldn't use a table in the NEC and perform the calculation in post #2.
    Mediocre questions get mediocre answers.

    The NEC does talk specifically about using the FLA on the nameplate when sizing running overload protection. Nameplate information is not found anywhere but on the motor.
    It appears the question is looking for the calculated running amps of the specified motor.
    Just because you can, doesn't mean you should.

  4. #14
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    Quote Originally Posted by jim dungar View Post
    Mediocre questions get mediocre answers.
    I agree poor question but I think that many here could find the answer they were looking for using Besoeker's method.
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

  5. #15
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    Cloverdale,Va.
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    correction

    sorry, (h.p.x746)

  6. #16
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    conductor size and short circuit and ground fault protection is based on FLC, overload is based on nameplate FLA.
    The formula for FLA is (h.p.x746)/(ExEFFxPF). They just want you to know that the FLA is based upon motor ratings and do not truly indicate actual load of motor.
    430.6(a)(1)
    430.(52)(c)(1)

    overload-430.6(a)(2) based on nameplate. FLC=Code, FLA= Actual nameplate.

  7. #17
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    Quote Originally Posted by infinity View Post
    I agree poor question but I think that many here could find the answer they were looking for using Besoeker's method.

    I agree.. Bes nailed it. and we are trying to make it more complicated than it is. Test question are generally not perfect.

    Texie the test question was looking for a nameplate amps not the NEC code requirement.
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky



  8. #18
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    Quote Originally Posted by K8MHZ View Post
    I just Googled a couple 5hp motors and checked the nameplates. One had an FLA of 22, the other 25 at 230 volts.

    Besoeker's math makes total sense to me. I don't understand where the NEC came up with 28 amps.
    Thank you kindly.
    Just arithmetic.
    Si hoc legere scis nimium eruditionis habes.

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