Electric Motor Physics Example 3

Solution

1. 1
   Input power: $P_{\text{in}} = VI = 240 \times 2.5 = 600 \text{ W}$.
2. 2
   Angular speed: $\omega = \frac{2\pi \times 2400}{60} = 251.3 \text{ rad/s}$. Mechanical output: $P_{\text{out}} = \tau\omega = 1.2 \times 251.3 = 301.6 \text{ W}$.
3. 3
   Efficiency: $$\eta = \frac{P_{\text{out}}}{P_{\text{in}}} \times 100\% = \frac{301.6}{600} \times 100\% \approx 50.3\%$$