Power of the motor and the minimum weight of the flywheel

Question

(a) A machine of mass 68 kg is mounted on springs of combined stiffness k = 1100 N/mm with an assumed damping factor of 0.2. A piston within the machine of mass 2 kg has reciprocating motion with a stroke of 75 mm and a speed of 3000 rpm. Assuming he motion of the piston to be simple harmonic, determine.

1. the amplitude of vibration of the machine
2. the phase angle with respect to the existing force and
3. the transmissibility and the force transmitted to the foundation.                                

(b) A punching press is drived by a constant torque electric motor. The press is provided with a flywheel that rotates at a maximum speed of 225 rpm. Radius of gyration of the flywheel is 0.5 m. The press punches 70 holes per hour, each punching operation takes 2 seconds and requires 15 KN-m of energy. Find the power of the motor and the minimum weight of the flywheel if the speed of the same is not to fall below 200 rpm.

 

 

Answer 1

(a) Given a simple spring mass machine

(b)