Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
An Ac motor with 4-polw piece with 400Hz power applied. The rotation speed is ?
- 天同Lv 710 years agoFavorite 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:
2011-07-07 16:13:44 補充：
"rpm" denotes "revolution per minute".