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more amps less torque??

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#1 plt


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Posted 14 November 2004 - 03:53 AM

please understand that i am an apprentice electrician 2nd year and not exposed to motors that much but they facinate me. if my inexperience is too much let me know. i read the induction control theory at the home page and have a question. Less amps less torque at start up yet torque is proportional to amps??? this is confusing. What am I missing?? is that directly or inderectly proportional??

#2 marke


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Posted 14 November 2004 - 06:09 PM

Hello plt

If you reduce the start voltage to a motor, you will reduce the start current. (ohms law applies) If you reduce the start current, you will reduce the flux in the gap, (between rotor and stator) and therefore you will also reduce the starting torque.
The reduction in start torque is directly proportional to the reduction in voltage or current squared. i.e. half voltage will result in one quarter torque. One third current will result in one nineth torque.

Does this answer your question??

Best regards,

#3 plt


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Posted 16 November 2004 - 02:46 AM

yes that about does it. sounds simple now. thank you very much.

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