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  1. #1
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    Sep 2014
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    Adjustable Motor starter ampherage setting

    Hi Guys,

    I have a motor with 600v 3 phase -- 5 hp -- and I am installing a new motor starter with a built in adjustable overload. The service factor for the motor is 1.25 . What do I set the overload to? FLA?

    I was told that motor starters with adjustable amp settings have the 25% higher than FLA amps built in and you adjust the dial to FLA only and not add another 25% above the FLA rating. Is this correct?

    Ive been told by some mechanics that I add 25% above the FLA when setting the dial

    but I was told by my instructor in school that you only set the dial to FLA as the adjustable overloads have the +25 percent needed built-in.

    Which is correct?

    Thanks!

  2. #2
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    Sep 2007
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    edmonds wa
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    Get the info from the Mfg of motor starter!
    UA Local 32

  3. #3
    Join Date
    Nov 2006
    Location
    Southeastern Pa
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    Quote Originally Posted by buford View Post
    Get the info from the Mfg of motor starter!
    Bingo. The manufacturer of the starter has approved overcurrent setting instructions.

    In the code, the general spec is that a motor with a service factor of 1.15 can have its overload device set for no more than 125% of FLA. (430.6 A 2)

    Bear in mind for general information....motors that have a service factor greater than 1.0 have that listing for being able to accept the heat of additional loading for transient periods of time. The service factor is not a rating that is indented for continuous load above FLA.
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    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

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  4. #4
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    Sep 2014
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    Thread Starter
    My understanding is -- I go to the electrical supplier -- tell them what my FLA is of my motor with my service factor get a motor starter with overload protection -- and then after I read the manual it will tell me if my FLA dial setting includes 25 % or if I have to add 25% to the FLA

  5. #5
    Join Date
    Sep 2007
    Location
    edmonds wa
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    Basically yes, the instructions in or with the overload protection will spell this out. Most have this info online.
    UA Local 32

  6. #6
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    Sep 2014
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    Thread Starter
    Thanks!

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