Jump to latest postThe 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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Junior Member
Posted April 12, 2020
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?
Originally Posted by dharmikpandya0
NETA Level III
Posted January 5, 2021
Pro Subscriber
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
Experienced Member
Posted January 5, 2021
Pro Subscriber
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.
