A press has to punch 30 holes per minute and the motor delivers 1.5 kW to the press uniformly. If the actual punching of each hole is accomplished during 300 of crank rotation of the punching machine and the fluctuation of speed is not to exceed ±10%, determine the minimum moment of inertial of the flywheel which is directly mounted on the crankshaft. Neglect the intertia of the rest of the system.