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Typical current range for locked rotor current

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    Typical current range for locked rotor current

    The biggest enemy to insulating systems is heat. Current magnitude during most of the starting acceleration time is very close to locked-rotor current. What is the typical current range for locked rotor current of a large induction motor?

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    Quote Originally Posted by dharmikpandya0 View Post
    The biggest enemy to insulating systems is heat. Current magnitude during most of the starting acceleration time is very close to locked-rotor current. What is the typical current range for locked rotor current of a large induction motor?
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    Quote Originally Posted by test11 View Post
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    bellow is the tech quiz question. The link that follows the question leads me right to this thread.... I would say 4 to 6 times is the correct answer. What are your thoughts? I have not been able to find a reference that supports 6 to 8

    The biggest enemy to insulating systems is heat. Current magnitude during most of the starting acceleration time is very close to locked-rotor current. What is the typical current range for locked rotor current of a large induction motor?
    Your Answer: 4 to 6 times rated current
    Correct Answer: 6 to 8 times rated current

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    Quote Originally Posted by bec51392 View Post
    bellow is the tech quiz question. The link that follows the question leads me right to this thread.... I would say 4 to 6 times is the correct answer. What are your thoughts? I have not been able to find a reference that supports 6 to 8

    The biggest enemy to insulating systems is heat. Current magnitude during most of the starting acceleration time is very close to locked-rotor current. What is the typical current range for locked rotor current of a large induction motor?
    Your Answer: 4 to 6 times rated current
    Correct Answer: 6 to 8 times rated current
    This specific question comes from the Tech Quiz found in the 2014 Summer edition of NETAWorld:
    Question
    2. The biggest enemy to insulating systems is heat. Current magnitude during most of
    the starting acceleration time is very close to locked-rotor current. What is the typical
    current range for locked-rotor current of a large induction motor?
    a. 2 to 4 times rated current
    b. 4 to 6 times rated current
    c. 6 to 8 times rated current
    d. 8 to 10 times rated current
    e. 10 to 12 times rated current
    Answer:
    2. The best answer in this grouping is c. Many large induction motors will draw 6 to 8 times their full-load current during locked rotor conditions.


    This question is slightly vague as you will find different motor stats will create different starting/LRA currents, and documentation may say 4 to 6, 5 to 7, or 6 to 8 times normal current ratings. As for NETA questions, the Tech Quizzes provide the base for most questions found in this database and the test database. That being said the question pool is much larger than the number of questions found in the NETAworld tech quizzes.

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