An electric motor, of mass \(20 \mathrm{~kg}\) and operating speed \(1350 \mathrm{rpm}\), is placed on a fixed-fixed steel beam of width \(15 \mathrm{~cm}\) and depth \(1.2 \mathrm{~cm}\), as shown in Fig. 9.53. The motor has a rotating

unbalance of \(0.1 \mathrm{~kg}-\mathrm{m}\). The amplitude of vibration of the beam under steady-state operation of the motor is suppressed by attaching an undamped vibration absorber underneath the motor, as shown in Fig. 9.53. Determine the mass and stiffness of the absorber such that the amplitude of the absorber mass is less than \(2 \mathrm{~cm}\).

Transcribed Image Text:

+ -0.5 m- 1 m- FIGURE 9.53 Absorber for motor with unbalance.