A 500 kg electric motor is mounted on flexible supports causing the supports to deflect downward by 6.37 mm. The supports exert a total damping force equal to 50% of the critical value, the damping being proportional to the velocity of motion. (a) Determine the natural frequency, spring stiffness and damping ratio of the system. (b) (c) When the motor is running at 750 rev/min., a sinusoidally varying out of balance vertical force of magnitude 3 kN is produced. Develop an expression that governs the vertical motion of the motor as a function of time. Calculate the maximum percentage force transmitted to the foundation. Suggest ways, giving appropriate reasons, in which this can be reduced. You may consult if you wish to, the figures 8 below showing variation of amplitude ratio (AR) and transmission ratio (TR) with frequency ratio,

A 500 kg electric motor is mounted on flexible supports causing the supports to deflect downward by 6.37 mm. The supports exert a total damping force equal to 50% of the critical value, the damping being proportional to the velocity of motion. (a) Determine the natural frequency, spring stiffness and damping ratio of the system. (b) (c) When the motor is running at 750 rev/min., a sinusoidally varying out of balance vertical force of magnitude 3 kN is produced. Develop an expression that governs the vertical motion of the motor as a function of time. Calculate the maximum percentage force transmitted to the foundation. Suggest ways, giving appropriate reasons, in which this can be reduced. You may consult if you wish to, the figures 8 below showing variation of amplitude ratio (AR) and transmission ratio (TR) with frequency ratio,

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

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