Question 6.P.3: An electric motor weighing 1160 N is attached to a floor bea...

Dynamics of Structures

An electric motor weighing $1160 N$ is attached to a floor beam which deflects $0.76 mm$ under the weight. The armature of the motor weighs $40 kg$ . As the motor is run up gradually to operating speed of 1600 RPM, it is observed that the maximum amplitude of oscillation is $2.5 mm$ , decreasing to $0.5 mm$ at the operating speed. Calculate the damping coefficient and the eccentricity of the armature from its axis of rotation.

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