Answer:
8 poles
Explanation:
Given
[tex]Frequency, f = 60Hz[/tex]
[tex]Speed, n_s = 850rpm[/tex]
Required
Calculate the number of poles the motor should have?
To solve this question, we make use of synchronous angular velocity formula
[tex]n_s = \frac{120f}{P}[/tex]
Where
[tex]P = Number\ of\ Poles[/tex]
Substitute values for [tex]n_s[/tex] and f in [tex]n_s = \frac{120f}{P}[/tex]
[tex]850 = \frac{120 * 60}{P}[/tex]
[tex]850 = \frac{7200}{P}[/tex]
Multiply both sides by P
[tex]P * 850 = \frac{7200}{P} * P[/tex]
[tex]P * 850 = 7200[/tex]
Divide both sides by 850
[tex]\frac{P * 850}{850} = \frac{7200}{850}[/tex]
[tex]P = \frac{7200}{850}[/tex]
[tex]P = 8.47058823529[/tex]
However, the number of poles must be an integer.
So:
[tex]P = 8[/tex]
