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? asked in 科學及數學其他 - 科學 · 10 years ago

Ac motor

An Ac motor with 4-polw piece with 400Hz power applied. The rotation speed is ?

a, 12000rpm

b.1200rpm

c.120rpm

1 Answer

Rating
  • 天同
    Lv 7
    10 years ago
    Favorite Answer

    Use the equation, rpm = 2f x 60/p

    where rpm is rotational speed of the motor

    f is the frequency of the ac supply

    p is the number of magnetic poles

    Hence, rpm =2 x 400 x 60/4 = 12 000

    The answer is option A

    Please refer to the following web-page for the above equation:

    http://international-electrical-supplies.com/motor...

    2011-07-07 16:13:44 補充:

    "rpm" denotes "revolution per minute".

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