Chapter 46, Problem 1RQ

To determine

The synchronous speed of the six pole motor operated with an applied voltage of 20 hertz.

Explanation of Solution

Consider the formula for the synchronous speed is,

    $N_s=\frac{120f}{P}$

Then, the synchronous speed is calculated as,

    $\begin{array}{c}{N}_s=\frac{120\left(20\right)}{6}\\ =400\text{rpm}\end{array}$

Thus, the synchronous speed is $400\text{rpm}$.