Question

The torque (N-m) required to drive a machine is as shown in figure. It takes 2 seconds to complete 1 cycle whereas the motor supplying the power is running at a speed of 300 rpm. The size of the flywheel to be attached on the motor shaft to limit the fluctuations of speed with 1% on either side of the mean speed is

• A. $103.45kg-m^2$
• B. $414kg-m^2$
• C. $42kg-m^2$
• D. $207kg-m^2$

Answer 1

The correct option is A $103.45kg-m^2$

Area of graph gives energy required in a cycle

$E=200\pi +1000\pi +100\times 2\pi$

$E=1400\pi$

$T_m\times 4\pi =1400\pi$

$T_m=350Nm$

$\Delta E=(T_{max}-T_{mean})\pi =650\pi$

$\omega =10\pi$

$\Delta E=I{\omega }_{mean}^2{C}_s$

$650\pi =I\times (10\pi {)}^2\times 0.02$

$I=103.35kg-m^2$