Question 13.19: Induction Motor Speed A six-pole, three-phase induction moto...

Using Equation (13.39), the synchronous speed of motor N_s is:

N=\frac{120 \cdot f}{P}     (13.39)

N_{s}=\frac{120 \times \text { frequency }}{\text { No. of poles }}=\frac{60  s/min \times 60  r/ s}{6 / 2}=1200 rpm

Using Equation (13.41):

s=\frac{N_{s}-N}{N_{s}}     (13.41)

N=N_{s}(1-s)=0.98 \times 1200=1176 r/min

In radians per second (see Equation (13.6)):

\omega=\frac{2 \pi N}{60}=\frac{\omega_m}{60}     (13.6)

ω = 123.15 rad/s.

Full-load speed is 1176 rpm.