Calculating Frequency for Induction Motors with Given Horsepower and Pole Count

AI Thread Summary
To calculate the frequency for an induction motor with 10 horsepower and four poles, the synchronous speed (ns) can be determined using the formula ns = 120 * frequency / number of poles. The rated speed of the motor is typically within 5% of the synchronous speed. The formula for induced torque is given as Pgap / Ws, where Ws requires the frequency for calculation. In engineering, answers that are within 10% of the expected value are generally considered acceptable. Understanding these principles is crucial for accurate motor performance analysis.
onceinalifetim
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Hello

I'm doing a question in induction motor now.

formula for Induced torque is Pgap / Ws.

i have found the Pgap, but in order to find Ws, i need frequency to find ns..
so my question is, how to find frequency with only given 10hp and four pole
 
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The rated speed of an induction motor is typically within 5% of that motor's synchronous speed. http://www.engineeringtoolbox.com/speed-electrical-motors-d_738.html

Broadly speaking, in engineering, an answer correct to within 10% is generally acceptable. There are always exceptions to rules of thumb, but I can't see the question under discusion being one of them. :smile:
 
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