Function of Fly-Wheels in Connection with Electrically Operated Rolling Mills

H. C. Specht
1909 Transactions of the American Institute of Electrical Engineers  
mill service, where the load conditions are very unstable, the use of a suitable fly-wheel is of great importance. As is well known, the function of a fly-wheel is to take up the sudden shocks and equalize the unsteady loads as much as practicable in order to produce the cheapest installation and obtain the most satisfactory and economical operation. The smallest size of motor and the minimum capacity of the generating plant are obtained when the action of the fly-wheel is such that the load on
more » ... ch that the load on the motor is constant and equal to the average of all the loads. To a certain extent this will be impossible in rolling mills, and it will be the problem for the engineer to determine the most suitable size of fly-wheel, motor, and generating plant with the auxiliary equipments. In reviewing the characteristics of the load curve of a flywheel in connection with an induction motor, attention is called to Fig. 1 , in which the area A B C D represents a peak load, the ordinates giving the torque in pounds at 1 ft. radius on the shaft of the motor or the mill and the abscissas giving the time of rolling in seconds. Assume that a constant resistance is inserted in the secondary circuit of the motor and that the motor is carrying all the load until the peak is reached. We will then obtain the torque curve A E, the section below the line A E representing the torque developed by the motor and that above A E the torque delivered by the fly-wheel. During this time the speed of the motor has decreased somewhat, thus making it possible for the 8619
doi:10.1109/t-aiee.1909.4768212 fatcat:mnsbgkoa7fhlxj736iosh3naee