FIGURE 9.1 below shows a gear-drive system - NSC Mechanical Technology Automotive - Question 9 - 2017 - Paper 1

To calculate the rotation frequency of the output shaft, we first need to determine the relationship between the gears:

1. Determine the input speed: The electric motor rotates at 1660 r/min, therefore:

   $N_{INPUT} = 1660 \text{ r/min}$

2. Use Gear Ratios: The gear ratio between gears A and B (A to B):

   $\frac{T_A}{T_B} = \frac{18}{36} = \frac{1}{2}$

3. Calculate the output speed from gear B to C:

   $N_{B} = N_{INPUT} \times \frac{T_A}{T_B} = 1660 \times \frac{1}{2} = 830 \text{ r/min}$

4. Calculate the gear ratio between gear C and D:

   $\frac{T_C}{T_D} = \frac{16}{46}$

5. Calculate the final output speed (N_OUTPUT):

   $N_{OUTPUT} = N_{B} \times \frac{T_C}{T_D} = 830 \times \frac{16}{46} \approx 288.70 \text{ r/min}$

This calculation shows that the rotation frequency of the output shaft is approximately 288.70 r/min.